WO2019224134A1 - Semiconducting nanoparticle - Google Patents

Semiconducting nanoparticle Download PDF

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Publication number
WO2019224134A1
WO2019224134A1 PCT/EP2019/062910 EP2019062910W WO2019224134A1 WO 2019224134 A1 WO2019224134 A1 WO 2019224134A1 EP 2019062910 W EP2019062910 W EP 2019062910W WO 2019224134 A1 WO2019224134 A1 WO 2019224134A1
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Prior art keywords
range
group
carbon atoms
semiconducting
semiconducting material
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PCT/EP2019/062910
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French (fr)
Inventor
Yael NISENHOLZ
Amir Holtzman
Nina LIDICH
David MOCATTA
Shany NEYSHTADT
Alex RABKIN
Alex IRZH
Miriam KOOLYK
Artyom SEMYONOV
Ehud SHAVIV
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Merck Patent Gmbh
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Publication of WO2019224134A1 publication Critical patent/WO2019224134A1/en

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    • C—CHEMISTRY; METALLURGY
    • C30—CRYSTAL GROWTH
    • C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
    • C30B29/00—Single crystals or homogeneous polycrystalline material with defined structure characterised by the material or by their shape
    • C30B29/60—Single crystals or homogeneous polycrystalline material with defined structure characterised by the material or by their shape characterised by shape
    • C—CHEMISTRY; METALLURGY
    • C30—CRYSTAL GROWTH
    • C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
    • C30B29/00—Single crystals or homogeneous polycrystalline material with defined structure characterised by the material or by their shape
    • C30B29/10—Inorganic compounds or compositions
    • C30B29/46—Sulfur-, selenium- or tellurium-containing compounds
    • C30B29/48—AIIBVI compounds wherein A is Zn, Cd or Hg, and B is S, Se or Te
    • C—CHEMISTRY; METALLURGY
    • C30—CRYSTAL GROWTH
    • C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
    • C30B7/00—Single-crystal growth from solutions using solvents which are liquid at normal temperature, e.g. aqueous solutions
    • C30B7/14—Single-crystal growth from solutions using solvents which are liquid at normal temperature, e.g. aqueous solutions the crystallising materials being formed by chemical reactions in the solution

Definitions

  • the present invention relates to a semiconducting light emitting
  • nanoparticle a process for preparing a semiconducting light emitting nanoparticle; composition, formulation and use of a semiconducting light emitting nanoparticle, an optical medium; and an optical device.
  • FWFIM of the final core/shell is largely determined by the size distribution of the InP cores and this ultimately limits the FWFIM breadth.
  • InP/ZnSeS QDs fabricated with using 0.4 mmol of STBP (0.4 mmol of sulfur dissolved in 0.5 mL of TBP and 0.5 mL of ODE) and 0.2 mL of SeTOP (0.2 mmol of Se dissolved in 0.5 mL of n-trioctylphosphine and 0.5 mL of ODE) and InP quantum dot (QD)-based light-emitting diodes (QLEDs).
  • STBP 0.4 mmol of sulfur dissolved in 0.5 mL of TBP and 0.5 mL of ODE
  • SeTOP 0.2 mmol of Se dissolved in 0.5 mL of n-trioctylphosphine and 0.5 mL of ODE
  • QLEDs InP quantum dot-based light-emitting diodes
  • the inventors aimed to solve one or more of the above-mentioned problems.
  • a novel semiconducting light emitting nanoparticle comprising at least a first semiconducting material comprising at least a 1 st element of group 13 elements of the periodic table and a 2 nd element of the group 15 elements of the periodic table, and at least one shell layer comprising at least a 3 rd element of the group 12 elements of the periodic table and a 4 th element of the group 16 elements of the periodic table, wherein the nanoparticle has the self-absorption value 0.35 or less, preferably it is in the range from 0.30 to 0.01 , more preferably from 0.25 to 0.05, even more preferably from 0.23 to 0.12, and the Full Width at Half Maximum 46 nm or less, preferably it is in the range from 46 nm to 20 nm, more preferably from 40 nm to 25 nm, even more preferably from 38 nm to 30 nm.
  • the present invention relates to a semiconducting light emitting nanoparticle comprising at least a first semiconducting material comprising at least a 1 st element of group 13 elements of the periodic table and a 2 nd element of the group 15 elements of the periodic table, and at least one shell layer comprising at least a 3 rd element of the group 12 elements of the periodic table and a 4 th element of the group 16 elements of the periodic table, wherein the size distribution of the first semiconducting material is 10% or less, preferably in the range from 10% to 3%, more preferably from 8% to 4%, and the volume ratio between the shell layer and the first semiconducting material is 5 or more, preferably it is in the range from 5 to 40, more preferably it is from 10 to 30.
  • the present invention relates to a semiconducting light emitting nanoparticle comprising at least a first semiconducting material comprising at least a 1 st element of group 13 elements of the periodic table and a 2 nd element of the group 15 elements of the periodic table, and at least one shell layer wherein the shell layer is represented by following formula (II),
  • MSei-zSz (II) wherein M is Zn 2+ , or Cd 2+ , preferably M is Zn 2+ ; 0 ⁇ z ⁇ 1 , and the ratio of Se and S elements in the shell layer is in the range from 0.6 to 4.0, preferably it is in the range from 0.7 to 3.0, more preferably it is in the range from 0.8 to 2.5, even more preferably from 1.0 to 2.0.
  • the present invention relates to a new process for synthesizing a semiconducting material comprising following steps (a) to
  • step (a) mixing a semiconductor nanosized cluster and an another compound or to an another mixture of compounds at a temperature in the range from 260 to 500°C in order to get a reaction mixture, preferably said temperature is in the range from 300 to 460°C, more preferably from 330 to 430°C, even more preferably from 360 to 400°C, (b) cooling the reaction mixture to slow down or stop the growth of a first semiconducting material in step (a),
  • step (e) adjusting or keeping the temperature of the reaction mixture from step (d) in the range from 40 °C to 300 °C, preferably in the range from 50 °C to 290 °C, more preferably it is from 60 °C to 280 °C, furthermore preferably from 65 °C to 270°C to allow a growth of a first semiconducting material in the mixture, (f) optionally repeating steps (d) and (e),
  • step (g) adjusting or keeping the temperature of the reaction mixture from step (e) or (f) in the range from 200 °C to 350 °C, preferably in the range from 230 °C to 320 °C, more preferably it is from 240°C to 310 °C, furthermore preferably from 250°C to 300°C to allow growth of a first semiconducting material in the mixture,
  • step (h) cooling the reaction mixture to stop the growth of first semiconducting material in step (e) or step (f).
  • the present invention relates to a new process for synthesizing a semiconducting light emitting nanoparticle comprising following steps (i) and (j), (i) mixing a first semiconducting material, preferably it is obtained in the step (h), and at least a first cation shell precursor and a first anion shell precursor, optionally in a solvent, to form a shell layer onto the first semiconducting material, (j) quenching a shell formation of step (d), wherein said first cation shell precursor is a salt of an element of the group 12 of the periodic table and the first anion shell precursor is a source of an element of the group 16 of the periodic table, more preferably said first cation shell precursor is selected from one or more member s of the group consisting of Zn-stearate, Zn-myristate, Zn-oleate, Zn-laurate, Zn-palmitate, Zn-acetylacetonate, Cd-stearate, Cd-myri
  • MX 2 n (III) wherein M is Zn 2+ , or Cd 2+ , preferably M is Zn 2+ , X 2 is a halogen selected from the group consisting of Cl , Br and I , n is 2,
  • M is Zn 2+ , or Cd 2+ , preferably M is Zn 2+ ;
  • R 1 is a linear alkyl group having 1 to 30 carbon atoms, a branched alkyl group having 4 to 30 carbon atoms, a linear alkenyl group having 2 to 30 carbon atoms, or a branched alkenyl group having 4 to 30 carbon atoms, preferably R 1 is a linear alkyl group having 1 to 30 carbon atoms, or a linear alkenyl group having 2 to 30 carbon atoms, more preferably, R 1 is a linear alkyl group having 5 to 25 carbon atoms, or a linear alkenyl group having 6 to 25 carbon atoms, even more preferably R 1 is a linear alkyl group having 10 to 20 carbon atoms, or a linear alkenyl group having 10 to 20 carbon atoms, furthermore preferably R 1 is a linear alkenyl group having 10 to 20 carbon atoms,
  • R 2 is a linear alkyl group having 1 to 30 carbon atoms, a branched alkyl group having 4 to 30 carbon atoms, a linear alkenyl group having 2 to 30 carbon atoms, or a branched alkenyl group having 4 to 30 carbon atoms, preferably R 2 is a linear alkyl group having 1 to 30 carbon atoms, or a linear alkenyl group having 2 to 30 carbon atoms, more preferably R 2 is a linear alkyl group having 5 to 25 carbon atoms, or a linear alkenyl group having 6 to 25 carbon atoms, even more preferably R 2 is a linear alkyl group having 10 to 20 carbon atoms, or a linear alkenyl group having 10 to 20 carbon atoms, furthermore preferably R 2 is a linear alkenyl group having 10 to 20 carbon atoms, and preferably said anion shell precursor is selected from one or more members of the group consisting of Trioctylphosphine : Se,
  • Tributylphosphine Se
  • Trioctylphosphine S
  • Tributylphosphine S
  • thiols thiols
  • the present invention further relates to a semiconducting material obtainable or obtained from the process.
  • the present invention further relates to a semiconducting light emitting nanoparticle obtainable or obtained from the process.
  • the present invention also relates to composition comprising at least one semiconducting light emitting nanoparticle of the present invention, or at least one semiconducting material of the present invention, and at least one additional material, preferably the additional material is selected from the group consisting of organic light emitting materials, inorganic light emitting materials, charge transporting materials, scattering particles, and matrix materials, preferably the matrix materials are optically transparent polymers.
  • the present invention relates to formulation comprising at least one semiconducting light emitting nanoparticle, or at least one semiconducting material or the composition, and at least one solvent, preferably the solvent is selected from one or more members of the group consisting of aromatic, halogenated and aliphatic hydrocarbon solvents, more preferably selected from one or more members of the group consisting of toluene, xylene, ethers, tetrahydrofuran, chloroform, dichloromethane and heptane, purified water, ester acetates, alcohols, sulfoxides, formamides, nitrides, ketones.
  • solvent is selected from one or more members of the group consisting of aromatic, halogenated and aliphatic hydrocarbon solvents, more preferably selected from one or more members of the group consisting of toluene, xylene, ethers, tetrahydrofuran, chloroform, dichloromethane and heptane, purified water,
  • the present invention relates to use of the
  • semiconducting light emitting nanoparticle or the semiconducting material, or the composition, or the formulation in an electronic device, optical device or in a biomedical device.
  • the present invention further relates to an optical medium comprising at least one semiconducting light emitting nanoparticle, or the composition.
  • the present invention further relates to an optical device comprising at least said optical medium.
  • Figure 1 shows the results of shell coating of working example 8.
  • FIG. 2 shows the results of shell coating of working example 9.
  • Figure 3 shows the temperature profile for the reaction (recorded directly from the controller) of working example 12.
  • Figure 4 shows the EL spectrum of the ELQ-LED devices fabricated in the working example 13.
  • said semiconducting light emitting nanoparticle comprises at least a first semiconducting material comprising at least a 1 st element of group 13 elements of the periodic table and a 2 nd element of the group 15 elements of the periodic table, and at least one shell layer comprising at least a 3 rd element of the group 12 elements of the periodic table and a 4 th element of the group 16 elements of the periodic table, wherein the nanoparticle has the self-absorption value 0.35 or less, preferably it is in the range from 0.30 to 0.01 , more preferably from 0.25 to 0.05, even more preferably from 0.23 to 0.12, and the Full Width at Half Maximum (FWHM) 46 nm or less, preferably it is in the range from 46 nm to 20 nm, more preferably from 40 nm to 25 nm, even more preferably from 38 nm to 30 nm.
  • FWHM Full Width at Half Maximum
  • the nanoparticle has the trap emission 15 % or less, preferably 10% or less, more preferably it is in the range from 8% to 5%.
  • the Self-absorption value is calculated preferably according to the following procedure:
  • the optical density (hereafter“OD”) of the nanoparticles is preferably measured using Shimadzu UV-1800, double beam spectrophotometer, using toluene baseline, in the range between 350 and 800 nm.
  • the photoluminescence spectra (hereafter“PL”) of the nanoparticles is preferably measured using Jasco FP fluorimeter, in the range between 460 and 800 nm, using 450 nm excitation.
  • OD(A) and PL (A) are the measured optical density and the photoluminescence at wavelength of A.
  • OD 1 represented by the formula (X) is the optical density normalized to the optical density at 450 nm
  • ai represented by formula (XI) is the absorption corresponding to the normalized optical density.
  • the determination of the full width half maximum is made with an appropriate data base preferably comprising at least 10, more preferably at least 20 and even more preferably at least 50 data points.
  • the determination is preferably performed by using LabVIEW Software
  • width 10
  • threshold maximum value of input data divided by 5.
  • the self-absorption value of the nanoparticles represented by formula (XII) is preferably calculated based on the OD and PL measurement raw data.
  • the nanoparticle emits light having the peak maximum light emission wavelength in the range from 520nm to 700nm, preferably from 550nm to 650nm, more preferably from 580nm to 650nm.
  • the average diameter of the first semiconducting material is in the range from 1 to 4 nm, preferably it is in the range from 2.5 to 4.0, more preferably from 2.7 to 3.6.
  • the average diameter of the semiconducting nanosized light emitting particles are calculated based on 100 semiconducting light emitting nanoparticles in a TEM image created by a Tecnai G2 Spirit Twin T-12 Transmission Electron Microscope.
  • the size distribution of the first semiconducting material is 10% or less, preferably it is in the range from 10% to 3%, more preferably from 8% to 4%.
  • semiconducting material as a core is 5 or more, preferably it is in the range from 5 to 40, more preferably it is from 10 to 30.
  • said shell / core ratio (the ratio of shell / the first semiconducting material as a core) is calculated using following formula (XIII).
  • Vshell the volume of shell layer(s)
  • Vcore the volume of core
  • Mw (Total shell elements) molecular weight of total shell elements
  • Mw (Total core elements) molecular weight of total core elements
  • p (Total shell elements) density of total shell elements
  • the following elemental analysis is used in order to determine the molar ratio between group 12 element and group 13 element.
  • the semiconducting light emitting nanoparticle is dissolved in toluene and the obtained solution is diluted.
  • One droplet of the diluted solution is dripped on a Cu/C TEM grid with ultrathin amorphous carbon layer.
  • the grid is dried in vacuum at 80°C for 1.5 hours to remove the residues of the solvent as well as possible organic residues.
  • EDS measurements are carried out in STEM mode using high resolution TEM - Tecnai F20 G2 machine operating at 200kV equipped with EDAX Energy Dispersive X-Ray Spectrometer. TIA software is used for spectra acquisition and calculations and no standards are used.
  • the atomic ratio of the element of the group 12 and the element of the group 13 of the periodic table is used for the shell / core ratio calculation.
  • the calculation is carried out as follows.
  • the term“semiconductor” means a material that has electrical conductivity to a degree between that of a conductor (such as copper) and that of an insulator (such as glass) at room temperature.
  • a semiconductor is a material whose electrical conductivity increases with the temperature.
  • nanosized means the size in between 0.1 nm and 999 nm, preferably 1 nm to 150 nm, more preferbaly 3nm to 50 nm.
  • “semiconducting light emitting nanoparticle” is taken to mean that the light emitting material which size is in between 0.1 nm and 999 nm, preferably 1 nm to 150 nm, more preferbaly 3nm to 50nm, having electrical conductivity to a degree between that of a conductor (such as copper) and that of an insulator (such as glass) at room temperature, preferably, a semiconductor is a material whose electrical conductivity increases with the temperature, and the size is in between 0.1 nm and 999 nm, preferably 0,5 nm to 150 nm, more preferbaly 1 nm to 50 nm.
  • the term“size” means the average diameter of the longest axis of the semiconducting nanosized light emitting particles.
  • the semiconducting light emitting nanoparticle of the present invention is a quantum sized material.
  • the term“quantum sized” means the size of the semiconducting material itself without ligands or another surface modification, which can show the quantum confinement effect, like described in, for example, ISBN:978-3-662-44822-9.
  • the quantum sized materials can emit tunable, sharp and vivid colored light due to“quantum confinement” effect.
  • the size of the overall structures of the quantum sized material is from 1 nm to 50 nm, more preferably, it is from 1 nm to 30 nm, even more preferably, it is from 5 nm to 15 nm.
  • said first semiconducting nanosized material can be varied.
  • a semiconducting light emitting nanoparticle comprises at least a first semiconducting material comprising at least a 1 st element of group 13 elements of the periodic table and a 2 nd element of the group 15 elements of the periodic table, and at least one shell layer comprising at least a 3 rd element of the group 12 elements of the periodic table and a 4 th element of the group 16 elements of the periodic table, wherein the size distribution of the first semiconducting material is 10% or less, preferably in the range from 10% to 3%, more preferably from 8% to 4%, and the volume ratio between the shell layer and the first semiconducting material is 5 or more, preferably it is in the range from 5 to 40, more preferably it is from 10 to 30.
  • the shell layer is
  • the ratio of Se and S elements in the shell layer is in the range from 0.6 to 4.0, preferably it is in the range from 0.7 to 3.0, more preferably it is in the range from 0.8 to 2.5, even more preferably from 1.0 to 2.0.
  • a semiconducting light emitting nanoparticle comprises at least a first semiconducting material comprising at least a 1 st element of group 13 elements of the periodic table and a 2 nd element of the group 15 elements of the periodic table, and at least one shell layer, wherein the shell layer is represented by following formula (II), MSei-zSz (II) wherein M is Zn 2+ , or Cd 2+ , preferably M is Zn 2+ ; 0 ⁇ z ⁇ 1 , and the ratio of Se and S elements in the shell layer is in the range from 0.6 to 4.0, preferably it is in the range from 0.7 to 3.0, more preferably it is in the range from 0.8 to 2.5, even more preferably from 1.0 to 2.0.
  • the shell layer is represented by following formula (II), MSei-zSz (II) wherein M is Zn 2+ , or Cd 2+ , preferably M is Zn 2+ ; 0 ⁇ z ⁇ 1
  • the concentration of Se in the shell layer varies from a high concentration of the first semiconducting material side in the shell layer to a low concentration of the opposite side in the shell layer, more preferably, the concentration of S in the shell layer varies from a low concentration of first semiconducting material side of the shell layer to a higher concentration to the opposite side of the shell layer.
  • semiconducting light emitting nanoparticle further comprises a 2 nd shell layer onto said shell layer.
  • the first semiconducting material is represented by following chemical formula (I), ln (i -x-y-z-q ) Ga1 .SxZnySzSeqP (I) wherein 0 ⁇ x ⁇ 1 , 0 ⁇ y ⁇ 1 , 0 ⁇ z ⁇ 1 , 0 ⁇ q ⁇ 1 , 0 ⁇ x+y+z+q ⁇ 1.
  • the first semiconducting material has the value of the ratio of the exciton absorption peak and exciton absorption minimum of said first semiconducting material 1.6 or more at exciton wavelength 570 nm or more, preferably 1.6 or more at exciton wavelength in the range from 570 nm to 600 nm, preferably in the range 1.6 to 1.7 at exciton wavelength in the range from 565 nm to 600 nm, even more preferably in the range 1.6 to 1.7 at exciton wavelength in the range from 570nm to 580 nm.
  • the nanoparticle further comprises a zinc containing organic material selected from the group consisting of zinc carboxylates, zinc phosphonates, zinc xanthates, zinc dithiocarbamates, preferably the first semiconducting material, the shell layer and the zinc containing organic material is placed in this sequence.
  • a zinc containing organic material selected from the group consisting of zinc carboxylates, zinc phosphonates, zinc xanthates, zinc dithiocarbamates, preferably the first semiconducting material, the shell layer and the zinc containing organic material is placed in this sequence.
  • semiconducting nanosized material of the semiconducting light emitting nanoparticle, and shape of the semiconducting light emitting nanoparticle to be synthesized are not particularly limited.
  • spherical shaped, elongated shaped, star shaped, polyhedron shaped, pyramidal shaped, tetrapod shaped, tetrahedron shaped, platelet shaped, cone shaped, and irregular shaped first semiconducting nanosized material and - or a semiconducting light emitting nanoparticle can be synthesized.
  • the average diameter of the first semiconducting nanosized material is in the range from 1.5 nm to 3.5 nm.
  • said semiconducting light emitting nanoparticle has a quantum yield 10% or more, preferably in the range from 10% to 90% more preferably from 20% to 80%, even more preferably from 50% to 78%, furthermore preferably from 60% to 78%.
  • the nanoparticle preferably has a relative quantum yield of at most 90 %, more preferably at most 80 %, even more preferably at most 78 % measured by calculating the ratio of the emission counts of the nanoparticle and the dye coumarin 153 (CAS 53518-18-6) and multiplying by the QY of the dye (54.4%) measured at 25°C.
  • the nanoparticle preferably has a relative quantum yield in the range of 10 % to 90 %, more preferably in the range of 20 to 80 %, even more preferably in the range of 50 to 80 %, and even more preferably in the range of 60 to 78 % measured by calculating the ratio of the emission counts of the QD and the dye coumarin 153 (CAS 53518-18-6) and multiplying by the QY of the dye (54.4%) measured at 25°C.
  • the nanoparticle has a relative quantum yield in the range of 10 % to 90 % without any shell layer, more preferably in the range of 20 to 80 %, even more preferably in the range of 50 to 80 %, and even more preferably in the range of 60 to 78 % measured by calculating the ratio of the emission counts of the QD and the dye coumarin 153 (CAS 53518-18-6) and multiplying by the QY of the dye (54.4%) measured at 25°C.
  • the relative quantum yield is preferably calculated using absorbance and emission spectrum (excited at 350 nm), obtained using Shimadzu UV-1800 and Jasco FP-8300 spectrophotometer, using the following formula, with coumarin 153 dye in ethanol is used as a reference, with a quantum yield of 55%.
  • n the refractive index of the sample solvent (especially ethanol)
  • n ref the refractive index of the reference/standard
  • A is the percentage absorbance of the sample. The percentage of the sampling light that the sample absorbs.
  • a ref is the percentage absorbance of the reference. The percentage of the sampling light that the reference absorbs.
  • the absorbance and emission spectrum is achieved at a temperature of about 25°C.
  • the trap emission value of the nanoparticle is in the range from 0.02 to 0.15, preferably 0.05 to 0.1.
  • the trap emission value is calculated using following formula,
  • the photoluminescence spectra (hereafter " PL ” ) of the nanoparticles is measured using Jasco FP fluorimeter, in the range between 460 and 800 nm, using 450 nm excitation. wherein the symbols have the following meanings;
  • the first semiconducting material as a core is at least partially embedded in the second semiconducting material, preferably said first semiconducting material is fully embedded into the second semiconducting material.
  • said shell layer comprises at least a 1 st element of group 12 of the periodic table and a 2 nd element of group 16 of the periodic table, preferably, the 1 st element is Zn, and the 2 nd element is S, Se, or Te.
  • the second semiconducting material as a core is at least partially embedded in the second semiconducting material, preferably said first semiconducting material is fully embedded into the second semiconducting material.
  • said shell layer comprises at least a 1 st element of group 12 of the periodic table and a 2 nd element of group 16 of the periodic table, preferably, the 1 st element is Zn, and the 2 nd element is S, Se, or Te.
  • the second nd element is S, Se, or Te.
  • said shell layer is an alloyed shell layer or a graded shell layer preferably said graded shell layer is ZnS x Se y , ZnSe y Te z , or ZnS x Te z, more preferably it is ZnS x Se y .
  • the ratio of y /x is preferably larger than 0.6, more preferably in the range from 0.6 to 10, even more preferably in the range from 0.7 to 5, furthermore preferably from 1 to 3, the most preferably in the range from 1 to 2.
  • the ratio of y/z is preferably larger than 1 and more preferably larger than 2, and even more preferably larger than 4.
  • the semiconducting light emitting nanoparticle further comprises a 2 nd shell layer onto said shell layer, preferably the 2 nd shell layer comprises or a consisting of a 3 rd element of group 12 of the periodic table and a 4 th element of group 16 of the periodic table, more preferably the 3 rd element is Zn, and the 4 th element is S, Se, or Te with the proviso that the 4 th element and the 2 nd element are not the same.
  • the 2 nd shell layer is represented by following formula (V ' ),
  • the shell layer is ZnSe, ZnS x Se y , ZnSe y Te z, or ZnS x Te z with the proviso that the shell layer and the 2 nd shell layer is not the same.
  • said 2 nd shell layer can be an alloyed shell layer or a graded shell layer, preferably said graded shell layer is ZnS x Se y , ZnSe y Te z , or ZnS x Te z, more preferably it is ZnS x Se y .
  • the semiconducting light emitting nanoparticle can further comprise one or more additional shell layers onto the 2 nd shell layer as a multishell.
  • multishells stands for the stacked shell layers consisting of three or more shell layers.
  • the surface of the present invention is the surface of the present invention.
  • semiconducting light emitting nanoparticle can be over coated with one or more kinds of surface ligands. Without wishing to be bound by theory it is believed that such surface ligands may lead to disperse the nanosized fluorescent material in a solvent more easily.
  • the surface ligands in common use include phosphines and phosphine oxides such as Trioctylphosphine oxide (TOPO), Trioctylphosphine (TOP), and Tributylphosphine (TBP); phosphonic acids such as
  • Dodecylphosphonic acid DDPA
  • Tridecylphosphonic acid TDPA
  • amines such as Oleylamine, Dedecyl amine (DDA), Tetradecyl amine (TDA), Hexadecyl amine (HDA), and Octadecyl amine (ODA), Oleylamine (OLA), 1 -Octadecene (ODE), thiols such as hexadecane thiol and hexane thiol; mercapto carboxylic acids such as mercapto propionic acid and
  • the ligands can include Zn-oleate, Zn-acetate, Zn-myristate, Zn-Stearate, Zn-laurate and other Zn-carboxylates.
  • PEI Polyethylenimine
  • the present invention also relates to a process for synthesizing a semiconducting material comprising at least following steps
  • step (b) cooling the reaction mixture to slow down or stop the growth of a first semiconducting material in step (a),
  • step (c) adjusting or keeping the temperature of the reaction mixture from step (b) in the range from 40 °C to 300 °C, preferably in the range from 50 °C to
  • step (d) adding a semiconductor nanosized cluster to the reaction mixture, (e) adjusting or keeping the temperature of the reaction mixture from step (d) in the range from 40 °C to 300 °C, preferably in the range from 50 °C to 290 °C, more preferably it is from 60 °C to 280 °C, furthermore preferably from 65 °C to 270°C to allow a growth of a first semiconducting material in the mixture,
  • step (g) adjusting or keeping the temperature of the reaction mixture from step (e) or (f) in the range from 200 °C to 350 °C, preferably in the range from
  • step (h) cooling the reaction mixture to stop the growth of first semiconducting material in step (e) or step (f).
  • the process comprises steps (a), (b), (c), (d), (e), (f), (g), (h) in this sequence.
  • a cation precursor and/or an anion precursor are added in step (a) and/or step (b1 ), wherein a cation precursor is selected from one or more members of the group consisting of a Ga precursor selected from one or more members of the group consisting of GaC , GaBr3, Gab, Ga-stearate, Ga-myristate, Ga- oleate, Ga-laurate, Ga-palmitate, Ga-carboxylates, and Ga- acetylacetonate, a Zn precursor selected from one or more members of the group consisting of ZnC , ZnBr2, Zn , Zn-stearate, Zn-myristate, Zn-oleate, Zn-laurate, Zn-palmitate, Zn-carboxylates, and Zn-acetylacetonate; and an anion precursor is selected from one or more member of the group consisting of Trioctylphosphin
  • said another compound is a solvent.
  • said another compound is a solvent having the boiling point 250 °C or more, preferably in the range from 250 °C to 500 °C, more preferably in the range from 300 °C to 480 °C, even more preferably from 350 °C to 450 °C, furthermore preferably it is from 370°C to 430 °C.
  • said another compound is a solvent selected from one or more members of the group consisting of squalenes, squalanes, heptadecanes, octadecanes, octadecenes, nonadecanes, icosanes, henicosanes, docosanes, tricosanes,
  • pentatriacontane, hexatriacontane, oleylamine, and trioctylamine more preferably squalane, pentacosane, hexacosane, octacosane, nonacosane, or triacontane, even more preferably squalane, pentacosane, or
  • the temperature of the reaction mixture in step (a) is kept in the temperature range for from 1 second to 10 minutes, preferably from 5 seconds to 5 minutes, more preferably from 10 seconds to 200 seconds, more preferably from 20 seconds to 160 seconds.
  • the total amount of the inorganic part of said lll-V semiconductor nanosized clusters in step (a) is in the range from 0.1x1 O 4 to 1x1 O 3 mol%, preferably being of the amount in the range from 0.5x1 O 4 to 5x1 O 4 mol%, more preferably from 1x1 O 4 to 3x10 4 mol% of the reaction mixture.
  • the cooling rate in step (b) is in the range from 0.05 ° C/s to 50 ° C/s, preferably it is from 0.1 ° C/s to 10 ° C/s, more preferably it is from 0.2 ° C/s to 5 ° C/s, even more preferably it is from 0.5 ° C/s to 2 ° C/s.
  • the reaction mixture is cooled down to the temperature less than 220 ° C, more preferably in the rage from 220 ° C to 0 ° C, even more preferably from 210 ° C to 180 ° C, furthermore preferably from 205 ° C to 195 ° C.
  • the cooling rate in step (h) is in the range from 0.01 ° C/s to 10 ° C/s, preferably it is from 0.05 ° C/s to 5 ° C/s, more preferably it is from 0.1 ° C/s to 1 ° C/s, even more preferably it is from 0.2 ° C/s to 0.7 ° C/s.
  • the present invention also relates to a process for synthesizing a semiconducting light emitting nanoparticle comprising at least following steps (i) and (j), (i) mixing a first semiconducting material, preferably it is obtained in the step (h), and at least a first cation shell precursor and a first anion shell precursor, optionally in a solvent, to form a shell layer onto the first semiconducting material,
  • step (j) quenching a shell formation of step (d), wherein said first cation shell precursor is a salt of an element of the group 12 of the periodic table and the first anion shell precursor is a source of an element of the group 16 of the periodic table, more preferably said first cation shell precursor is selected from one or more member s of the group consisting of Zn-stearate, Zn-myristate, Zn-oleate, Zn-laurate, Zn-palmitate, Zn-acetylacetonate, Cd-stearate, Cd-myristate, Cd-oleate, Cd-laurate, Cd- palmitate, Cd-acetylacetonate a metal halogen represented by chemical formula (III) and a metal carboxylate represented by chemical formula (IV),
  • MX 2 n (III) wherein M is Zn 2+ , or Cd 2+ , preferably M is Zn 2+ , X 2 is a halogen selected from the group consisting of Cl , Br and I , n is 2,
  • M is Zn 2+ , or Cd 2+ , preferably M is Zn 2+ ;
  • R 1 is a linear alkyl group having 1 to 30 carbon atoms, a branched alkyl group having 4 to 30 carbon atoms, a linear alkenyl group having 2 to 30 carbon atoms, or a branched alkenyl group having 4 to 30 carbon atoms, preferably R 1 is a linear alkyl group having 1 to 30 carbon atoms, or a linear alkenyl group having 2 to 30 carbon atoms, more preferably, R 1 is a linear alkyl group having 5 to 25 carbon atoms, or a linear alkenyl group having 6 to 25 carbon atoms, even more preferably R 1 is a linear alkyl group having 10 to 20 carbon atoms, or a linear alkenyl group having 10 to 20 carbon atoms, furthermore preferably R 1 is a linear alkenyl group having 10 to 20 carbon atoms, R 2 is a linear alkyl group having 1 to 30 carbon atoms, a branched alkyl group having 4 to 30 carbon atom
  • the molar ratio of total shell precursors used in step (i) and total first semiconducting material used in step (i) is 6 or more, preferably in the range from 7 to 30, more preferably from 8 to 30, even more preferably from 9 to 27.
  • At least said first anion shell precursor and a second anion shell precursor are added sequentially in step (i).
  • the first anion shell precursor and a second anion shell precursor are added in step (i) and said first anion shell precursor is Trioctylphosphine : Se, or Tributylphosphine : Se, and the second anion shell precursor is Trioctylphosphine : S,
  • Tributylphosphine S, or a thiol.
  • said first semiconducting nanosized material in step (i) comprises at least a 1 st element of group 13 elements of the periodic table and a 2 nd element of the group 15 elements of the periodic table, preferably said 1 st element of the group 13 elements of the periodic table is selected from In and/or Ga, and said 2 nd element in group 15 elements of the periodic table is As, P, or Sb.
  • the first semiconducting nanosized material in step (i) further comprises a chemical element in group 12 of the periodic table selected from Zn or Cd.
  • the first semiconducting nanosized material used in step (i) comprises at least InP, such as InP, InZnP, InGaP,
  • InGaZnP, InPZnS, or InPZnSe are examples of InGaZnP, InPZnS, or InPZnSe.
  • Zn atom is directly onto the surface of the first semiconducting nanosized material or alloyed with InP.
  • the ratio between Zn and In is in the range between 0.05 and 5.
  • the first semiconducting material obtained in step (h) shows better good size distribution, better FWHM value, and/or better Max/Min ratio of the absorption spectra.
  • the first semiconducting materials is obtained in step (h) of the process of the present invention.
  • the first semiconducting nanosized material such as InP, InZnP, InGaP, InGaZnP, InPZnS, or InPZnSe
  • the first semiconducting nanosized material can be made by reacting at least one indium precursor and at least one phosphor precursor or using or a magic sized cluster.
  • said indium precursor is a metal halide represented by following chemical formula (VI), metal carboxylate represented by following chemical formula (VII), or a combination of these
  • said phosphor precursor is an amino phosphine represented by following chemical formula (VIII), tris trimethyl silyl phosphine, or a combination of these, lnX 1 3 (VI)
  • X 1 is a halogen selected from the group consisting of Cl , Br and I ,
  • R 3 is a linear alkyl group having 1 to 30 carbon atoms, a branched alkyl group having 4 to 30 carbon atoms, a linear alkenyl group having 2 to 30 carbon atoms, or a branched alkenyl group having 4 to 30 carbon atoms, preferably R 3 is a linear alkyl group having 1 to 30 carbon atoms, or a linear alkenyl group having 2 to 30 carbon atoms, more preferably, R 3 is a linear alkyl group having 5 to 25 carbon atoms, or a linear alkenyl group having 6 to 25 carbon atoms, even more preferably R 3 is a linear alkyl group having 10 to 20 carbon atoms, or a linear alkenyl group having 10 to 20 carbon atoms, furthermore preferably R 3 is a linear alkenyl group having 10 to 20 carbon atoms,
  • R 4 and R 5 are at each occurrence, independently or dependently, a hydrogen atom or a linear alkyl group having 1 to 25 carbon atoms or a linear alkenyl group having 2 to 25 carbon atoms, preferably a linear alkyl group having 1 to 10 carbon atoms, more preferably a linear alkyl group having 2 to 4 carbon atoms, even more preferably a linear alkyl group having 2 carbon atoms, more preferably said zinc salt is represented by following chemical formula (IX),
  • X 2 is a halogen selected from the group consisting of Cl , Br and I , n is 2.
  • said a lll-V magic sized cluster can be selected from the group consisting of InP, InAs, InSb, GaP, GaAs, and GaSb, magic sized clusters (MSC), preferably InP magic sized cluster (MSC InP), more preferably, it is ln 37 P2o(0 2 CR 1 ) 5i , wherein said O2CR 1 of said ln37P2o(02CR 1 )si is -
  • 02CCH2Phenyl or a substituted or unsubstituted fatty acid such as hexanoate, heptanoate, octanoate, nonanoate, decanoate, undecanoate, dodecanoate, tridecanoate, tetradecanoate, pentadecanoate,
  • Such InP magic sized clusters (MSCs) as single source precursors (SSP) can be fabricated as described in D. Gary et al., Chem. Mater., 2015, 1432.
  • said solvent in step (i) is selected from one or more members of the group consisting of squalenes, squalanes, heptadecanes, octadecanes, octadecenes, nonadecanes, icosanes, henicosanes, docosanes, tricosanes, pentacosanes,
  • alkyl chain lengths of said solvent can be C1 to C30, and the chain can be linear or branched.
  • a cation precursor for formation of the second semiconducting nanosized material as a shell layer one or more of known cation precursors for shell layer synthesis comprising group 12 element of the periodic table or 13 elements of the periodic table can be used preferably.
  • the metal halides and the cation precursor can be mixed, or, the metal halide can be used as a single cation precursor instead of the cation precursor which is mentioned in the column of cation precursors for formation of the second semiconducting material, if necessary.
  • an anion precursor for formation of the second semiconducting material shell layer coating
  • known anion precursor for shell layer synthesis comprising a group 16 element of the periodic table
  • a first and a second anion precursor for formation of the second semiconducting material can be selected from one or more members of the group consisting of Se anion: Se, Se-trioctylphopshine, Se- tributylphosphine, Se-oleylamine complex, Selenourea, Se-octadecene complex, Se-octadecene suspension, S anion and thiols such as
  • octanethiol dodecanthiol, ter-doedecanthiol,: S, S-trioctylphopshine, S- tributylphosphine, S-oleylamine complex, Selenourea, S-octadecene complex, and S-octadecene suspension, Te anion: Te, Te- trioctylphopshine, Te- tributylphosphine, Te-oleylamine complex,
  • At least said first anion precursor and a second anion precursor are added simultaneously in the process of formation of the second semiconducting material, preferably said first anion precursor is selected from the group consisting of Se anion: Se, Se-trioctylphopshine, Se- tributylphosphine, Se-oleylamine complex, Selenourea, Se-octadecene complex, and Se-octadecene suspension, and the second anion shell precursor is selected from the group consisting of S anion: S, S-trioctylphopshine, S- tributylphosphine, S-oleylamine complex, Selenourea, S-octadecene complex, and S-octadecene suspension, Te anion: Te, Te-trioctylphopshine, Te- tributylphosphine, Te-oleylamine complex, Telenourea
  • At least said first anion precursor and a second anion precursor are added sequentially in step of the formation of the second semiconducting material, preferably said first anion precursor is selected from the group consisting of Se anion: Se, Se- trioctylphopshine, Se- tributylphosphine, Se-oleylamine complex,
  • the second anion precursor is selected from the group consisting of S anion: S, S-trioctylphopshine, S- tributylphosphine, S-oleylamine complex, Selenourea, S-octadecene complex, and S-octadecene suspension, Te anion: Te, Te-trioctylphopshine, Te- tributylphosphine, Te-oleylamine complex, Telenourea, Te-octadecene complex, and Te-octadecene suspension.
  • the volume ratio between the first semiconducting nanosized material and the shell is more preferably controlled.
  • step (i) is carried out at 250 °C or more, preferably, it is in the range from 250°C to 350°C, more preferably, from 280°C to 320°C to realize better shell / first semiconducting nanosized material volume ratio and lower self-absorption value of the semiconducting light emitting nanoparticle.
  • this process can also control the crystallinity of the shell layer. For example, it is believed that highly crystalline ZnSe shell is obtained using this process. -Treatment process
  • the process further comprises following step (k) before step (i), (k) subjecting said a first semiconducting material to a surface treatment with a metal halide represented by following chemical formula (III), MX 2 n (III) wherein M is Zn 2+ , or Cd 2+ , preferably M is Zn 2+ , X 2 is a halogen selected from the group consisting of Cl , Br and I , n is 2.
  • a metal halide represented by following chemical formula (III), MX 2 n (III) wherein M is Zn 2+ , or Cd 2+ , preferably M is Zn 2+ , X 2 is a halogen selected from the group consisting of Cl , Br and I , n is 2.
  • the step (k) is carried out at the temperature in the range from 150°C to 350°C, preferably in the range from 200°C to 320 °C, more preferably in the range from 250°C to 300°C, even more preferably from 250°C to 280°C.
  • the treatment time of step (k) is in the range from 10 minutes to 10 hours, preferably from 20 minutes to 4 hours, more preferably 30 minutes to 3 hours.
  • the total molar ratio between the amount of the metal halide in step (k) and the amount of the first semiconducting material is in the range from 500 to 50.000, preferably from 1.000 to 20.000, more preferably from 2.000 to 10.000.
  • the total molar ratio between the amount of the metal halide in step (k) and the amount of InP core as the first semiconducting material is in the range from 500 to 50.000, preferably from 1.000 to 20.000, more preferably from 2.000 to 10.000.
  • step (k) is carried out in a solution comprising at least one solvent selected from one or more members of the group consisting of squalenes, squalanes, heptadecanes, octadecanes, octadecenes, nonadecanes, icosanes, henicosanes, docosanes, tricosanes, pentacosanes, hexacosanes, octacosanes, nonacosanes, triacontanes, hentriacontanes, dotriacontanes, tritriacontanes, tetratriacontanes, pentatriacontanes, hexatriacontanes, oleylamines, and trioctylamines, with preferably being of squalene, squalane, heptadecane, oc
  • the process can optionally comprise following cleaning step (I), preferably cleaning step (I) is carried out after step (k) before step (i),
  • cleaning the first semiconducting material with a cleaning solution preferably said cleaning solution comprises at least one solvent selected from one or more members of the group consisting of ketones, such as, methyl ethyl ketone, acetone, methyl amyl ketone, methyl isobutyl ketone, and cyclohexanone; alcohols, such as, methanol, ethanol, propanol, butanol, hexanol, cyclo hexanol, ethylene glycol; hexane; chloroform;
  • ketones such as, methyl ethyl ketone, acetone, methyl amyl ketone, methyl isobutyl ketone, and cyclohexanone
  • alcohols such as, methanol, ethanol, propanol, butanol, hexanol, cyclo hexanol, ethylene glycol; hexane; chloroform;
  • xylene and toluene preferably alcohol and toluene, more preferably ethanol and toluene.
  • step (I) is carried out at the temperature in the range of from 0°C to 100°C, preferably from 5 to 60°C, more preferably from 10 to 40°C to clean the first semiconducting
  • the step (I) comprises following step (11 ),
  • step (11 ) making a mixture solution by mixing the obtained solution from step (h) and a cleaning solution of the present invention, to make a suspension in the mixture solution and to separate unreacted first semiconducting nanosized material precursors and ligands from the suspension.
  • step (I) further comprises following step (I2),
  • the solvent in step (I2) is selected from the solvent described in the section of " Solvent ” above.
  • the cleaning solution for step (k) comprises at least one solvent selected from one or more members of the group consisting of ketones, such as, methyl ethyl ketone, acetone, methyl amyl ketone, methyl isobutyl ketone, and cyclohexanone; alcohols, such as, methanol, ethanol, propanol, butanol, hexanol, cyclo hexanol, ethylene glycol; hexane; chloroform; acetonitrile; xylene and toluene.
  • ketones such as, methyl ethyl ketone, acetone, methyl amyl ketone, methyl isobutyl ketone, and cyclohexanone
  • alcohols such as, methanol, ethanol, propanol, butanol, hexanol, cyclo hexanol, ethylene glycol; hexane; chloroform;
  • the cleaning solution is selected from one or more members of the group consisting of ketones, such as, methyl ethyl ketone, acetone, methyl amyl ketone, methyl isobutyl ketone, and cyclohexanone; alcohols, such as, methanol, ethanol, propanol, butanol, hexanol, cyclo hexanol, ethylene glycol; hexane;
  • ketones such as, methyl ethyl ketone, acetone, methyl amyl ketone, methyl isobutyl ketone, and cyclohexanone
  • alcohols such as, methanol, ethanol, propanol, butanol, hexanol, cyclo hexanol, ethylene glycol; hexane;
  • cleaning solution comprises one or more of alcohols is used.
  • the cleaning solution contains one or more of alcohols selected from the group consisting of acetonitrile, methanol, ethanol, propanol, butanol, and hexanol, and one more solution selected from xylene or toluene to remove unreacted first semiconducting nanosized material precursors from the solution obtained in step (h) and remove the ligands leftovers in the solution effectively.
  • the cleaning solution contains one or more of alcohols selected from methanol, ethanol, propanol, and butanol, and toluene.
  • the mixing ratio of alcohols and toluene or xylene can be in the range from 1 :1 - 20:1 in a molar ratio. Preferably it is from 5:1 to 10:1 , to remove unreacted first semiconducting nanosized material precursors from the solution obtained in step (h) and to remove the ligands leftovers in the solution.
  • the cleaning solution removes the extra ligands and the un reacted precursor.
  • the process further comprises following step (m), preferably step (m) is carried out after step (i), more preferably after step (I).
  • step (m) Irradiating light with a peak light wavelength in the range from 300 to 650 nm to the semiconducting light emitting nanoparticle, preferably in the range from 320 to 520nm, more preferably from 350nm to 500 nm, even more preferably at 360nm to 470nm, preferably in the presence of zinc containing organic material selected from one or more member of the group consisting of zinc carboxylates, zinc phosphonates, zinc xanthates, and zinc dithiocarbamates.
  • the intention of the light irradiation is in the range from 0,025 to 1 watt/cm 2 , preferably it is in the range from 0.05 to 0.5 watt/cm 2 .
  • At least one of the steps of the process is carried out in an inert condition, such as ish atmosphere, preferably all the steps are carried out in said inert condition.
  • the present invention also relates to a semiconducting material obtainable or obtained from the process comprising steps (a) to (h) of the present invention.
  • the present invention also relates to a semiconducting nanoparticle obtainable or obtained from the process comprising steps of (i) and (j) of the present invention.
  • the value of the ratio of the exciton absorption peak and the exciton absorption minimum of said semiconductor nanoparticle is 1.3 or more, preferably is 1.6 or more, more preferably 1.7 or more, even more preferably 1.8 or more.
  • composition in another aspect, also relates to composition comprising at least one semiconducting light emitting nanoparticle of the present invention, or at least one semiconducting material of the present invention, and at least one additional material, preferably the additional material is selected from the group consisting of organic light emitting materials, inorganic light emitting materials, charge transporting materials, scattering particles, and matrix materials, preferably the matrix materials are optically transparent polymers.
  • said activator can be selected from the group consisting of Sc 3+ ,Y 3+ , La 3+ , Ce 3+ , Pr 3+ , Nd 3+ , Pm 3+ , Sm 3+ , Eu 3+ , Gd 3+ , Tb 3+ , Dy 3+ , Ho 3+ , Er 3+ , Tm 3+ , Yb 3+ , Lu 3+ , Bi 3+ , Pb 2+ , Mn 2+ , Yb 2+ , Sm 2+ , Eu 2+ , Dy 2+ , Ho 2+ and a combination of any of these, and said inorganic fluorescent material can be selected from the group consisting of sulfides, thiogallates, nitrides, oxynitrides, silicate, aluminates, apatites, borates, oxides, phosphates, halo phosphates, sulfates, tungstenates, tantalates, vanadates, mo
  • Such suitable inorganic fluorescent materials described above can be well known phosphors including nanosized phosphors, quantum sized materials like mentioned in the phosphor handbook, 2 nd edition (CRC Press, 2006), pp. 155 - pp. 338 (W.M.Yen, S.Shionoya and FI .Yamamoto),
  • any type of publicly known materials can be used preferably.
  • organic fluorescent materials organic host materials, organic dyes, organic electron transporting materials, organic metal complexes, and organic hole transporting materials.
  • small particles of inorganic oxides such as S1O2, Sn02, CuO, CoO, AI2O3 T1O2, Fe203, Y2O3, ZnO, MgO;
  • organic particles such as polymerized polystyrene, polymerized PMMA; inorganic hollow oxides such as hollow silica or a combination of any of these; can be used preferably.
  • - Matrix material organic particles such as polymerized polystyrene, polymerized PMMA; inorganic hollow oxides such as hollow silica or a combination of any of these; can be used preferably.
  • the term“transparent” means at least around 60 % of incident light transmit at the thickness used in an optical medium and at a wavelength or a range of wavelength used during operation of an optical medium. Preferably, it is over 70 %, more preferably, over 75%, the most preferably, it is over 80 %.
  • any type of publicly known transparent matrix material described in for example, WO 2016/134820A can be used.
  • the transparent matrix material can be a transparent polymer.
  • the term“polymer” means a material having a repeating unit and having the weight average molecular weight (Mw) 1000 g/mol, or more.
  • Mw weight average molecular weight
  • the glass transition temperature (Tg) of the transparent polymer is 70 °C or more and 250 °C or less.
  • Tg is measured based on changes in the heat capacity observed in
  • poly(meth)acrylates epoxys, polyurethanes, polysiloxanes
  • epoxys epoxys
  • polyurethanes polysiloxanes
  • the weight average molecular weight (Mw) of the polymer as the transparent matrix material is in the range from 1 ,000 to 300,000 g/mol, more preferably it is from 10,000 to 250,000 g/mol.
  • the composition comprises a plural of the light emitting nanoparticles and/or a plural of the semiconducting materials.
  • the present invention relates to formulation comprising at least one semiconducting light emitting nanoparticle or the composition of the present invention
  • the solvent is selected from one or more members of the group consisting of aromatic, halogenated and aliphatic hydrocarbon solvents, more preferably selected from one or more members of the group consisting of toluene, xylene, ethers, tetrahydrofuran, chloroform, dichloromethane and heptane, purified water, ester acetates, alcohols, sulfoxides, formamides, nitrides, ketones.
  • the amount of the solvent in the formulation can be freely controlled according to the method of coating the composition.
  • the composition if the composition is to be spray-coated, it can contain the solvent in an amount of 90 wt. % or more.
  • the content of the solvent is normally 60 wt. % or more, preferably 70 wt. % or more.
  • the formulation comprises a plural of the semiconducting light emitting nanoparticles and/or a plural of the semiconducting materials.
  • the present invention relates to use of the
  • the present invention further relates to an optical medium comprising at least one semiconducting light emitting nanoparticle of the present invention, or at least one semiconducting material of the present invention, or the composition.
  • the optical medium can be an optical sheet, for example, a color filter, color conversion film, remote phosphor tape, or another film or filter.
  • sheet includes film and / or layer like structured mediums.
  • the optical medium comprises an anode and a cathode, and at least one organic layer comprising at least one light emitting nanoparticle or the composition of the present invention, preferably said one organic layer is a light emission layer, more preferably the medium further comprises one or more additional layers selected from the group consisting of hole injection layers, hole transporting layers, electron blocking layers, hole blocking layers, electron blocking layers, and electron injection layers.
  • any kinds of publicly available inorganic, and/or organic materials for hole injection layers, hole transporting layers, electron blocking layers, light emission layers, hole blocking layers, electron blocking layers, and electron injection layers can be used preferably, like as described in WO 2018/024719 A1 , US2016/233444 A2, US7754841 B, WO 2004/037887 and WO 2010/097155.
  • the optical medium comprises a plural of the light emitting nanoparticles and/or a plural of the semiconducting materials.
  • the anode and the cathode of the optical medium sandwich the organic layer.
  • the organic layer comprises at least one light emitting nanoparticle of the present invention, and a host material, preferably the host material is an organic host material.
  • the optical medium can comprise at least a substrate
  • an anode such as ITO layer
  • HTL hole transporting layer
  • EML emission layer
  • EIL electron injection layer
  • ETL electron transporting layer
  • said emission layer comprises at least one light emitting
  • the invention further relates to an optical device comprising the optical medium.
  • the optical device can be a liquid crystal display device (LCD), Organic Light Emitting Diode (OLED), backlight unit for an optical display, Light Emitting Diode device (LED), Micro Electro Mechanical Systems (here in after“MEMS”), electro wetting display, or an electrophoretic display, a lighting device, and / or a solar cell.
  • LCD liquid crystal display device
  • OLED Organic Light Emitting Diode
  • LED Light Emitting Diode device
  • MEMS Micro Electro Mechanical Systems
  • electro wetting display or an electrophoretic display
  • a lighting device and / or a solar cell.
  • said optical device configured so that the optical device can emit light, and it comprises an optical medium including at least a substrate;
  • an anode such as ITO layer
  • HTL hole transporting layer
  • EML emission layer
  • EIL electron injection layer
  • ETL electron transporting layer
  • said emission layer comprises at least one light emitting
  • optical layer such as glass substrate, a color filter, polarizer such as a linear polarizer, circular polarizer, antireflection layer and light direction changing layer.
  • the present invention provides one or more of following effects
  • a semiconducting light emitting nanoparticle comprising at least a first semiconducting material comprising at least a 1 st element of group 13 elements of the periodic table and a 2 nd element of the group 15 elements of the periodic table, and at least one shell layer comprising at least a 3 rd element of the group 12 elements of the periodic table and a 4 th element of the group 16 elements of the periodic table, wherein the nanoparticle has the self-absorption value 0.35 or less, preferably it is in the range from 0.30 to 0.01 , more preferably from 0.25 to 0.05, even more preferably from 0.23 to 0.12, and the Full Width at Half Maximum 46 nm or less, preferably it is in the range from 46 nm to 20 nm, more preferably from 40 nm to 25 nm, even more preferably from 38 nm to 30 nm.
  • the nanoparticle according to embodiment 1 wherein the nanoparticle has the trap emission 15 % or less, preferably
  • nanoparticle emits light having the peak maximum light emission
  • a semiconducting light emitting nanoparticle comprising at least a first semiconducting material comprising at least a 1 st element of group 13 elements of the periodic table and a 2 nd element of the group 15 elements of the periodic table, and at least one shell layer comprising at least a 3 rd element of the group 12 elements of the periodic table and a 4 th element of the group 16 elements of the periodic table, wherein the size distribution of the first semiconducting material is 10% or less, preferably in the range from 10% to 3%, more preferably from 8% to 4%, and the volume ratio between the shell layer and the first semiconducting material is 5 or more, preferably it is in the range from 5 to 40, more preferably it is from 10 to 30.
  • a semiconducting light emitting nanoparticle comprising at least a first semiconducting material comprising at least a 1 st element of group 13 elements of the periodic table and a 2 nd element of the group 15 elements of the periodic table, and at least one shell layer, wherein the shell layer is represented by following formula (II),
  • MSei-zSz (I I) wherein M is Zn 2+ , or Cd 2+ , preferably M is Zn 2+ ; 0 ⁇ z ⁇ 1 , and the ratio of Se and S elements in the shell layer is in the range from 0.6 to 4.0, preferably it is in the range from 0.7 to 3.0, more preferably it is in the range from 0.8 to 2.5, even more preferably from 1.0 to 2.0. 11.
  • concentration of the opposite side in the shell layer more preferably, the concentration of S in the shell layer varies from a low concentration of first semiconducting material side of the shell layer to a higher concentration to the opposite side of the shell layer.
  • nanoparticle according to any one of embodiments 1 to 11 , wherein the semiconducting light emitting nanoparticle further comprises a 2 nd shell layer onto said shell layer.
  • semiconducting material 1.6 to 3 at exciton wavelength 570 nm or more, preferably 1.6 to 2.5 at exciton wavelength in the range from 570 nm to 600 nm, preferably in the range 1.6 to 2 at exciton wavelength in the range from 565 nm to 600 nm, even more preferably in the range 1.6 to 1.8 at exciton wavelength in the range from 570nm to 580 nm.
  • a zinc containing organic material selected from the group consisting of zinc carboxylates, zinc phosphonates, zinc xanthates, zinc dithiocarbamates, preferably the first semiconducting material, the shell layer and the zinc containing organic material is placed in this sequence.
  • a process for synthesizing a semiconducting nanoparticle comprising following steps (a) to (h),
  • step (b) cooling the reaction mixture to slow down or stop the growth of a first semiconducting material in step (a),
  • step (c) adjusting or keeping the temperature of the reaction mixture from step (b) in the range from 40 °C to 300 °C, preferably in the range from 50 °C to 290 °C, more preferably from 60 °C to 280 °C, furthermore preferably from 65 °C to 270°C to allow a growth of a first semiconducting material in the mixture, (d) adding a semiconductor nanosized cluster to the reaction mixture,
  • step (h) cooling the reaction mixture to stop the growth of first semiconducting material in step (e) or step (f).
  • said another compound is a solvent selected from one or more members of the group consisting of squalenes, squalanes, heptadecanes, octadecanes, octadecenes, nonadecanes, icosanes, henicosanes, docosanes, tricosanes, pentacosanes, hexacosanes, octacosanes, nonacosanes, triacontanes, hentriacontanes, dotriacontanes, tritriacontanes,
  • tetratriacontanes pentatriacontanes, hexatriacontanes, oleylamines, and trioctylamines, with preferably being of squalene, squalane, heptadecane, octadecane, octadecene, nonadecane, icosane, henicosane, docosane, tricosane, pentacosane, hexacosane, octacosane, nonacosane,
  • triacontane triacontane, hentriacontane, dotriacontane, tritriacontane, tetratriacontane, pentatriacontane, hexatriacontane, oleylamine, and trioctylamine, more preferably squalane, pentacosane, hexacosane, octacosane, nonacosane, or triacontane, even more preferably squalane, pentacosane, or
  • step (a) The process according to any one of embodiments 16 to 19, wherein the temperature of the reaction mixture in step (a) is kept in the temperature range for from 1 second to 10 minutes, preferably from 5 seconds to 5 minutes, more preferably from 10 seconds to 200 seconds, more preferably from 20 seconds to 160 seconds.
  • step (a) The process according to any one of embodiments 16 to 20, wherein the total amount of the inorganic part of said lll-V semiconductor nanosized clusters in step (a) is in the range from 0.1x1 O 4 to 1x1 O 3 mol%, preferably being of the amount in the range from 0.5x1 O 4 to 5x1 O 4 mol%, more preferably from 1x1 O 4 to 3x1 O 4 mol% of the reaction mixture.
  • step (b) is in the range from 0.05 ° C/s to 50 ° C/s, preferably it is from 0.1 ° C/s to 10 ° C/s, more preferably it is from 0.2 ° C/s to 5 ° C/s, even more preferably it is from 0.5 ° C/s to 2 ° C/s. 23.
  • step (h) is in the range from 0.01 ° C/s to 10 ° C/s, preferably it is from 0.05 ° C/s to 5 ° C/s, more preferably it is from 0.1 ° C/s to 1 ° C/s, even more preferably it is from 0.2 ° C/s to 0.7 ° C/s.
  • a process for synthesizing a semiconducting light emitting nanoparticle comprising following steps (i) and (j), (i) mixing a first semiconducting material, preferably it is obtained in the step (h) according to any one of claims 16 to 23, and at least a first cation shell precursor and a first anion shell precursor, optionally in a solvent, to form a shell layer onto the first semiconducting material, (j) quenching a shell formation of step (d), wherein said first cation shell precursor is a salt of an element of the group 12 of the periodic table and the first anion shell precursor is a source of an element of the group 16 of the periodic table, more preferably said first cation shell precursor is selected from one or more member s of the group consisting of Zn-stearate, Zn-myristate, Zn-oleate, Zn-laurate, Zn-palmitate, Zn-acetylacetonate, Cd-stearate, Cd-myristate
  • MX 2 n (III) wherein M is Zn 2+ , or Cd 2+ , preferably M is Zn 2+ , X 2 is a halogen selected from the group consisting of Cl , Br and I , n is 2,
  • M is Zn 2+ , or Cd 2+ , preferably M is Zn 2+ ;
  • R 1 is a linear alkyl group having 1 to 30 carbon atoms, a branched alkyl group having 4 to 30 carbon atoms, a linear alkenyl group having 2 to 30 carbon atoms, or a branched alkenyl group having 4 to 30 carbon atoms, preferably R 1 is a linear alkyl group having 1 to 30 carbon atoms, or a linear alkenyl group having 2 to 30 carbon atoms, more preferably, R 1 is a linear alkyl group having 5 to 25 carbon atoms, or a linear alkenyl group having 6 to 25 carbon atoms, even more preferably R 1 is a linear alkyl group having 10 to 20 carbon atoms, or a linear alkenyl group having 10 to 20 carbon atoms, furthermore preferably R 1 is a linear alkenyl group having 10 to 20 carbon atoms,
  • R 2 is a linear alkyl group having 1 to 30 carbon atoms, a branched alkyl group having 4 to 30 carbon atoms, a linear alkenyl group having 2 to 30 carbon atoms, or a branched alkenyl group having 4 to 30 carbon atoms, preferably R 2 is a linear alkyl group having 1 to 30 carbon atoms, or a linear alkenyl group having 2 to 30 carbon atoms, more preferably R 2 is a linear alkyl group having 5 to 25 carbon atoms, or a linear alkenyl group having 6 to 25 carbon atoms, even more preferably R 2 is a linear alkyl group having 10 to 20 carbon atoms, or a linear alkenyl group having 10 to 20 carbon atoms, furthermore preferably R 2 is a linear alkenyl group having 10 to 20 carbon atoms, and preferably said anion shell precursor is selected from one or more members of the group consisting of Trioctylphosphine : Se,
  • Tributylphosphine Se, Trioctylphosphine : S, Tributylphosphine : S, and thiols. 25.
  • the molar ratio of total shell precursors used in step (i) and total first semiconducting material used in step (i) is 6 or more, preferably in the range from 7 to 30, more preferably from 8 to 30, even more preferably from 9 to 27.
  • Tributylphosphine Se
  • the second anion shell precursor is
  • Trioctylphosphine S
  • Tributylphosphine S
  • or a thiol Trioctylphosphine
  • MX 2 n (III) wherein M is Zn 2+ , or Cd 2+ , preferably M is Zn 2+ , X 2 is a halogen selected from the group consisting of Cl , Br and I , n is 2.
  • step (k) is carried out at the temperature in the range from 150°C to
  • 350°C preferably in the range from 200°C to 320 °C, more preferably in the range from 250°C to 300°C, even more preferably from 250°C to 280°C.
  • step (k) is in the range from 10 minutes to 10 hours, preferably from 20 minutes to 4 hours, more preferably 30 minutes to 3 hours.
  • step (k) wherein the treatment time of step (k) wherein the total molar ratio between the amount of the metal halide in step (k) and the amount of the first
  • semiconducting material is in the range from 500 to 50.000, preferably from 1.000 to 20.000, more preferably from 2.000 to 10.000.
  • step (k) is carried out in a solution comprising at least one solvent selected from one or more members of the group consisting of squalenes, squalanes, heptadecanes, octadecanes, octadecenes, nonadecanes, icosanes, henicosanes, docosanes, tricosanes, pentacosanes,
  • cleaning the first semiconducting material with a cleaning solution comprises at least one solvent selected from one or more members of the group consisting of ketones, such as, methyl ethyl ketone, acetone, methyl amyl ketone, methyl isobutyl ketone, and cyclohexanone; alcohols, such as, methanol, ethanol, propanol, butanol, hexanol, cyclo hexanol, ethylene glycol; hexane; chloroform; xylene and toluene, preferably alcohol and toluene, more preferably ethanol and toluene.
  • ketones such as, methyl ethyl ketone, acetone, methyl amyl ketone, methyl isobutyl ketone, and cyclohexanone
  • alcohols such as, methanol, ethanol, propanol, butanol, hexanol, cyclo he
  • a semiconducting material obtainable or obtained from the process according to any one of embodiments 16 to 23.
  • nanoparticle according to embodiment 37 wherein the value of the ratio of the exciton absorption peak and the exciton absorption minimum of said semiconductor nanoparticle, is 1.3 or more, preferably is 1.6 or more, more preferably 1.7 or more, even more preferably 1.8 or more.
  • a semiconducting light emitting nanoparticle obtainable or obtained from the process according to any one of embodiments 24 to 36. 40.
  • a composition comprising at least one semiconducting light emitting nanoparticle according to any one of embodiments 1 to 15, 39, or at least one semiconducting material of embodiment 37 or 38, and at least one additional material, preferably the additional material is selected from the group consisting of organic light emitting materials, inorganic light emitting materials, charge transporting materials, scattering particles, host materials, nanosized plasmonic particles, photo initiators, and matrix materials.
  • Formulation comprising at least one semiconducting light emitting nanoparticle according to any one of embodiments 1 to 15, 39, or at least one semiconducting material of embodiment 37 or 38, or a composition according to embodiment 40, and at least one solvent, preferably the solvent is selected from one or more members of the group consisting of aromatic, halogenated and aliphatic hydrocarbon solvents, more preferably selected from one or more members of the group consisting of toluene, xylene, ethers,
  • An optical medium comprising at least one semiconducting light emitting nanoparticle according to any one of embodiments 1 to 15, 39, or at least one semiconducting material of embodiment 37 or 38, or a composition according to embodiment 40.
  • the optical medium of embodiment 43 comprising an anode and a cathode, and at least one organic layer comprising at least one light emitting nanoparticle according to any one of embodiments 1 to 15, 39, or at least one semiconducting material of embodiment 37 or 38, or a composition according to embodiment 40, preferably said one organic layer is a light emission layer, more preferably the medium further comprises one or more layers selected from the group consisting of hole injection layers, hole transporting layers, electron blocking layers, hole blocking layers, electron blocking layers, and electron injection layers.
  • An optical device comprising at least said optical medium according to any one of embodiments 43 to 45.
  • the flask is cooled down.
  • the mantle is then brought back and the flaks is heated to 70°C.
  • 0.2 ml of 6.3-1 O 6 M MSCs solution in squalane is added to the flask at a rate of 0.2 ml/sec.
  • the flask is heated to 250 C. After 25 minutes the mantle is removed and the flask is cooled to room temperature.
  • the MSCs are synthesized as described in the literature 7 D. Gary et al., Chem. Mater., 2015, 1432.
  • a 50ml_, 14/20, four-neck round-bottom flask equipped with a reflux condenser is evacuated, and 12 ml of distilled squalane is injected into it.
  • the apparatus is evacuated with stirring (and heated to 375°C under argon. Two solutions are prepared from the cleaned clusters solution:
  • Injection solutions ml solution of the MSCs in distilled squalene is prepared, with a concentration of 6.3E-4M.
  • InP QDs are formed with exciton at 598nm and max/min of 1.49.
  • a 50ml_, 14/20, four-neck round-bottom flask equipped with a reflux condenser is evacuated, and 10 ml of distilled squalane is injected into it.
  • the apparatus is evacuated with stirring (pressure is lowered from 300mtorr to200 mTorr during 1 hour) and heated to 375°C under argon.
  • a solution of MSCs with a concentration of 3.15x10 04 M is prepared in distilled squalene. 4 ml (1.26E-06 moles) of this solution is injected to the flask at 375°C, using a 16 gauge needle and 6 ml syringe;
  • the mantle is removed and the flask is cooled to 200°C by blowing air with a fan. The mantle is then brought back and the flask is heated to 265°C.
  • InP QDs are formed with exciton at 593nm and max/min of 1.3.
  • Working Example 8 ZnSe shell synthesis on InP cores having exciton CWL of 552 nm.
  • the InP cores had an exciton with a CWL of 552 nm and max/min exciton peak optical density ratio of 1.32.
  • the final solution is cleaned with a mixture of anhydrous toluene and ethanol (ratio
  • SSP InP cores 75mg of Zn(CI)2 and 1 amount (0.28mL of 2M TOP:Se) of anion shell precursor are added to SSP InP cores.
  • the solution is heated by steps to 220C, followed by one injection of cation (1.1 mL of 0.4M Zn(acetate)-0.8M oleylamine in ODE) shell precursor. Afterwards, the solution is heated to 240C, followed by one injection of anion (0.19mL of 2M TOP:Se) shell precursor.
  • the solution is heated to 280C, followed by one injection of cation (1.1 mL of 0.4M Zn(acetate)-0.8M oleylamine in ODE) shell precursor.
  • the solution is heated to 320C, followed by one injection of anion (0.19mL of 2M TOP:Se) shell precursor, and later an additional injection of cation (1.1 mL of 0.4M Zn(acetate)-0.8M oleylamine in ODE) shell precursor.
  • Table 4 shows the anion / cation precursor injections.
  • This example differs from example 8 since by the exciton CWL and max/min exciton peak optical density ratio of the InP core, which are 598 nm and 1.3 in example 9 as opposed to 552 nm and 1.32 in example 8.
  • the shell synthesis steps are identical to example 8.
  • Figure2 presents the results of shell coating.
  • This example differs from example 8 since by the exciton CWL and max/min exciton peak optical density ratio of the InP core, which are 593 nm and 1.3 in example 10 as opposed to 552 nm and 1.32 in example 8.
  • the shell synthesis steps are identical to example 8.
  • Table 5 lists the values of QY, FWHM and trap emission for both examples described.
  • squalane In a nitrogen filled glove-box, 120 ml of squalane (batch SQLVAC2) is transferred into a 500 ml_, 24/40, four-neck round-bottom flask equipped with a stop-cock tap. (The squalane used is previously put under reduced pressure 200 mTorr at a temperature of 90C for 2hrs.) The flask + tap are connected to a reflux condenser and the apparatus is evacuated with stirring at 90 °C (pressure is 100 mTorr) and heated to 375 °C. Two solutions are prepared from a cleaned clusters solution. The crude cluster solution is cleaned by 5 successive precipitation cycles using toluene, acetonitrile and centrifugation.
  • the mantle is removed and the flask is cooled to 200°C using an air gun. The mantle is then brought back and the flask is heated to 265°C.
  • Figure 3 shows the temperature profile for the reaction (recorded directly from the controller).
  • the InP cores had an exciton with a CWL of 579 nm and max/min exciton peak optical density ratio of 1.49
  • the final solution is cleaned with a mixture of anhydrous toluene and ethanol (ratio
  • inventive material combinations are used in the following layer sequence:
  • EML emission layer
  • ETL electron-transport layer
  • EIL electron injection layer
  • the hole-transport layer is the polymer of the structure shown in table 7, which is synthesised according to WO2010/097155.
  • the polymer is dis- solved in toluene, so that the solution typically has a solid content of approx. 5 g/l if, as here, the layer thickness of 20 nm which is typical for a device is to be achieved by means of spin coating.
  • the layers are applied by spin coating in an inert-gas atmosphere, in the present case argon, and dried by heating at 220°C for 30 min.
  • the emission layer is composed of one of the materials according to the present invention for each single ELQ-LED device.
  • the materials used in this example E1 to E5 are disclosed in table 8.
  • the emissive layer material is dissolved in toluene.
  • the solids content of such solutions is about 30 mg/ml if, as here, the layer thickness of 30nm which is typical for a device is to be achieved by means of spin coating.
  • the layers are applied by spin coating in an inert-gas atmosphere, and dried by heating at 120°C for 10 minutes.
  • Table 7 shows the structural formulae of the materials used for the ELQ- LEDs devices
  • the materials for the electron-transport layer and the electron injection layer are likewise applied by thermal vapour deposition in a vacuum chamber and are shown as well in table 7.
  • the electron-transport layer consists of the material ETM and the electron injection layer consists of LiQ.
  • the cathode is formed by the thermal evaporation of an aluminium layer with a thickness of 100 nm.
  • the ELQ-LEDs are characterised by standard methods. For this purpose, the current/voltage/luminance characteristic lines (IUL characteristic lines) and the electroluminescence (EL) spectra are recorded. The EL spectra are taken at a luminous density of 10cd/m 2 and the CIE 1931 x and y coordinates are then calculated from the EL spectrum.
  • the device data of various ELQ-LEDs is summarized in Table 8 and Fig. 4 shows the EL spectrum of the ELQ-LED devices fabricated in this working example.
  • the reaction contents are centrifuged at 2700G for 7 minutes to isolate the supernatant (SN).
  • Acetonitrile (ACN, 80 ml_) is then added to the SN, which is centrifuged to isolate the percipirate (PPT).
  • the PPT is then subject to several rounds of solvent/antisolvent centrifuge precipitation using toluene and ACN. Finally, the PPT is dispersed in squalane to a concentration of 1.39 x10 6 mol MSC/mL squalane.
  • Distilled squalane (60 ml_) is vacuumed for 1 hour at 200 mTorr in a 250 ml_ four necked round bottom flask. Then, under Argon gas, the flask is heated to 375 °C. Squalane (1.12 ml_) is added to part of the MSC solution described above (10.9 ml_), and 10 ml_ of the new solution is injected into the flask. After 1 min the reaction flask is cooled to 200 °C.
  • InP QDs (2.7 x10 7 mol), prepared according to InP Core Synthesis described above, are dispersed in oleylamine (3.7 ml_) and transferred into a 50 mL four necked round bottom flask inside a Nitrogen glove box. ZnCh (0.065 g) is added to the flask. The flask is vacuumed on the Schlenk line below 150 mTorr at 35 °C for 30 min. Then, under Argon, the flask is heated at 250 °C for 3 min. The flask is cooled to 180 °C.
  • ZnCh in oleylamine (2 mL, 0.55M, pre-complexed by vacuuming for 1 hour at 120 °C) and TOP:Se (0.55 mL, 2M) are injected into the flask. 30 minutes after the injection, the temperature is raised to 200 °C and maintained for 30 minutes. Then the temperature is raised to 320 °C, and Zinc stearate in oleylamine (2.4 mL, 0.4 M, pre-complexed by vacuuming for 1 hour at 100 °C) is injected dropwise over 10 min into the flask. After 3 hours at 320 °C, the flask is cooled to room temperature.
  • Synthesis is carried out as in Reference Example 1 , except for the following differences: 1 ) 0.425 ml_ of TOP:Se (2M) are used. 2) 10 minutes after the injection of zinc stearate in oleylamine, TOP:S (0.125 ml_, 2.24 M) is injected into the flask. The reaction is held at 320 °C for 3 hours before cooling to room temperature. Crude QY measurement, surface treatment, and post surface treatment QY measurement are carried out as in
  • Synthesis is carried out as in Reference Example 1 , except for the following differences: 1 ) 0.275 ml_ of TOP:Se (2M) are used. 2) 10 minutes after the injection of zinc stearate in oleylamine, TOP:S (0.25 ml_, 2.24 M) is injected into the flask. The reaction is held at 320 °C for 3 hours before cooling to room temperature. Crude QY measurement, surface treatment, and post surface treatment QY measurement are carried out as in Comparative Example 1.
  • InP QDs (3.5 x10 7 mol), prepared according to InP Core Synthesis described above, are dispersed in oleylamine (4.8 ml_) and transferred into a 50 mL four necked round bottom flask inside a Nitrogen glove box. ZnCh (0.085 g) is added to the flask. The flask is vacuumed on the Schlenk line below 150 mTorr at 35 °C for 30 min. Then, under Argon, the flask is heated at 250 °C for 3 min. The flask is cooled to 180 °C.
  • ZnCh in oleylamine (2.6 mL, 0.55M, pre-complexed by vacuuming for 1 hour at 120 °C) and TOP:Se (0.48 mL, 2M) are injected into the flask. 30 minutes after the injection, the temperature is raised to 200 °C and maintained for 30 minutes. Then the temperature is raised to 320 °C, and Zinc stearate in oleylamine (2.4 mL, 0.4 M, pre-complexed by vacuuming for 1 hour at 100 °C) is injected dropwise over 10 min into the flask.
  • Table 9 shows that in the Working examples, which have a Se/S ratio range of 1 -2, QY of over 75% is achieved while SA remains below 0.315 after surface treatment with Zn-acetate and illumination. These examples show a percent increase of QY of over 40%, giving final QY values of > 75% after surface treatment. In contrast, the Comparative examples which have Se:S ratios below 1 or above 2 show lower percent increases of QY after surface treatment with Zn-acetate and illumination.
  • Se:S ratio range of 1 -2 in conjunction with surface treatment as an optimal range which a) significantly increases the QY by S incorporation, b) does not overdo S incorporation, which would increase the lattice strain and lower QY, and c) maintains a low SA (compare to SA of 0.353 in Comparative example 5 in the case of S only).
  • the product is cleaned from the organic ligands in toluene/ethanol mixtures. Cleaned product is dissolved in analytical toluene and a concentrated solution is dripped on a Si chip.
  • a concentrated solution is dripped on a Si chip.
  • the solution is diluted and one droplet of the diluted solution is dripped on a Cu/C TEM grid with ultrathin amorphous carbon layer.
  • the Si chip/grid is dried in vacuum of ⁇ 8x10-2 torr at 90oC for 1 5hrs to remove the residues of the solvent as well as possible organic residues.
  • SEM EDS is carried out on FEI sirion machine equipped with Oxford detector and INCA software. Accelerating voltage of 25kV is used.

Abstract

The present invention relates to a semiconducting nanoparticle.

Description

Semiconducting nanoparticle
Field of the invention
The present invention relates to a semiconducting light emitting
nanoparticle; a process for preparing a semiconducting light emitting nanoparticle; composition, formulation and use of a semiconducting light emitting nanoparticle, an optical medium; and an optical device.
Background Art
Semiconducting light emitting nanoparticles are known in the prior art documents.
Recently a method for synthesizing InP quantum dots using InP magic sized clusters (MSCs) as single source precursors (SSP) instead of the PTMS and indium-carboxylate is reported by D. Gary et al., Chem. Mater., 2015, 1432.
Due to this most syntheses of InP core/shell dots give an FWHM for the final photoluminescence peak of >40nm. One paper by X. Yang et al., Adv. Mater., 2012, 24, 4180 gives an FWFIM of 38nm. In these syntheses the
FWFIM of the final core/shell is largely determined by the size distribution of the InP cores and this ultimately limits the FWFIM breadth.
Lim et. al. ACS Nano. VOL. 7, NO. 10, 9019-9026, 2013 discloses
InP/ZnSeS QDs fabricated with using 0.4 mmol of STBP (0.4 mmol of sulfur dissolved in 0.5 mL of TBP and 0.5 mL of ODE) and 0.2 mL of SeTOP (0.2 mmol of Se dissolved in 0.5 mL of n-trioctylphosphine and 0.5 mL of ODE) and InP quantum dot (QD)-based light-emitting diodes (QLEDs). Patent Literature
No literature Non- Patent Literature
1. D. Gary et al., Chem. Mater., 2015, 1432
2. X. Yang et al., Adv. Mater., 2012, 24, 4180
3. Lim et. al. ACS Nano. VOL. 7, NO. 10, 9019-9026, 2013
Summary of the invention
However, the inventors newly have found that there is still one or more of considerable problems for which improvement is desired, as listed below; improvement of particle size distribution, better Full Width at Half Maximum (FWHM) value, improved self-absorption value, improvement of quantum yield of nanoparticle, lowering trap emission of nanoparticle, optimizing the interface between core and shell layers, optimizing a surface condition of core part of nanoparticle, reducing lattice defects of cores and/or shell layers of nanoparticle, realizing a better light emission of nanoparticle with our without shell layers, optimizing fabrication process of nanoparticle, providing new fabrication process to improve size control of nanoparticle, environmentally more friendly and safer fabrication process.
The inventors aimed to solve one or more of the above-mentioned problems.
Then it is found a novel semiconducting light emitting nanoparticle comprising at least a first semiconducting material comprising at least a 1st element of group 13 elements of the periodic table and a 2nd element of the group 15 elements of the periodic table, and at least one shell layer comprising at least a 3rd element of the group 12 elements of the periodic table and a 4th element of the group 16 elements of the periodic table, wherein the nanoparticle has the self-absorption value 0.35 or less, preferably it is in the range from 0.30 to 0.01 , more preferably from 0.25 to 0.05, even more preferably from 0.23 to 0.12, and the Full Width at Half Maximum 46 nm or less, preferably it is in the range from 46 nm to 20 nm, more preferably from 40 nm to 25 nm, even more preferably from 38 nm to 30 nm.
In another aspect, the present invention relates to a semiconducting light emitting nanoparticle comprising at least a first semiconducting material comprising at least a 1 st element of group 13 elements of the periodic table and a 2nd element of the group 15 elements of the periodic table, and at least one shell layer comprising at least a 3rd element of the group 12 elements of the periodic table and a 4th element of the group 16 elements of the periodic table, wherein the size distribution of the first semiconducting material is 10% or less, preferably in the range from 10% to 3%, more preferably from 8% to 4%, and the volume ratio between the shell layer and the first semiconducting material is 5 or more, preferably it is in the range from 5 to 40, more preferably it is from 10 to 30.
In another aspect, the present invention relates to a semiconducting light emitting nanoparticle comprising at least a first semiconducting material comprising at least a 1 st element of group 13 elements of the periodic table and a 2nd element of the group 15 elements of the periodic table, and at least one shell layer wherein the shell layer is represented by following formula (II),
MSei-zSz (II) wherein M is Zn2+, or Cd2+, preferably M is Zn2+; 0<z<1 , and the ratio of Se and S elements in the shell layer is in the range from 0.6 to 4.0, preferably it is in the range from 0.7 to 3.0, more preferably it is in the range from 0.8 to 2.5, even more preferably from 1.0 to 2.0. In another aspect, the present invention relates to a new process for synthesizing a semiconducting material comprising following steps (a) to
(h),
(a) mixing a semiconductor nanosized cluster and an another compound or to an another mixture of compounds at a temperature in the range from 260 to 500°C in order to get a reaction mixture, preferably said temperature is in the range from 300 to 460°C, more preferably from 330 to 430°C, even more preferably from 360 to 400°C, (b) cooling the reaction mixture to slow down or stop the growth of a first semiconducting material in step (a),
(c) adjusting or keeping the temperature of the reaction mixture from step
(b) in the range from 40 °C to 300 °C, preferably in the range from 50 °C to 290 °C, more preferably from 60 °C to 280 °C, furthermore preferably from
65 °C to 270°C to allow a growth of a first semiconducting material in the mixture,
(d) adding a semiconductor nanosized cluster to the reaction mixture,
(e) adjusting or keeping the temperature of the reaction mixture from step (d) in the range from 40 °C to 300 °C, preferably in the range from 50 °C to 290 °C, more preferably it is from 60 °C to 280 °C, furthermore preferably from 65 °C to 270°C to allow a growth of a first semiconducting material in the mixture, (f) optionally repeating steps (d) and (e),
(g) adjusting or keeping the temperature of the reaction mixture from step (e) or (f) in the range from 200 °C to 350 °C, preferably in the range from 230 °C to 320 °C, more preferably it is from 240°C to 310 °C, furthermore preferably from 250°C to 300°C to allow growth of a first semiconducting material in the mixture,
(h) cooling the reaction mixture to stop the growth of first semiconducting material in step (e) or step (f).
In another aspect, the present invention relates to a new process for synthesizing a semiconducting light emitting nanoparticle comprising following steps (i) and (j), (i) mixing a first semiconducting material, preferably it is obtained in the step (h), and at least a first cation shell precursor and a first anion shell precursor, optionally in a solvent, to form a shell layer onto the first semiconducting material, (j) quenching a shell formation of step (d), wherein said first cation shell precursor is a salt of an element of the group 12 of the periodic table and the first anion shell precursor is a source of an element of the group 16 of the periodic table, more preferably said first cation shell precursor is selected from one or more member s of the group consisting of Zn-stearate, Zn-myristate, Zn-oleate, Zn-laurate, Zn-palmitate, Zn-acetylacetonate, Cd-stearate, Cd-myristate, Cd-oleate, Cd-laurate, Cd- palmitate, Cd-acetylacetonate a metal halogen represented by chemical formula (III) and a metal carboxylate represented by chemical formula (IV),
MX2n (III) wherein M is Zn2+, or Cd2+, preferably M is Zn2+, X2 is a halogen selected from the group consisting of Cl , Br and I , n is 2,
[M(02CR1) (02CR2)] - (IV) wherein M is Zn2+, or Cd2+, preferably M is Zn2+;
R1 is a linear alkyl group having 1 to 30 carbon atoms, a branched alkyl group having 4 to 30 carbon atoms, a linear alkenyl group having 2 to 30 carbon atoms, or a branched alkenyl group having 4 to 30 carbon atoms, preferably R1 is a linear alkyl group having 1 to 30 carbon atoms, or a linear alkenyl group having 2 to 30 carbon atoms, more preferably, R1 is a linear alkyl group having 5 to 25 carbon atoms, or a linear alkenyl group having 6 to 25 carbon atoms, even more preferably R1 is a linear alkyl group having 10 to 20 carbon atoms, or a linear alkenyl group having 10 to 20 carbon atoms, furthermore preferably R1 is a linear alkenyl group having 10 to 20 carbon atoms,
R2 is a linear alkyl group having 1 to 30 carbon atoms, a branched alkyl group having 4 to 30 carbon atoms, a linear alkenyl group having 2 to 30 carbon atoms, or a branched alkenyl group having 4 to 30 carbon atoms, preferably R2 is a linear alkyl group having 1 to 30 carbon atoms, or a linear alkenyl group having 2 to 30 carbon atoms, more preferably R2 is a linear alkyl group having 5 to 25 carbon atoms, or a linear alkenyl group having 6 to 25 carbon atoms, even more preferably R2 is a linear alkyl group having 10 to 20 carbon atoms, or a linear alkenyl group having 10 to 20 carbon atoms, furthermore preferably R2 is a linear alkenyl group having 10 to 20 carbon atoms, and preferably said anion shell precursor is selected from one or more members of the group consisting of Trioctylphosphine : Se,
Tributylphosphine : Se, Trioctylphosphine : S, Tributylphosphine : S, and thiols.
In another aspect, the present invention further relates to a semiconducting material obtainable or obtained from the process.
In another aspect, the present invention further relates to a semiconducting light emitting nanoparticle obtainable or obtained from the process. In another aspect, the present invention also relates to composition comprising at least one semiconducting light emitting nanoparticle of the present invention, or at least one semiconducting material of the present invention, and at least one additional material, preferably the additional material is selected from the group consisting of organic light emitting materials, inorganic light emitting materials, charge transporting materials, scattering particles, and matrix materials, preferably the matrix materials are optically transparent polymers.
In another aspect, the present invention relates to formulation comprising at least one semiconducting light emitting nanoparticle, or at least one semiconducting material or the composition, and at least one solvent, preferably the solvent is selected from one or more members of the group consisting of aromatic, halogenated and aliphatic hydrocarbon solvents, more preferably selected from one or more members of the group consisting of toluene, xylene, ethers, tetrahydrofuran, chloroform, dichloromethane and heptane, purified water, ester acetates, alcohols, sulfoxides, formamides, nitrides, ketones.
In another aspect, the present invention relates to use of the
semiconducting light emitting nanoparticle, or the semiconducting material, or the composition, or the formulation in an electronic device, optical device or in a biomedical device.
In another aspect, the present invention further relates to an optical medium comprising at least one semiconducting light emitting nanoparticle, or the composition.
In another aspect, the present invention further relates to an optical device comprising at least said optical medium.
Description of drawings
Figure 1 shows the results of shell coating of working example 8.
Figure 2 shows the results of shell coating of working example 9.
Figure 3 shows the temperature profile for the reaction (recorded directly from the controller) of working example 12.
Figure 4 shows the EL spectrum of the ELQ-LED devices fabricated in the working example 13.
Detailed description of the invention
- Semiconducting light emitting nanoparticle
According to the present invention, in one aspect, said semiconducting light emitting nanoparticle comprises at least a first semiconducting material comprising at least a 1st element of group 13 elements of the periodic table and a 2nd element of the group 15 elements of the periodic table, and at least one shell layer comprising at least a 3rd element of the group 12 elements of the periodic table and a 4th element of the group 16 elements of the periodic table, wherein the nanoparticle has the self-absorption value 0.35 or less, preferably it is in the range from 0.30 to 0.01 , more preferably from 0.25 to 0.05, even more preferably from 0.23 to 0.12, and the Full Width at Half Maximum (FWHM) 46 nm or less, preferably it is in the range from 46 nm to 20 nm, more preferably from 40 nm to 25 nm, even more preferably from 38 nm to 30 nm.
In a preferred embodiment of the present invention, the nanoparticle has the trap emission 15 % or less, preferably 10% or less, more preferably it is in the range from 8% to 5%.
According to the present invention, the Self-absorption value is calculated preferably according to the following procedure:
According to the present invention, the optical density (hereafter“OD”) of the nanoparticles is preferably measured using Shimadzu UV-1800, double beam spectrophotometer, using toluene baseline, in the range between 350 and 800 nm.
The photoluminescence spectra (hereafter“PL”) of the nanoparticles is preferably measured using Jasco FP fluorimeter, in the range between 460 and 800 nm, using 450 nm excitation.
The OD(A) and PL (A) are the measured optical density and the photoluminescence at wavelength of A. OD1 represented by the formula (X) is the optical density normalized to the optical density at 450 nm, and ai represented by formula (XI) is the absorption corresponding to the normalized optical density.
Figure imgf000011_0001
Preferably, the determination of the full width half maximum (FWHM) is made with an appropriate data base preferably comprising at least 10, more preferably at least 20 and even more preferably at least 50 data points. The determination is preferably performed by using LabVIEW Software
(LabVIEW 2017; May 2017) with the following Vis (Virtual Instrument):
1. 'Peak detector' for finding center wavelength and y-value (counts).
The following parameters are preferably used: width: 10, threshold: maximum value of input data divided by 5.
2. Dividing the counts (y-value) at the center wavelength value (see item 1 ) by 2 giving the y-value for the half-width of the peak. The two points having this half-width y-value were found and the difference between their two wavelength values were taken to give the FWHM parameter.
The self-absorption value of the nanoparticles represented by formula (XII) is preferably calculated based on the OD and PL measurement raw data.
It is believed that lower-self absorbance of the nanoparticles is expected to prevent the QY decrease in high emitter concentrations. Preferably, the nanoparticle emits light having the peak maximum light emission wavelength in the range from 520nm to 700nm, preferably from 550nm to 650nm, more preferably from 580nm to 650nm. In a preferred embodiment of the present invention, the average diameter of the first semiconducting material is in the range from 1 to 4 nm, preferably it is in the range from 2.5 to 4.0, more preferably from 2.7 to 3.6.
The average diameter of the semiconducting nanosized light emitting particles are calculated based on 100 semiconducting light emitting nanoparticles in a TEM image created by a Tecnai G2 Spirit Twin T-12 Transmission Electron Microscope.
According to the present invention, in a preferred embodiment, the size distribution of the first semiconducting material is 10% or less, preferably it is in the range from 10% to 3%, more preferably from 8% to 4%.
Preferably, the volume ratio between the shell layer and the first
semiconducting material as a core is 5 or more, preferably it is in the range from 5 to 40, more preferably it is from 10 to 30.
According to the present invention, said shell / core ratio (the ratio of shell / the first semiconducting material as a core) is calculated using following formula (XIII).
Mw(Total shell elements)
Vs hell The element of the group 12 piTotal shell elements )
) · Mw(Total core elements ) (XIII) Vcore The element of the group 13
piTotal core elements ) wherein the symbols have the following meaning
Vshell = the volume of shell layer(s), Vcore = the volume of core,
Mw (Total shell elements) = molecular weight of total shell elements,
Mw (Total core elements) = molecular weight of total core elements p (Total shell elements) = density of total shell elements
p (Total core elements) = density of total core elements
- Elemental Analysis
According to the present invention, the following elemental analysis is used in order to determine the molar ratio between group 12 element and group 13 element.
The semiconducting light emitting nanoparticle is dissolved in toluene and the obtained solution is diluted. One droplet of the diluted solution is dripped on a Cu/C TEM grid with ultrathin amorphous carbon layer. The grid is dried in vacuum at 80°C for 1.5 hours to remove the residues of the solvent as well as possible organic residues.
EDS measurements are carried out in STEM mode using high resolution TEM - Tecnai F20 G2 machine operating at 200kV equipped with EDAX Energy Dispersive X-Ray Spectrometer. TIA software is used for spectra acquisition and calculations and no standards are used.
The atomic ratio of the element of the group 12 and the element of the group 13 of the periodic table is used for the shell / core ratio calculation.
For examples, in case the semiconducting light emitting nanoparticle is InP/ZnSe, the calculation is carried out as follows.
Figure imgf000013_0001
According to the present invention, the term“semiconductor” means a material that has electrical conductivity to a degree between that of a conductor (such as copper) and that of an insulator (such as glass) at room temperature. Preferably, a semiconductor is a material whose electrical conductivity increases with the temperature. The term“nanosized” means the size in between 0.1 nm and 999 nm, preferably 1 nm to 150 nm, more preferbaly 3nm to 50 nm.
Thus, according to the present invention,“semiconducting light emitting nanoparticle” is taken to mean that the light emitting material which size is in between 0.1 nm and 999 nm, preferably 1 nm to 150 nm, more preferbaly 3nm to 50nm, having electrical conductivity to a degree between that of a conductor (such as copper) and that of an insulator (such as glass) at room temperature, preferably, a semiconductor is a material whose electrical conductivity increases with the temperature, and the size is in between 0.1 nm and 999 nm, preferably 0,5 nm to 150 nm, more preferbaly 1 nm to 50 nm.
According to the present invention, the term“size” means the average diameter of the longest axis of the semiconducting nanosized light emitting particles.
In a preferred embodiment of the present invention, the semiconducting light emitting nanoparticle of the present invention is a quantum sized material.
According to the present invention, the term“quantum sized” means the size of the semiconducting material itself without ligands or another surface modification, which can show the quantum confinement effect, like described in, for example, ISBN:978-3-662-44822-9.
Generally, it is said that the quantum sized materials can emit tunable, sharp and vivid colored light due to“quantum confinement” effect. In some embodiments of the invention, the size of the overall structures of the quantum sized material, is from 1 nm to 50 nm, more preferably, it is from 1 nm to 30 nm, even more preferably, it is from 5 nm to 15 nm.
According to the present invention, said first semiconducting nanosized material can be varied.
In another aspect of the present invention, a semiconducting light emitting nanoparticle comprises at least a first semiconducting material comprising at least a 1st element of group 13 elements of the periodic table and a 2nd element of the group 15 elements of the periodic table, and at least one shell layer comprising at least a 3rd element of the group 12 elements of the periodic table and a 4th element of the group 16 elements of the periodic table, wherein the size distribution of the first semiconducting material is 10% or less, preferably in the range from 10% to 3%, more preferably from 8% to 4%, and the volume ratio between the shell layer and the first semiconducting material is 5 or more, preferably it is in the range from 5 to 40, more preferably it is from 10 to 30. In some embodiments of the present invention, the shell layer is
represented by following formula (II),
MSei-zSz (II) wherein M is Zn2+, or Cd2+, preferably M is Zn2+; 0£z<1 , preferably 0<z<1. In a preferred embodiment of the present invention, the ratio of Se and S elements in the shell layer is in the range from 0.6 to 4.0, preferably it is in the range from 0.7 to 3.0, more preferably it is in the range from 0.8 to 2.5, even more preferably from 1.0 to 2.0.
In another aspect of the present invention, a semiconducting light emitting nanoparticle comprises at least a first semiconducting material comprising at least a 1st element of group 13 elements of the periodic table and a 2nd element of the group 15 elements of the periodic table, and at least one shell layer, wherein the shell layer is represented by following formula (II), MSei-zSz (II) wherein M is Zn2+, or Cd2+, preferably M is Zn2+; 0<z<1 , and the ratio of Se and S elements in the shell layer is in the range from 0.6 to 4.0, preferably it is in the range from 0.7 to 3.0, more preferably it is in the range from 0.8 to 2.5, even more preferably from 1.0 to 2.0.
In some embodiments of the present invention, the concentration of Se in the shell layer varies from a high concentration of the first semiconducting material side in the shell layer to a low concentration of the opposite side in the shell layer, more preferably, the concentration of S in the shell layer varies from a low concentration of first semiconducting material side of the shell layer to a higher concentration to the opposite side of the shell layer.
According to the present invention, in some embodiments, the
semiconducting light emitting nanoparticle further comprises a 2nd shell layer onto said shell layer. - First semiconducting material
In a preferred embodiment of the present invention, wherein the first semiconducting material is represented by following chemical formula (I), ln(i-x-y-z-q)Ga1 .SxZnySzSeqP (I) wherein 0<x<1 , 0<y<1 , 0<z<1 , 0<q<1 , 0<x+y+z+q <1.
In a preferred embodiment of the present invention, the first semiconducting material has the value of the ratio of the exciton absorption peak and exciton absorption minimum of said first semiconducting material 1.6 or more at exciton wavelength 570 nm or more, preferably 1.6 or more at exciton wavelength in the range from 570 nm to 600 nm, preferably in the range 1.6 to 1.7 at exciton wavelength in the range from 565 nm to 600 nm, even more preferably in the range 1.6 to 1.7 at exciton wavelength in the range from 570nm to 580 nm.
In some embodiments of the present invention, the nanoparticle further comprises a zinc containing organic material selected from the group consisting of zinc carboxylates, zinc phosphonates, zinc xanthates, zinc dithiocarbamates, preferably the first semiconducting material, the shell layer and the zinc containing organic material is placed in this sequence.
According to the present invention, a type of shape of the first
semiconducting nanosized material of the semiconducting light emitting nanoparticle, and shape of the semiconducting light emitting nanoparticle to be synthesized are not particularly limited.
For examples, spherical shaped, elongated shaped, star shaped, polyhedron shaped, pyramidal shaped, tetrapod shaped, tetrahedron shaped, platelet shaped, cone shaped, and irregular shaped first semiconducting nanosized material and - or a semiconducting light emitting nanoparticle can be synthesized.
In some embodiments of the present invention, the average diameter of the first semiconducting nanosized material is in the range from 1.5 nm to 3.5 nm.
-Semiconducting light emitting nanoparticle
In some embodiments of the present invention, said semiconducting light emitting nanoparticle has a quantum yield 10% or more, preferably in the range from 10% to 90% more preferably from 20% to 80%, even more preferably from 50% to 78%, furthermore preferably from 60% to 78%.
In some embodiments of the present invention, the nanoparticle preferably has a relative quantum yield of at most 90 %, more preferably at most 80 %, even more preferably at most 78 % measured by calculating the ratio of the emission counts of the nanoparticle and the dye coumarin 153 (CAS 53518-18-6) and multiplying by the QY of the dye (54.4%) measured at 25°C.
In specific embodiments of the present invention, the nanoparticle preferably has a relative quantum yield in the range of 10 % to 90 %, more preferably in the range of 20 to 80 %, even more preferably in the range of 50 to 80 %, and even more preferably in the range of 60 to 78 % measured by calculating the ratio of the emission counts of the QD and the dye coumarin 153 (CAS 53518-18-6) and multiplying by the QY of the dye (54.4%) measured at 25°C.
In a preferred embodiment of the present invention, the nanoparticle has a relative quantum yield in the range of 10 % to 90 % without any shell layer, more preferably in the range of 20 to 80 %, even more preferably in the range of 50 to 80 %, and even more preferably in the range of 60 to 78 % measured by calculating the ratio of the emission counts of the QD and the dye coumarin 153 (CAS 53518-18-6) and multiplying by the QY of the dye (54.4%) measured at 25°C.
The relative quantum yield is preferably calculated using absorbance and emission spectrum (excited at 350 nm), obtained using Shimadzu UV-1800 and Jasco FP-8300 spectrophotometer, using the following formula, with coumarin 153 dye in ethanol is used as a reference, with a quantum yield of 55%.
Figure imgf000019_0001
wherein the symbols have the following meaning
QY = Quantum Yield of the sample
QYref = Quantum Yield of the reference/standard
n = the refractive index of the sample solvent (especially ethanol) nref = the refractive index of the reference/standard
I = the integral of the sample emission intensity as measured on the
Jasco. Calculated as Jl dv with I intensity, v =wavelength.
A = is the percentage absorbance of the sample. The percentage of the sampling light that the sample absorbs.
I ref = the integral of the reference emission intensity as measured on the Jasco. Calculated as Jl dv with I intensity, v =wavelength. Aref is the percentage absorbance of the reference. The percentage of the sampling light that the reference absorbs.
The absorbance and emission spectrum is achieved at a temperature of about 25°C. In some embodiments of the present invention, the trap emission value of the nanoparticle is in the range from 0.02 to 0.15, preferably 0.05 to 0.1.
According to the present invention, the trap emission value is calculated using following formula,
The photoluminescence spectra (hereafter "PL”) of the nanoparticles is measured using Jasco FP fluorimeter, in the range between 460 and 800 nm, using 450 nm excitation.
Figure imgf000020_0001
wherein the symbols have the following meanings;
CWL=the peak maximum light emission wavelength of the
photoluminescence spectra,
FWHM=full width at half maximum of the photoluminescence spectra, RI_(l)= photoluminescence intensity at wavelength of l. According to the present invention, in some embodiments, the first semiconducting material as a core is at least partially embedded in the second semiconducting material, preferably said first semiconducting material is fully embedded into the second semiconducting material. In some embodiments of the present invention, said shell layer comprises at least a 1st element of group 12 of the periodic table and a 2nd element of group 16 of the periodic table, preferably, the 1st element is Zn, and the 2nd element is S, Se, or Te. In a preferred embodiment of the present invention, the second
semiconducting material as the shell layer is represented by following formula (V), ZnSxSeyTez, - (V) wherein 0£x<1 , 0£y<1 , 0£z<1 , and x+y+z=1 , preferably, the shell layer is ZnSe, ZnSxSey, ZnSeyT ez or ZnSxT ez.
In some embodiments of the present invention, said shell layer is an alloyed shell layer or a graded shell layer preferably said graded shell layer is ZnSxSey, ZnSeyTez, or ZnSxTez, more preferably it is ZnSxSey.
The ratio of y /x is preferably larger than 0.6, more preferably in the range from 0.6 to 10, even more preferably in the range from 0.7 to 5, furthermore preferably from 1 to 3, the most preferably in the range from 1 to 2. The ratio of y/z is preferably larger than 1 and more preferably larger than 2, and even more preferably larger than 4.
In some embodiments of the present invention, the semiconducting light emitting nanoparticle further comprises a 2nd shell layer onto said shell layer, preferably the 2nd shell layer comprises or a consisting of a 3rd element of group 12 of the periodic table and a 4th element of group 16 of the periodic table, more preferably the 3rd element is Zn, and the 4th element is S, Se, or Te with the proviso that the 4th element and the 2nd element are not the same.
In a preferred embodiment of the present invention, the 2nd shell layer is represented by following formula (V'),
ZnSxSeyTez, - (V') wherein the formula (V'), 0£x<1 , 0£y<1 , 0£z<1 , and x+y+z=1 , preferably, the shell layer is ZnSe, ZnSxSey, ZnSeyTez, or ZnSxTezwith the proviso that the shell layer and the 2nd shell layer is not the same. In some embodiments of the present invention, said 2nd shell layer can be an alloyed shell layer or a graded shell layer, preferably said graded shell layer is ZnSxSey, ZnSeyTez, or ZnSxTez, more preferably it is ZnSxSey.
In some embodiments of the present invention, the semiconducting light emitting nanoparticle can further comprise one or more additional shell layers onto the 2nd shell layer as a multishell.
According to the present invention, the term "multishells" stands for the stacked shell layers consisting of three or more shell layers.
In some embodiments of the present invention, the surface of the
semiconducting light emitting nanoparticle can be over coated with one or more kinds of surface ligands. Without wishing to be bound by theory it is believed that such surface ligands may lead to disperse the nanosized fluorescent material in a solvent more easily.
The surface ligands in common use include phosphines and phosphine oxides such as Trioctylphosphine oxide (TOPO), Trioctylphosphine (TOP), and Tributylphosphine (TBP); phosphonic acids such as
Dodecylphosphonic acid (DDPA), Tridecylphosphonic acid (TDPA), amines such as Oleylamine, Dedecyl amine (DDA), Tetradecyl amine (TDA), Hexadecyl amine (HDA), and Octadecyl amine (ODA), Oleylamine (OLA), 1 -Octadecene (ODE), thiols such as hexadecane thiol and hexane thiol; mercapto carboxylic acids such as mercapto propionic acid and
mercaptoundecanoicacid; carboxylic acids such as oleic acid, stearic acid, myristic acid; acetic acid and a combination of any of these. Furthermore, the ligands can include Zn-oleate, Zn-acetate, Zn-myristate, Zn-Stearate, Zn-laurate and other Zn-carboxylates. And. Polyethylenimine (PEI) also can be used preferably.
Examples of surface ligands have been described in, for example, the laid- open international patent application No. WO 2012/059931 A.
- Process
- Process for synthesizing a semiconducting material
In another aspect, the present invention also relates to a process for synthesizing a semiconducting material comprising at least following steps
(a) to (h), (a) mixing a semiconductor nanosized cluster and an another compound or to an another mixture of compounds at a temperature in the range from 260 to 500°C in order to get a reaction mixture, preferably said temperature is in the range from 300 to 460°C, more preferably from 330 to 430°C, even more preferably from 360 to 400°C,
(b) cooling the reaction mixture to slow down or stop the growth of a first semiconducting material in step (a),
(c) adjusting or keeping the temperature of the reaction mixture from step (b) in the range from 40 °C to 300 °C, preferably in the range from 50 °C to
290 °C, more preferably from 60 °C to 280 °C, furthermore preferably from 65 °C to 270°C to allow a growth of a first semiconducting material in the mixture, (d) adding a semiconductor nanosized cluster to the reaction mixture, (e) adjusting or keeping the temperature of the reaction mixture from step (d) in the range from 40 °C to 300 °C, preferably in the range from 50 °C to 290 °C, more preferably it is from 60 °C to 280 °C, furthermore preferably from 65 °C to 270°C to allow a growth of a first semiconducting material in the mixture,
(f) optionally repeating steps (d) and (e),
(g) adjusting or keeping the temperature of the reaction mixture from step (e) or (f) in the range from 200 °C to 350 °C, preferably in the range from
230 °C to 320 °C, more preferably it is from 240°C to 310 °C, furthermore preferably from 250°C to 300°C to allow growth of a first semiconducting material in the mixture, (h) cooling the reaction mixture to stop the growth of first semiconducting material in step (e) or step (f).
In a preferred embodiment of the present invention, the process comprises steps (a), (b), (c), (d), (e), (f), (g), (h) in this sequence.
In some embodiments of the present invention, optionally, a cation precursor and/or an anion precursor are added in step (a) and/or step (b1 ), wherein a cation precursor is selected from one or more members of the group consisting of a Ga precursor selected from one or more members of the group consisting of GaC , GaBr3, Gab, Ga-stearate, Ga-myristate, Ga- oleate, Ga-laurate, Ga-palmitate, Ga-carboxylates, and Ga- acetylacetonate, a Zn precursor selected from one or more members of the group consisting of ZnC , ZnBr2, Zn , Zn-stearate, Zn-myristate, Zn-oleate, Zn-laurate, Zn-palmitate, Zn-carboxylates, and Zn-acetylacetonate; and an anion precursor is selected from one or more member of the group consisting of Trioctylphosphine : Se, Tributylphosphine : Se, Trioctylphosphine :S, Tributylphosphine :S, and thiols, at the same time or each separately.
In a preferred embodiment of the present invention, said another compound is a solvent.
In a preferred embodiment of the present invention, said another compound is a solvent having the boiling point 250 °C or more, preferably in the range from 250 °C to 500 °C, more preferably in the range from 300 °C to 480 °C, even more preferably from 350 °C to 450 °C, furthermore preferably it is from 370°C to 430 °C.
In a preferred embodiment of the present invention, said another compound is a solvent selected from one or more members of the group consisting of squalenes, squalanes, heptadecanes, octadecanes, octadecenes, nonadecanes, icosanes, henicosanes, docosanes, tricosanes,
pentacosanes, hexacosanes, octacosanes, nonacosanes, triacontanes, hentriacontanes, dotriacontanes, tritriacontanes, tetratriacontanes, pentatriacontanes, hexatriacontanes, oleylamines, and trioctylamines, with preferably being of squalene, squalane, heptadecane, octadecane, octadecene, nonadecane, icosane, henicosane, docosane, tricosane, pentacosane, hexacosane, octacosane, nonacosane, triacontane, hentriacontane, dotriacontane, tritriacontane, tetratriacontane,
pentatriacontane, hexatriacontane, oleylamine, and trioctylamine, more preferably squalane, pentacosane, hexacosane, octacosane, nonacosane, or triacontane, even more preferably squalane, pentacosane, or
hexacosane.
In some embodiments of the present invention, the temperature of the reaction mixture in step (a) is kept in the temperature range for from 1 second to 10 minutes, preferably from 5 seconds to 5 minutes, more preferably from 10 seconds to 200 seconds, more preferably from 20 seconds to 160 seconds.
In some embodiments of the present invention, the total amount of the inorganic part of said lll-V semiconductor nanosized clusters in step (a) is in the range from 0.1x1 O 4 to 1x1 O 3 mol%, preferably being of the amount in the range from 0.5x1 O 4 to 5x1 O 4 mol%, more preferably from 1x1 O 4 to 3x104 mol% of the reaction mixture. Step (b)
In a preferred embodiment of the present invention, the cooling rate in step (b) is in the range from 0.05°C/s to 50°C/s, preferably it is from 0.1 °C/s to 10°C/s, more preferably it is from 0.2°C/s to 5°C/s, even more preferably it is from 0.5°C/s to 2°C/s.
In a preferred embodiment, the reaction mixture is cooled down to the temperature less than 220°C, more preferably in the rage from 220°C to 0°C, even more preferably from 210°C to 180°C, furthermore preferably from 205°C to 195°C.
Step (h)
In a preferred embodiment of the present invention, the cooling rate in step (h) is in the range from 0.01 °C/s to 10°C/s, preferably it is from 0.05°C/s to 5°C/s, more preferably it is from 0.1 °C/s to 1 °C/s, even more preferably it is from 0.2°C/s to 0.7°C/s.
-Shell formation process
In another aspect, the present invention also relates to a process for synthesizing a semiconducting light emitting nanoparticle comprising at least following steps (i) and (j), (i) mixing a first semiconducting material, preferably it is obtained in the step (h), and at least a first cation shell precursor and a first anion shell precursor, optionally in a solvent, to form a shell layer onto the first semiconducting material,
(j) quenching a shell formation of step (d), wherein said first cation shell precursor is a salt of an element of the group 12 of the periodic table and the first anion shell precursor is a source of an element of the group 16 of the periodic table, more preferably said first cation shell precursor is selected from one or more member s of the group consisting of Zn-stearate, Zn-myristate, Zn-oleate, Zn-laurate, Zn-palmitate, Zn-acetylacetonate, Cd-stearate, Cd-myristate, Cd-oleate, Cd-laurate, Cd- palmitate, Cd-acetylacetonate a metal halogen represented by chemical formula (III) and a metal carboxylate represented by chemical formula (IV),
MX2n (III) wherein M is Zn2+, or Cd2+, preferably M is Zn2+, X2 is a halogen selected from the group consisting of Cl , Br and I , n is 2,
[M(02CR1) (02CR2)] - (IV) wherein M is Zn2+, or Cd2+, preferably M is Zn2+;
R1 is a linear alkyl group having 1 to 30 carbon atoms, a branched alkyl group having 4 to 30 carbon atoms, a linear alkenyl group having 2 to 30 carbon atoms, or a branched alkenyl group having 4 to 30 carbon atoms, preferably R1 is a linear alkyl group having 1 to 30 carbon atoms, or a linear alkenyl group having 2 to 30 carbon atoms, more preferably, R1 is a linear alkyl group having 5 to 25 carbon atoms, or a linear alkenyl group having 6 to 25 carbon atoms, even more preferably R1 is a linear alkyl group having 10 to 20 carbon atoms, or a linear alkenyl group having 10 to 20 carbon atoms, furthermore preferably R1 is a linear alkenyl group having 10 to 20 carbon atoms, R2 is a linear alkyl group having 1 to 30 carbon atoms, a branched alkyl group having 4 to 30 carbon atoms, a linear alkenyl group having 2 to 30 carbon atoms, or a branched alkenyl group having 4 to 30 carbon atoms, preferably R2 is a linear alkyl group having 1 to 30 carbon atoms, or a linear alkenyl group having 2 to 30 carbon atoms, more preferably R2 is a linear alkyl group having 5 to 25 carbon atoms, or a linear alkenyl group having 6 to 25 carbon atoms, even more preferably R2 is a linear alkyl group having 10 to 20 carbon atoms, or a linear alkenyl group having 10 to 20 carbon atoms, furthermore preferably R2 is a linear alkenyl group having 10 to 20 carbon atoms, and preferably said anion precursor is selected from one or more members of the group consisting of Trioctylphosphine : Se, Tributylphosphine : Se, Trioctylphosphine : S, Tributylphosphine : S, and thiols. -Step (i)
According to the present invention, in some embodiments, the molar ratio of total shell precursors used in step (i) and total first semiconducting material used in step (i) is 6 or more, preferably in the range from 7 to 30, more preferably from 8 to 30, even more preferably from 9 to 27.
In some embodiments of the present invention, at least said first anion shell precursor and a second anion shell precursor are added sequentially in step (i). In some embodiments of the present invention, the first anion shell precursor and a second anion shell precursor are added in step (i) and said first anion shell precursor is Trioctylphosphine : Se, or Tributylphosphine : Se, and the second anion shell precursor is Trioctylphosphine : S,
Tributylphosphine : S, or a thiol.
In some embodiments of the present invention, said first semiconducting nanosized material in step (i) comprises at least a 1st element of group 13 elements of the periodic table and a 2nd element of the group 15 elements of the periodic table, preferably said 1st element of the group 13 elements of the periodic table is selected from In and/or Ga, and said 2nd element in group 15 elements of the periodic table is As, P, or Sb.
In some embodiments of the present invention, the first semiconducting nanosized material in step (i) further comprises a chemical element in group 12 of the periodic table selected from Zn or Cd. In a preferable embodiment, the first semiconducting nanosized material used in step (i) comprises at least InP, such as InP, InZnP, InGaP,
InGaZnP, InPZnS, or InPZnSe.
In some embodiments of the present invention, Zn atom is directly onto the surface of the first semiconducting nanosized material or alloyed with InP. The ratio between Zn and In is in the range between 0.05 and 5. Preferably, between 0.3 and 1 , in case Zn atom is included.
It is believed that the first semiconducting material obtained in step (h) shows better good size distribution, better FWHM value, and/or better Max/Min ratio of the absorption spectra.
In a preferred embodiment of the present invention, the first semiconducting materials is obtained in step (h) of the process of the present invention.
Alternatively, in some embodiments of the present invention, the first semiconducting nanosized material such as InP, InZnP, InGaP, InGaZnP, InPZnS, or InPZnSe, can be made by reacting at least one indium precursor and at least one phosphor precursor or using or a magic sized cluster. Preferably said indium precursor is a metal halide represented by following chemical formula (VI), metal carboxylate represented by following chemical formula (VII), or a combination of these, and said phosphor precursor is an amino phosphine represented by following chemical formula (VIII), tris trimethyl silyl phosphine, or a combination of these, lnX1 3 (VI)
wherein X1 is a halogen selected from the group consisting of Cl , Br and I ,
[ln(02CR3)3] - (VII) wherein R3 is a linear alkyl group having 1 to 30 carbon atoms, a branched alkyl group having 4 to 30 carbon atoms, a linear alkenyl group having 2 to 30 carbon atoms, or a branched alkenyl group having 4 to 30 carbon atoms, preferably R3 is a linear alkyl group having 1 to 30 carbon atoms, or a linear alkenyl group having 2 to 30 carbon atoms, more preferably, R3 is a linear alkyl group having 5 to 25 carbon atoms, or a linear alkenyl group having 6 to 25 carbon atoms, even more preferably R3 is a linear alkyl group having 10 to 20 carbon atoms, or a linear alkenyl group having 10 to 20 carbon atoms, furthermore preferably R3 is a linear alkenyl group having 10 to 20 carbon atoms,
(R4R5N)sP (VIII) wherein R4 and R5 are at each occurrence, independently or dependently, a hydrogen atom or a linear alkyl group having 1 to 25 carbon atoms or a linear alkenyl group having 2 to 25 carbon atoms, preferably a linear alkyl group having 1 to 10 carbon atoms, more preferably a linear alkyl group having 2 to 4 carbon atoms, even more preferably a linear alkyl group having 2 carbon atoms, more preferably said zinc salt is represented by following chemical formula (IX),
ZnX2n (IX)
wherein X2 is a halogen selected from the group consisting of Cl , Br and I , n is 2.
According to the present invention, in some embodiments, said a lll-V magic sized cluster (MSC) can be selected from the group consisting of InP, InAs, InSb, GaP, GaAs, and GaSb, magic sized clusters (MSC), preferably InP magic sized cluster (MSC InP), more preferably, it is ln37P2o(02CR1)5i, wherein said O2CR1 of said ln37P2o(02CR1)si is -
02CCH2Phenyl, or a substituted or unsubstituted fatty acid such as hexanoate, heptanoate, octanoate, nonanoate, decanoate, undecanoate, dodecanoate, tridecanoate, tetradecanoate, pentadecanoate,
hexadecanoate, heptadecanoate, octadecanoate, non-adecanoate, icosanoate or oleate.
Such InP magic sized clusters (MSCs) as single source precursors (SSP) can be fabricated as described in D. Gary et al., Chem. Mater., 2015, 1432.
- Solvent
In some embodiment of the present invention, said solvent in step (i) is selected from one or more members of the group consisting of squalenes, squalanes, heptadecanes, octadecanes, octadecenes, nonadecanes, icosanes, henicosanes, docosanes, tricosanes, pentacosanes,
hexacosanes, octacosanes, nonacosanes, triacontanes, hentriacontanes, dotriacontanes, tritriacontanes, tetratriacontanes, pentatriacontanes, hexatriacontanes, oleylamines, and trioctylamines, with preferably being of squalene, squalane, heptadecane, octadecane, octadecene, nonadecane, icosane, henicosane, docosane, tricosane, pentacosane, hexacosane, octacosane, nonacosane, triacontane, hentriacontane, dotriacontane, tritriacontane, tetratriacontane, pentatriacontane, hexatriacontane, oleylamine, and trioctylamine, more preferably squalane, pentacosane, hexacosane, octacosane, nonacosane, or triacontane, even more preferably squalane, pentacosane, or hexacosane.
In some embodiments, alkyl chain lengths of said solvent can be C1 to C30, and the chain can be linear or branched.
- Cation precursors for coating of second semiconducting material as a shell layer
According to the present invention, as a cation precursor for formation of the second semiconducting nanosized material as a shell layer, one or more of known cation precursors for shell layer synthesis comprising group 12 element of the periodic table or 13 elements of the periodic table can be used preferably.
In some embodiments, the metal halides and the cation precursor can be mixed, or, the metal halide can be used as a single cation precursor instead of the cation precursor which is mentioned in the column of cation precursors for formation of the second semiconducting material, if necessary.
- Anion precursors for formation of the second semiconducting material According to the present invention, as an anion precursor for formation of the second semiconducting material (shell layer coating), known anion precursor for shell layer synthesis comprising a group 16 element of the periodic table can be used preferably. For example, as a first and a second anion precursor for formation of the second semiconducting material can be selected from one or more members of the group consisting of Se anion: Se, Se-trioctylphopshine, Se- tributylphosphine, Se-oleylamine complex, Selenourea, Se-octadecene complex, Se-octadecene suspension, S anion and thiols such as
octanethiol, dodecanthiol, ter-doedecanthiol,: S, S-trioctylphopshine, S- tributylphosphine, S-oleylamine complex, Selenourea, S-octadecene complex, and S-octadecene suspension, Te anion: Te, Te- trioctylphopshine, Te- tributylphosphine, Te-oleylamine complex,
Telenourea, Te-octadecene complex, and Te-octadecene suspension.
In some embodiments of the present invention, at least said first anion precursor and a second anion precursor are added simultaneously in the process of formation of the second semiconducting material, preferably said first anion precursor is selected from the group consisting of Se anion: Se, Se-trioctylphopshine, Se- tributylphosphine, Se-oleylamine complex, Selenourea, Se-octadecene complex, and Se-octadecene suspension, and the second anion shell precursor is selected from the group consisting of S anion: S, S-trioctylphopshine, S- tributylphosphine, S-oleylamine complex, Selenourea, S-octadecene complex, and S-octadecene suspension, Te anion: Te, Te-trioctylphopshine, Te- tributylphosphine, Te-oleylamine complex, Telenourea, Te-octadecene complex, and Te-octadecene suspension.
Without wishing to be bound to the theory, it is believed that the addition of said first anion precursor and a second anion precursor may lead graded shell due to the reason that the reaction speed of Se anion and the reaction speed of S or Te are different of each other.
In some embodiments of the present invention, at least said first anion precursor and a second anion precursor are added sequentially in step of the formation of the second semiconducting material, preferably said first anion precursor is selected from the group consisting of Se anion: Se, Se- trioctylphopshine, Se- tributylphosphine, Se-oleylamine complex,
Selenourea, Se-octadecene complex, and Se-octadecene suspension, and the second anion precursor is selected from the group consisting of S anion: S, S-trioctylphopshine, S- tributylphosphine, S-oleylamine complex, Selenourea, S-octadecene complex, and S-octadecene suspension, Te anion: Te, Te-trioctylphopshine, Te- tributylphosphine, Te-oleylamine complex, Telenourea, Te-octadecene complex, and Te-octadecene suspension.
By changing the reaction temperature in step of the formation of the second semiconducting material, and total amount of precursors used in the step, the volume ratio between the first semiconducting nanosized material and the shell is more preferably controlled.
In a preferred embodiment of the present invention, step (i) is carried out at 250 °C or more, preferably, it is in the range from 250°C to 350°C, more preferably, from 280°C to 320°C to realize better shell / first semiconducting nanosized material volume ratio and lower self-absorption value of the semiconducting light emitting nanoparticle.
Other conditions for formation of the second semiconducting material are described for example in US8679543 B2 and Chem. Mater. 2015, 27, pp 4893-4898.
It is believed that this process can also control the crystallinity of the shell layer. For example, it is believed that highly crystalline ZnSe shell is obtained using this process. -Treatment process
According to the present invention, in some embodiments, the process further comprises following step (k) before step (i), (k) subjecting said a first semiconducting material to a surface treatment with a metal halide represented by following chemical formula (III), MX2n (III) wherein M is Zn2+, or Cd2+, preferably M is Zn2+, X2 is a halogen selected from the group consisting of Cl , Br and I , n is 2. In a preferred embodiment of the present invention, the step (k) is carried out at the temperature in the range from 150°C to 350°C, preferably in the range from 200°C to 320 °C, more preferably in the range from 250°C to 300°C, even more preferably from 250°C to 280°C. In a preferred embodiment of the present invention, the treatment time of step (k) is in the range from 10 minutes to 10 hours, preferably from 20 minutes to 4 hours, more preferably 30 minutes to 3 hours.
In a preferred embodiment of the present invention, the total molar ratio between the amount of the metal halide in step (k) and the amount of the first semiconducting material is in the range from 500 to 50.000, preferably from 1.000 to 20.000, more preferably from 2.000 to 10.000.
Preferably, the total molar ratio between the amount of the metal halide in step (k) and the amount of InP core as the first semiconducting material is in the range from 500 to 50.000, preferably from 1.000 to 20.000, more preferably from 2.000 to 10.000.
According to the present invention, in some embodiments, step (k) is carried out in a solution comprising at least one solvent selected from one or more members of the group consisting of squalenes, squalanes, heptadecanes, octadecanes, octadecenes, nonadecanes, icosanes, henicosanes, docosanes, tricosanes, pentacosanes, hexacosanes, octacosanes, nonacosanes, triacontanes, hentriacontanes, dotriacontanes, tritriacontanes, tetratriacontanes, pentatriacontanes, hexatriacontanes, oleylamines, and trioctylamines, with preferably being of squalene, squalane, heptadecane, octadecane, octadecene, nonadecane, icosane, henicosane, docosane, tricosane, pentacosane, hexacosane, octacosane, nonacosane, triacontane, hentriacontane, dotriacontane, tritriacontane, tetratriacontane, pentatriacontane, hexatriacontane, oleylamine, and trioctylamine, more preferably squalane, pentacosane, hexacosane, octacosane, nonacosane, or triacontane, even more preferably squalane, pentacosane, or hexacosane.
- Cleaning process
According to the present invention, in some embodiments, the process can optionally comprise following cleaning step (I), preferably cleaning step (I) is carried out after step (k) before step (i),
(I) cleaning the first semiconducting material with a cleaning solution, preferably said cleaning solution comprises at least one solvent selected from one or more members of the group consisting of ketones, such as, methyl ethyl ketone, acetone, methyl amyl ketone, methyl isobutyl ketone, and cyclohexanone; alcohols, such as, methanol, ethanol, propanol, butanol, hexanol, cyclo hexanol, ethylene glycol; hexane; chloroform;
xylene and toluene, preferably alcohol and toluene, more preferably ethanol and toluene.
In some embodiments of the present invention, step (I) is carried out at the temperature in the range of from 0°C to 100°C, preferably from 5 to 60°C, more preferably from 10 to 40°C to clean the first semiconducting
nanosized material effectively. In some embodiment of the present invention, the step (I) comprises following step (11 ),
(11 ) making a mixture solution by mixing the obtained solution from step (h) and a cleaning solution of the present invention, to make a suspension in the mixture solution and to separate unreacted first semiconducting nanosized material precursors and ligands from the suspension.
In a preferred embodiment of the present invention, the step (I) further comprises following step (I2),
(12) extracting the suspension and dispersing it in a solvent, preferably centrifuging the suspension to extract the suspension and dispersing the centrifuged suspension in a solvent.
In a preferred embodiment of the invention, the solvent in step (I2) is selected from the solvent described in the section of "Solvent” above.
- Cleaning solution
In some embodiments of the present invention, the cleaning solution for step (k) comprises at least one solvent selected from one or more members of the group consisting of ketones, such as, methyl ethyl ketone, acetone, methyl amyl ketone, methyl isobutyl ketone, and cyclohexanone; alcohols, such as, methanol, ethanol, propanol, butanol, hexanol, cyclo hexanol, ethylene glycol; hexane; chloroform; acetonitrile; xylene and toluene.
In a preferred embodiment of the present invention, the cleaning solution is selected from one or more members of the group consisting of ketones, such as, methyl ethyl ketone, acetone, methyl amyl ketone, methyl isobutyl ketone, and cyclohexanone; alcohols, such as, methanol, ethanol, propanol, butanol, hexanol, cyclo hexanol, ethylene glycol; hexane;
chloroform; xylene and toluene. In a preferred embodiment of the present invention, in step (I), to more effectively remove unreacted first semiconducting nanosized material precursors from the solution obtained in step (h) and remove the ligands leftovers in the solution, cleaning solution comprises one or more of alcohols is used.
More preferably, the cleaning solution contains one or more of alcohols selected from the group consisting of acetonitrile, methanol, ethanol, propanol, butanol, and hexanol, and one more solution selected from xylene or toluene to remove unreacted first semiconducting nanosized material precursors from the solution obtained in step (h) and remove the ligands leftovers in the solution effectively. More preferably, the cleaning solution contains one or more of alcohols selected from methanol, ethanol, propanol, and butanol, and toluene.
In some embodiments of the present invention, the mixing ratio of alcohols and toluene or xylene can be in the range from 1 :1 - 20:1 in a molar ratio. Preferably it is from 5:1 to 10:1 , to remove unreacted first semiconducting nanosized material precursors from the solution obtained in step (h) and to remove the ligands leftovers in the solution.
More preferably, the cleaning solution removes the extra ligands and the un reacted precursor.
-Photo irradiation process
According to the present invention, in some embodiments, the process further comprises following step (m), preferably step (m) is carried out after step (i), more preferably after step (I). (m) Irradiating light with a peak light wavelength in the range from 300 to 650 nm to the semiconducting light emitting nanoparticle, preferably in the range from 320 to 520nm, more preferably from 350nm to 500 nm, even more preferably at 360nm to 470nm, preferably in the presence of zinc containing organic material selected from one or more member of the group consisting of zinc carboxylates, zinc phosphonates, zinc xanthates, and zinc dithiocarbamates.
In a preferred embodiment of the present invention, the intention of the light irradiation is in the range from 0,025 to 1 watt/cm2, preferably it is in the range from 0.05 to 0.5 watt/cm2.
In a preferred embodiment of the present invention, at least one of the steps of the process is carried out in an inert condition, such as ish atmosphere, preferably all the steps are carried out in said inert condition.
-Semiconducting material
In another aspect, the present invention also relates to a semiconducting material obtainable or obtained from the process comprising steps (a) to (h) of the present invention.
-Semiconducting light emitting nanoparticle
In another aspect, the present invention also relates to a semiconducting nanoparticle obtainable or obtained from the process comprising steps of (i) and (j) of the present invention.
In some embodiments of the present invention, the value of the ratio of the exciton absorption peak and the exciton absorption minimum of said semiconductor nanoparticle, is 1.3 or more, preferably is 1.6 or more, more preferably 1.7 or more, even more preferably 1.8 or more.
Composition In another aspect, the present invention also relates to composition comprising at least one semiconducting light emitting nanoparticle of the present invention, or at least one semiconducting material of the present invention, and at least one additional material, preferably the additional material is selected from the group consisting of organic light emitting materials, inorganic light emitting materials, charge transporting materials, scattering particles, and matrix materials, preferably the matrix materials are optically transparent polymers.
For example, said activator can be selected from the group consisting of Sc3+,Y3+, La3+, Ce3+, Pr3+, Nd3+, Pm3+, Sm3+, Eu3+, Gd3+, Tb3+, Dy3+, Ho3+, Er3+, Tm3+, Yb3+, Lu3+, Bi3+, Pb2+, Mn2+, Yb2+, Sm2+, Eu2+, Dy2+, Ho2+ and a combination of any of these, and said inorganic fluorescent material can be selected from the group consisting of sulfides, thiogallates, nitrides, oxynitrides, silicate, aluminates, apatites, borates, oxides, phosphates, halo phosphates, sulfates, tungstenates, tantalates, vanadates, molybdates, niobates, titanates, germinates, halides based phosphors, and a
combination of any of these.
Such suitable inorganic fluorescent materials described above can be well known phosphors including nanosized phosphors, quantum sized materials like mentioned in the phosphor handbook, 2nd edition (CRC Press, 2006), pp. 155 - pp. 338 (W.M.Yen, S.Shionoya and FI .Yamamoto),
WO201 1 /147517A, WO2012/034625A, and WO2010/095140A.
According to the present invention, as said organic light emitting materials, charge transporting materials, any type of publicly known materials can be used preferably. For example, well known organic fluorescent materials, organic host materials, organic dyes, organic electron transporting materials, organic metal complexes, and organic hole transporting materials.
For examples of scattering particles, small particles of inorganic oxides such as S1O2, Sn02, CuO, CoO, AI2O3 T1O2, Fe203, Y2O3, ZnO, MgO;
organic particles such as polymerized polystyrene, polymerized PMMA; inorganic hollow oxides such as hollow silica or a combination of any of these; can be used preferably. - Matrix material
According to the present invention, a wide variety of publicly known transparent matrix materials suitable for optical devices can be used preferably. According to the present invention, the term“transparent” means at least around 60 % of incident light transmit at the thickness used in an optical medium and at a wavelength or a range of wavelength used during operation of an optical medium. Preferably, it is over 70 %, more preferably, over 75%, the most preferably, it is over 80 %.
In a preferred embodiment of the present invention, as said matrix material, any type of publicly known transparent matrix material, described in for example, WO 2016/134820A can be used. In some embodiments of the present invention, the transparent matrix material can be a transparent polymer.
According to the present invention the term“polymer” means a material having a repeating unit and having the weight average molecular weight (Mw) 1000 g/mol, or more. The molecular weight Mw is determined by means of GPC (= gel
permeation chromatography) against an internal polystyrene standard.
In some embodiments of the present invention, the glass transition temperature (Tg) of the transparent polymer is 70 °C or more and 250 °C or less.
Tg is measured based on changes in the heat capacity observed in
Differential scanning colorimetry like described in
http://pslc.ws/macroq/dsc.htm; Rickey J Seyler, Assignment of the Glass Transition, ASTM publication code number (PCN) 04-012490-50.
For example, as the transparent polymer for the transparent matrix material, poly(meth)acrylates, epoxys, polyurethanes, polysiloxanes, can be used preferably.
In a preferred embodiment of the present invention, the weight average molecular weight (Mw) of the polymer as the transparent matrix material is in the range from 1 ,000 to 300,000 g/mol, more preferably it is from 10,000 to 250,000 g/mol.
In a preferable embodiment of the present invention, the composition comprises a plural of the light emitting nanoparticles and/or a plural of the semiconducting materials.
- Formulation
In another aspect, the present invention relates to formulation comprising at least one semiconducting light emitting nanoparticle or the composition of the present invention,
and at least one solvent. Preferably the solvent is selected from one or more members of the group consisting of aromatic, halogenated and aliphatic hydrocarbon solvents, more preferably selected from one or more members of the group consisting of toluene, xylene, ethers, tetrahydrofuran, chloroform, dichloromethane and heptane, purified water, ester acetates, alcohols, sulfoxides, formamides, nitrides, ketones.
The amount of the solvent in the formulation can be freely controlled according to the method of coating the composition. For example, if the composition is to be spray-coated, it can contain the solvent in an amount of 90 wt. % or more. Further, if a slit-coating method, which is often adopted in coating a large substrate, is to be carried out, the content of the solvent is normally 60 wt. % or more, preferably 70 wt. % or more. In some embodiments of the present invention, the formulation comprises a plural of the semiconducting light emitting nanoparticles and/or a plural of the semiconducting materials.
- Use
In another aspect, the present invention relates to use of the
semiconducting light emitting nanoparticle, or the semiconducting material, or the composition, or the formulation, in an electronic device, optical device or in a biomedical device. - Optical medium
In another aspect, the present invention further relates to an optical medium comprising at least one semiconducting light emitting nanoparticle of the present invention, or at least one semiconducting material of the present invention, or the composition. ln some embodiments of the present invention, the optical medium can be an optical sheet, for example, a color filter, color conversion film, remote phosphor tape, or another film or filter.
According to the present invention, the term "sheet” includes film and / or layer like structured mediums.
In some embodiments of the present invention, the optical medium comprises an anode and a cathode, and at least one organic layer comprising at least one light emitting nanoparticle or the composition of the present invention, preferably said one organic layer is a light emission layer, more preferably the medium further comprises one or more additional layers selected from the group consisting of hole injection layers, hole transporting layers, electron blocking layers, hole blocking layers, electron blocking layers, and electron injection layers.
According to the present invention, any kinds of publicly available inorganic, and/or organic materials for hole injection layers, hole transporting layers, electron blocking layers, light emission layers, hole blocking layers, electron blocking layers, and electron injection layers can be used preferably, like as described in WO 2018/024719 A1 , US2016/233444 A2, US7754841 B, WO 2004/037887 and WO 2010/097155.
In a preferable embodiment of the present invention, the optical medium comprises a plural of the light emitting nanoparticles and/or a plural of the semiconducting materials.
Preferably, the anode and the cathode of the optical medium sandwich the organic layer.
More preferably said additional layers are also sandwiched by the anode and the cathode. In some embodiments of the present invention, the organic layer comprises at least one light emitting nanoparticle of the present invention, and a host material, preferably the host material is an organic host material.
For examples, as described in working example 13, the optical medium can comprise at least a substrate;
- an anode such as ITO layer;
- optionally a buffer layer;
- hole transporting layer (HTL);
- emission layer (EML);
- electron injection layer (EIL) and/or electron transporting layer (ETL);
- a cathode such as Al layer;
wherein said emission layer comprises at least one light emitting
nanoparticle.
- Optical device
In another aspect, the invention further relates to an optical device comprising the optical medium.
In some embodiments of the present invention, the optical device can be a liquid crystal display device (LCD), Organic Light Emitting Diode (OLED), backlight unit for an optical display, Light Emitting Diode device (LED), Micro Electro Mechanical Systems (here in after“MEMS”), electro wetting display, or an electrophoretic display, a lighting device, and / or a solar cell.
For examples, said optical device configured so that the optical device can emit light, and it comprises an optical medium including at least a substrate;
- an anode such as ITO layer;
- optionally a buffer layer;
- hole transporting layer (HTL);
- emission layer (EML); - electron injection layer (EIL) and/or electron transporting layer (ETL);
- a cathode such as Al layer;
wherein said emission layer comprises at least one light emitting
nanoparticle;
and
- additional optical layer such as glass substrate, a color filter, polarizer such as a linear polarizer, circular polarizer, antireflection layer and light direction changing layer. Technical effects
The present invention provides one or more of following effects;
improvement of particle size distribution, better Full Width at Half Maximum (FWHM) value, improved self-absorption value, improvement of quantum yield of nanoparticle, lowering trap emission of nanoparticle, optimizing the interface between core and shell layers, optimizing a surface condition of core part of nanoparticle, reducing lattice defects of cores and/or shell layers of nanoparticle, realizing a better light emission of nanoparticle with our without shell layers, optimizing fabrication process of nanoparticle, providing new fabrication process to improve size control of nanoparticle, environmentally more friendly and safer fabrication process.
Preferable embodiments 1. A semiconducting light emitting nanoparticle comprising at least a first semiconducting material comprising at least a 1st element of group 13 elements of the periodic table and a 2nd element of the group 15 elements of the periodic table, and at least one shell layer comprising at least a 3rd element of the group 12 elements of the periodic table and a 4th element of the group 16 elements of the periodic table, wherein the nanoparticle has the self-absorption value 0.35 or less, preferably it is in the range from 0.30 to 0.01 , more preferably from 0.25 to 0.05, even more preferably from 0.23 to 0.12, and the Full Width at Half Maximum 46 nm or less, preferably it is in the range from 46 nm to 20 nm, more preferably from 40 nm to 25 nm, even more preferably from 38 nm to 30 nm. 2.The nanoparticle according to embodiment 1 , wherein the nanoparticle has the trap emission 15 % or less, preferably 10% or less, more preferably it is in the range from 8% to 5%.
3.The nanoparticle according to embodiment 1 or 2, wherein the
nanoparticle emits light having the peak maximum light emission
wavelength in the range from 520nm to 700nm, preferably from 550nm to 650nm, more preferably from 580nm to 650nm.
4.The nanoparticle according to any one of embodiments 1 to 3, wherein the average size of the first semiconducting material is in the range from 1 to 4 nm, preferably it is in the range from 2.5 to 4.0, more preferably from 2.7 to 3.6.
5.The nanoparticle according to any one of embodiments 1 to 4, wherein the size distribution of the first semiconducting material is 10% or less, preferably it is in the range from 10% to 3%, more preferably from 8% to 4%.
6.The nanoparticle according to any one of embodiments 1 to 5, where the volume ratio between the shell layer and the first semiconducting material is
5 or more, preferably it is in the range from 5 to 40, more preferably it is from 10 to 30. 7. A semiconducting light emitting nanoparticle comprising at least a first semiconducting material comprising at least a 1st element of group 13 elements of the periodic table and a 2nd element of the group 15 elements of the periodic table, and at least one shell layer comprising at least a 3rd element of the group 12 elements of the periodic table and a 4th element of the group 16 elements of the periodic table, wherein the size distribution of the first semiconducting material is 10% or less, preferably in the range from 10% to 3%, more preferably from 8% to 4%, and the volume ratio between the shell layer and the first semiconducting material is 5 or more, preferably it is in the range from 5 to 40, more preferably it is from 10 to 30.
8.The nanoparticle according to any one of embodiments 1 to 7, wherein the shell layer is represented by following formula (II),
MSei-zSz (II) wherein M is Zn2+, or Cd2+, preferably M is Zn2+; 0£z<1 , preferably 0<z<1.
9.The nanoparticle according to any one of embodiments 1 to 8, wherein the ratio of Se and S elements in the shell layer is in the range from 0.6 to 4.0, preferably it is in the range from 0.7 to 3.0, more preferably it is in the range from 0.8 to 2.5, even more preferably from 1.0 to 2.0.
10. A semiconducting light emitting nanoparticle comprising at least a first semiconducting material comprising at least a 1st element of group 13 elements of the periodic table and a 2nd element of the group 15 elements of the periodic table, and at least one shell layer, wherein the shell layer is represented by following formula (II),
MSei-zSz (I I) wherein M is Zn2+, or Cd2+, preferably M is Zn2+; 0<z<1 , and the ratio of Se and S elements in the shell layer is in the range from 0.6 to 4.0, preferably it is in the range from 0.7 to 3.0, more preferably it is in the range from 0.8 to 2.5, even more preferably from 1.0 to 2.0. 11. The nanoparticle according to any one of embodiments 1 to 10, wherein the concentration of Se in the shell layer varies from a high concentration of the first semiconducting material side in the shell layer to a low
concentration of the opposite side in the shell layer, more preferably, the concentration of S in the shell layer varies from a low concentration of first semiconducting material side of the shell layer to a higher concentration to the opposite side of the shell layer.
12. The nanoparticle according to any one of embodiments 1 to 11 , wherein the semiconducting light emitting nanoparticle further comprises a 2nd shell layer onto said shell layer.
13. The nanoparticle according to any one of embodiments 1 to 12, wherein the first semiconducting material is represented by following chemical formula (I),
I n ( 1 -x-2/3y)G a XZ n ySzSeq P ( 1 -2/3z-2/3q ) ( I ) wherein 0<x<1 , 0<y<1 , 0<z<1 , 0<q<1 , 0<x+y<1
14. The nanoparticle according to any one of embodiments 1 to 13, wherein the first semiconducting material has the value of the ratio of the exciton absorption peak and exciton absorption minimum of said first
semiconducting material 1.6 to 3 at exciton wavelength 570 nm or more, preferably 1.6 to 2.5 at exciton wavelength in the range from 570 nm to 600 nm, preferably in the range 1.6 to 2 at exciton wavelength in the range from 565 nm to 600 nm, even more preferably in the range 1.6 to 1.8 at exciton wavelength in the range from 570nm to 580 nm.
15. The nanoparticle according to any one of embodiments 1 to 14, where the nanoparticle further comprises a zinc containing organic material selected from the group consisting of zinc carboxylates, zinc phosphonates, zinc xanthates, zinc dithiocarbamates, preferably the first semiconducting material, the shell layer and the zinc containing organic material is placed in this sequence.
16. A process for synthesizing a semiconducting nanoparticle comprising following steps (a) to (h),
(a) mixing a semiconductor nanosized cluster and an another compound or to an another mixture of compounds at a temperature in the range from 260 to 500°C in order to get a reaction mixture, preferably said temperature is in the range from 300 to 460°C, more preferably from 330 to 430°C, even more preferably from 360 to 400°C,
(b) cooling the reaction mixture to slow down or stop the growth of a first semiconducting material in step (a),
(c) adjusting or keeping the temperature of the reaction mixture from step (b) in the range from 40 °C to 300 °C, preferably in the range from 50 °C to 290 °C, more preferably from 60 °C to 280 °C, furthermore preferably from 65 °C to 270°C to allow a growth of a first semiconducting material in the mixture, (d) adding a semiconductor nanosized cluster to the reaction mixture,
(e) adjusting or keeping the temperature of the reaction mixture from step
(d) in the range from 40 °C to 300 °C, preferably in the range from 50 °C to 290 °C, more preferably it is from 60 °C to 280 °C, furthermore preferably from 65 °C to 270°C to allow a growth of a first semiconducting material in the mixture,
(f) optionally repeating steps (d) and (e), (g) adjusting or keeping the temperature of the reaction mixture from step
(e) or (f) in the range from 200 °C to 350 °C, preferably in the range from 230 °C to 320 °C, more preferably it is from 240°C to 310 °C, furthermore preferably from 250°C to 300°C to allow growth of a first semiconducting material in the mixture,
(h) cooling the reaction mixture to stop the growth of first semiconducting material in step (e) or step (f).
17. The process of embodiment 16, wherein the said another compound is a solvent.
18. The process according to embodiment 16 or 17, wherein said another compound is a solvent having the boiling point 250 °C or more, preferably in the range from 250 °C to 500 °C, more preferably in the range from 300 °C to 480 °C, even more preferably from 350 °C to 450 °C, furthermore preferably it is from 370°C to 430 °C. 19.The process according to any one of embodiments 16 to 18, wherein said another compound is a solvent selected from one or more members of the group consisting of squalenes, squalanes, heptadecanes, octadecanes, octadecenes, nonadecanes, icosanes, henicosanes, docosanes, tricosanes, pentacosanes, hexacosanes, octacosanes, nonacosanes, triacontanes, hentriacontanes, dotriacontanes, tritriacontanes,
tetratriacontanes, pentatriacontanes, hexatriacontanes, oleylamines, and trioctylamines, with preferably being of squalene, squalane, heptadecane, octadecane, octadecene, nonadecane, icosane, henicosane, docosane, tricosane, pentacosane, hexacosane, octacosane, nonacosane,
triacontane, hentriacontane, dotriacontane, tritriacontane, tetratriacontane, pentatriacontane, hexatriacontane, oleylamine, and trioctylamine, more preferably squalane, pentacosane, hexacosane, octacosane, nonacosane, or triacontane, even more preferably squalane, pentacosane, or
hexacosane.
20. The process according to any one of embodiments 16 to 19, wherein the temperature of the reaction mixture in step (a) is kept in the temperature range for from 1 second to 10 minutes, preferably from 5 seconds to 5 minutes, more preferably from 10 seconds to 200 seconds, more preferably from 20 seconds to 160 seconds.
21. The process according to any one of embodiments 16 to 20, wherein the total amount of the inorganic part of said lll-V semiconductor nanosized clusters in step (a) is in the range from 0.1x1 O 4 to 1x1 O 3 mol%, preferably being of the amount in the range from 0.5x1 O 4 to 5x1 O 4 mol%, more preferably from 1x1 O 4 to 3x1 O 4 mol% of the reaction mixture.
22.The process according to any one of embodiments 16 to 21 , wherein the cooling rate in step (b) is in the range from 0.05°C/s to 50°C/s, preferably it is from 0.1 °C/s to 10°C/s, more preferably it is from 0.2°C/s to 5°C/s, even more preferably it is from 0.5°C/s to 2°C/s. 23. The process according to any one of embodiments 16 to 22, wherein the cooling rate in step (h) is in the range from 0.01 °C/s to 10°C/s, preferably it is from 0.05°C/s to 5°C/s, more preferably it is from 0.1 °C/s to 1 °C/s, even more preferably it is from 0.2°C/s to 0.7°C/s.
24. A process for synthesizing a semiconducting light emitting nanoparticle comprising following steps (i) and (j), (i) mixing a first semiconducting material, preferably it is obtained in the step (h) according to any one of claims 16 to 23, and at least a first cation shell precursor and a first anion shell precursor, optionally in a solvent, to form a shell layer onto the first semiconducting material, (j) quenching a shell formation of step (d), wherein said first cation shell precursor is a salt of an element of the group 12 of the periodic table and the first anion shell precursor is a source of an element of the group 16 of the periodic table, more preferably said first cation shell precursor is selected from one or more member s of the group consisting of Zn-stearate, Zn-myristate, Zn-oleate, Zn-laurate, Zn-palmitate, Zn-acetylacetonate, Cd-stearate, Cd-myristate, Cd-oleate, Cd-laurate, Cd- palmitate, Cd-acetylacetonate a metal halogen represented by chemical formula (III) and a metal carboxylate represented by chemical formula (IV),
MX2n (III) wherein M is Zn2+, or Cd2+, preferably M is Zn2+, X2 is a halogen selected from the group consisting of Cl , Br and I , n is 2,
[M(02CR1) (O2CR2)] - (IV) wherein M is Zn2+, or Cd2+, preferably M is Zn2+;
R1 is a linear alkyl group having 1 to 30 carbon atoms, a branched alkyl group having 4 to 30 carbon atoms, a linear alkenyl group having 2 to 30 carbon atoms, or a branched alkenyl group having 4 to 30 carbon atoms, preferably R1 is a linear alkyl group having 1 to 30 carbon atoms, or a linear alkenyl group having 2 to 30 carbon atoms, more preferably, R1 is a linear alkyl group having 5 to 25 carbon atoms, or a linear alkenyl group having 6 to 25 carbon atoms, even more preferably R1 is a linear alkyl group having 10 to 20 carbon atoms, or a linear alkenyl group having 10 to 20 carbon atoms, furthermore preferably R1 is a linear alkenyl group having 10 to 20 carbon atoms,
R2 is a linear alkyl group having 1 to 30 carbon atoms, a branched alkyl group having 4 to 30 carbon atoms, a linear alkenyl group having 2 to 30 carbon atoms, or a branched alkenyl group having 4 to 30 carbon atoms, preferably R2 is a linear alkyl group having 1 to 30 carbon atoms, or a linear alkenyl group having 2 to 30 carbon atoms, more preferably R2 is a linear alkyl group having 5 to 25 carbon atoms, or a linear alkenyl group having 6 to 25 carbon atoms, even more preferably R2 is a linear alkyl group having 10 to 20 carbon atoms, or a linear alkenyl group having 10 to 20 carbon atoms, furthermore preferably R2 is a linear alkenyl group having 10 to 20 carbon atoms, and preferably said anion shell precursor is selected from one or more members of the group consisting of Trioctylphosphine : Se,
Tributylphosphine : Se, Trioctylphosphine : S, Tributylphosphine : S, and thiols. 25. The process according to embodiment 24, wherein the molar ratio of total shell precursors used in step (i) and total first semiconducting material used in step (i) is 6 or more, preferably in the range from 7 to 30, more preferably from 8 to 30, even more preferably from 9 to 27.
26.The process according to embodiment 24 or 25, wherein at least said first anion shell precursor and a second anion shell precursor are added sequentially in step (i).
27. The process according to any one of embodiments 24 to 26, wherein said first anion shell precursor is Trioctylphosphine : Se, or
Tributylphosphine : Se, and the second anion shell precursor is
Trioctylphosphine : S, Tributylphosphine : S, or a thiol.
28. The process according to any one of embodiments 24 to 27, where the process further comprises following step (k) before step (i),
(k) subjecting said a first semiconducting material to a surface treatment with a metal halide represented by following chemical formula (III),
MX2n (III) wherein M is Zn2+, or Cd2+, preferably M is Zn2+, X2 is a halogen selected from the group consisting of Cl , Br and I , n is 2.
29. The process according to any one of embodiments 24 to 28, wherein the step (k) is carried out at the temperature in the range from 150°C to
350°C, preferably in the range from 200°C to 320 °C, more preferably in the range from 250°C to 300°C, even more preferably from 250°C to 280°C.
30. The process according to any one of embodiments 24 to 29, wherein the treatment time of step (k) is in the range from 10 minutes to 10 hours, preferably from 20 minutes to 4 hours, more preferably 30 minutes to 3 hours. 31. The process according to any one of embodiments 24 to 30, wherein the treatment time of step (k) wherein the total molar ratio between the amount of the metal halide in step (k) and the amount of the first
semiconducting material is in the range from 500 to 50.000, preferably from 1.000 to 20.000, more preferably from 2.000 to 10.000.
32. The process according to any one of embodiment 24 to 31 , wherein step (k) is carried out in a solution comprising at least one solvent selected from one or more members of the group consisting of squalenes, squalanes, heptadecanes, octadecanes, octadecenes, nonadecanes, icosanes, henicosanes, docosanes, tricosanes, pentacosanes,
hexacosanes, octacosanes, nonacosanes, triacontanes, hentriacontanes, dotriacontanes, tritriacontanes, tetratriacontanes, pentatriacontanes, hexatriacontanes, oleylamines, and trioctylamines, with preferably being of squalene, squalane, heptadecane, octadecane, octadecene, nonadecane, icosane, henicosane, docosane, tricosane, pentacosane, hexacosane, octacosane, nonacosane, triacontane, hentriacontane, dotriacontane, tritriacontane, tetratriacontane, pentatriacontane, hexatriacontane, oleylamine, and trioctylamine, more preferably squalane, pentacosane, hexacosane, octacosane, nonacosane, or triacontane, even more preferably squalane, pentacosane, or hexacosane.
33. The process according to any one of embodiments 24 to 32, wherein the process further comprises following step (I) after step (k) before step (i),
(I) cleaning the first semiconducting material with a cleaning solution, preferably said cleaning solution comprises at least one solvent selected from one or more members of the group consisting of ketones, such as, methyl ethyl ketone, acetone, methyl amyl ketone, methyl isobutyl ketone, and cyclohexanone; alcohols, such as, methanol, ethanol, propanol, butanol, hexanol, cyclo hexanol, ethylene glycol; hexane; chloroform; xylene and toluene, preferably alcohol and toluene, more preferably ethanol and toluene.
34. The process according to any one of embodiments 16 to 33, further comprising a following step (m),
(m) Irradiating light with a peak light wavelength in the range from 300 to 650 nm to the semiconducting light emitting nanoparticle, preferably in the range from 320 to 520nm, more preferably from 350nm to 500 nm, even more preferably at 360nm to 470nm.
35. The process according to embodiment 34, wherein the intention of the light irradiation is in the range from 0,025 to 1 watt/cm2, preferably it is in the range from 0.05 to 0.5 watt/cm2.
36. The process according to embodiment 34 or 35, wherein the irradiation is carried out in the presence of zinc containing organic material selected from the group consisting of zinc carboxylates, zinc phosphonates, zinc xanthates, zinc dithiocarbamates.
37. A semiconducting material obtainable or obtained from the process according to any one of embodiments 16 to 23.
38. The nanoparticle according to embodiment 37, wherein the value of the ratio of the exciton absorption peak and the exciton absorption minimum of said semiconductor nanoparticle, is 1.3 or more, preferably is 1.6 or more, more preferably 1.7 or more, even more preferably 1.8 or more.
39. A semiconducting light emitting nanoparticle obtainable or obtained from the process according to any one of embodiments 24 to 36. 40. A composition comprising at least one semiconducting light emitting nanoparticle according to any one of embodiments 1 to 15, 39, or at least one semiconducting material of embodiment 37 or 38, and at least one additional material, preferably the additional material is selected from the group consisting of organic light emitting materials, inorganic light emitting materials, charge transporting materials, scattering particles, host materials, nanosized plasmonic particles, photo initiators, and matrix materials.
41. Formulation comprising at least one semiconducting light emitting nanoparticle according to any one of embodiments 1 to 15, 39, or at least one semiconducting material of embodiment 37 or 38, or a composition according to embodiment 40, and at least one solvent, preferably the solvent is selected from one or more members of the group consisting of aromatic, halogenated and aliphatic hydrocarbon solvents, more preferably selected from one or more members of the group consisting of toluene, xylene, ethers,
tetrahydrofuran, chloroform, dichloromethane and heptane, purified water, ester acetates, alcohols, sulfoxides, formamides, nitrides, ketones.
42. Use of the semiconducting light emitting nanoparticle according to any one of embodiments 1 to 15, 39, or at least one semiconducting material of embodiment 37 or 38, or a composition according to embodiment 40, or the formulation according to embodiment 41 in an electronic device, optical device or in a biomedical device.
43. An optical medium comprising at least one semiconducting light emitting nanoparticle according to any one of embodiments 1 to 15, 39, or at least one semiconducting material of embodiment 37 or 38, or a composition according to embodiment 40. 44. The optical medium of embodiment 43, comprising an anode and a cathode, and at least one organic layer comprising at least one light emitting nanoparticle according to any one of embodiments 1 to 15, 39, or at least one semiconducting material of embodiment 37 or 38, or a composition according to embodiment 40, preferably said one organic layer is a light emission layer, more preferably the medium further comprises one or more layers selected from the group consisting of hole injection layers, hole transporting layers, electron blocking layers, hole blocking layers, electron blocking layers, and electron injection layers.
45. The optical medium of embodiment 43 or 44, wherein the organic layer comprises at least one light emitting nanoparticle according to any one of embodiments 1 to 15, 33, and a host material, preferably the host material is an organic host material.
46. An optical device comprising at least said optical medium according to any one of embodiments 43 to 45.
The working examples 1 - 19 below provide descriptions of the present invention, as well as an in-detail description of their fabrication.
Working Examples
Working Example 1 : InP MSCs synthesis
a) Preparation of ln(MA)3 Solution. (MA is myristate)
0.93 g (3.20 mmol) of indium acetate and 2.65 g (11.6 mmol) of myhstic acid are weighed out into a 100 ml_, three-neck round-bottom
flask equipped with a thermowell, reflux condenser, and septum. The apparatus is evacuated with stirring and raised in temperature to 100 °C. The solution is allowed to off-gas acetic acid under reduced
pressure for approximately 12 h at 100 °C to generate the ln(MA)3 solution. Then, the flask is filled with nitrogen, and a 20 ml_
portion of dry toluene is added. b) Synthesis of InP MA MSCs from ln(MA)3 Solution and
P(SiMe3)3.
In a nitrogen filled glovebox, 465 pi of P(SiMe3)3 is added to 10 mL of toluene, drawn into a syringe and sealed with a rubber stopper. The ln(MA)3 flask is brought up to 110 °C and the P(SiMe3)3 solution is injected. The formation of MSCs is monitored via UV-vis of timed aliquots taken from the reaction solution until the MSCs had fully formed as indicated by no further changes in the UV-vis spectra. The MSCs are then precipitated from the solution by the addition of acetonitrile (until turbidity is observed) and centrifugation. The precipitate is then dissolved in toluene and again precipitated by the addition of acetonitrile (until turbidity is observed) followed by centrifugation. This is repeated 3 times.
Working Example 2: InP QDs synthesis with MSCs addition at 200°C & growth at 265 °C (IPMAQD081)
In a four-neck round-bottom flask equipped with a reflux condenser, 12 ml of distilled squalane is evacuated with stirring and then heated to 375°C under argon. 2 ml of 6.3-1 O 4 M MSCs solution in squalane are injected to the flask. After 60 seconds the mantle is removed and the flask is cooled to 200°C. The mantle is then brought back and the flaks is heated to 265°C. 0.6-1 .1 ml of 3.4- 1 O 4 M MSCs solution in squalane is added to the flask at 31 min, 37min, 43min,49min, 53min, 60min, 64min at a rate of 0.7 ml/min. At 69min and 77min, a solution of 6.3- 104 M MSCs in squalene is added to the flask. After 78 minutes the mantle is removed and the flask is cooled to room temperature. Table 1 shows the results.
Table 1
Figure imgf000061_0002
Working Example 3: InP QDs synthesis with MSCs addition at 180 °C, growth between 200- 300 °C (IPMAQD080)
In a four-neck round-bottom flask equipped with a reflux condenser, 12 ml of distilled squalane is evacuated with stirring and then heated to 375°C under argon. 2 ml of 3.15- 1 O 4 M MSCs solution in squalane from working example 1 are injected to the flask. After 140 seconds the mantle is removed and the flask is cooled down. The mantle is then brought back and the flaks is heated to 180°C. 1 ml of 6.3-1 O 4 M MSCs solution in squalane is added to the flask at a rate of 0.5 ml/sec. The flask is heated to 300°C. After 20 minutes the mantle is removed and the flask is cooled to room temperature. Table 2 shows the results.
Table 2
Added MSCs (mol) Exciton (nm) Max/M in
Figure imgf000061_0001
Figure imgf000062_0001
Working Example 4: InP QDs synthesis with MSCs addition at 70°C,
^ growth between 200- 250°C (IPMAQD057)
In a four-neck round-bottom flask equipped with a reflux condenser, 2.5 ml of distilled squalane are evacuated with stirring and then heated to 375°C under argon. 1 ml of 6.3-1 O 6 M MSCs solution in squalane from working example 1 are injected to the flask. After 30 seconds the mantle is removed 1 n
w and the flask is cooled down. The mantle is then brought back and the flaks is heated to 70°C. 0.2 ml of 6.3-1 O 6 M MSCs solution in squalane is added to the flask at a rate of 0.2 ml/sec. The flask is heated to 250 C. After 25 minutes the mantle is removed and the flask is cooled to room temperature.
Table 3 shows the results.
15
Table 3
Figure imgf000062_0002
20
Working Example 5: Core synthesis:
Cluster Synthesis
The MSCs are synthesized as described in the literature7 D. Gary et al., Chem. Mater., 2015, 1432.
25
QD Synthesis
Synthesis of InP Cores having an exciton wavelength of 552nm
6 ml of distilled squalane is put in glove box into a 50ml_, 14/20, four-neck round-bottom flask equipped with a reflux condenser, septums and a tap between the flask and the condenser. The apparatus is evacuated with stirring and heated to 90 °C. After that the flask is filled with argon and heated to 375°C (with scarf). A 3.15x1 O 4 M solution of MSCs in squalane is prepared. 1 ml of a 3.15x1 O 4 M solution of MSCs in squalane is injected to the flask at 375°C. After 110 seconds the mantle is removed and the flask is cooled down with fan. Resulting in a sample with an exciton wavelength of 552nm and a max/min of 1.32.
Working Example 6: Core synthesis:
Synthesis of InP Cores having an exciton wavelength of 598 nm
A 50ml_, 14/20, four-neck round-bottom flask equipped with a reflux condenser is evacuated, and 12 ml of distilled squalane is injected into it. The apparatus is evacuated with stirring (and heated to 375°C under argon. Two solutions are prepared from the cleaned clusters solution:
Injection solutions ml solution of the MSCs in distilled squalene is prepared, with a concentration of 6.3E-4M.
Addition solution: 5.6 ml solution of the MSCs in distilled squalane is prepared, with a concentration of 3.36E-4M.
2ml of the injection solution are injected to the flask at 375°C.
After 1 minute the mantle is removed and the flask is cooled to 200C. The flask is then returned into the mantle and the flask is heated to 265C.
At this point more MSCs are added, using the additions solution. The additions are done at a rate of 0.7ml/min at the given times (minutes after the initial injection):
31 - 0.6ml
37 - 0.6ml
43 - 0.8ml
49 - 0.8ml
53 - 1.1 ml
60 - 0.6ml
64 - 0.6ml 69 - 0.2ml from the injection solution
77 - 0.3ml from the injection solution, at a rate of ~2ml/min
After 78 minutes the mantle is removed and the flask is cooled to RT. Results:
InP QDs are formed with exciton at 598nm and max/min of 1.49.
Working Example 7: Core synthesis:
Synthesis of InP cores having an exciton wavelength of 593 nm
A 50ml_, 14/20, four-neck round-bottom flask equipped with a reflux condenser is evacuated, and 10 ml of distilled squalane is injected into it. The apparatus is evacuated with stirring (pressure is lowered from 300mtorr to200 mTorr during 1 hour) and heated to 375°C under argon. In a glove box a solution of MSCs with a concentration of 3.15x1004M is prepared in distilled squalene. 4 ml (1.26E-06 moles) of this solution is injected to the flask at 375°C, using a 16 gauge needle and 6 ml syringe;
after 4 minutes the mantle is removed and the flask is cooled to 200°C by blowing air with a fan. The mantle is then brought back and the flask is heated to 265°C.
At this point more MSCs is added, using the same solution that is initially injected; 20 gauge needle and 3ml syringe are used, the addition is done at a rate of 0.7ml/min at the given times (compared to the initial injection): Minute 15 - 0.6 ml (1.89E-07 mol)
Minute 25 - 0.7 ml (2.21 E-07 mol)
Minute 32 - 0.7 ml
After 34 minutes the mantle is removed and the flask is cooled to RT, the material is stored in GB overnight, and the day after is transferred in the glove box to a new flask, heated under argon to 265°C and another 0.6 ml of the same MSCs solution is added, then cooled down to RT. Results:
InP QDs are formed with exciton at 593nm and max/min of 1.3. Working Example 8: ZnSe shell synthesis on InP cores having exciton CWL of 552 nm.
In this synthesis the InP cores had an exciton with a CWL of 552 nm and max/min exciton peak optical density ratio of 1.32. The final solution is cleaned with a mixture of anhydrous toluene and ethanol (ratio
crude:toluene:ethanol: 1 :2:8). The process is repeated with ratio
crude:toluene:ethanol: 1 :2:6. The cleaned cores are re-dissolved in 2.5mL of oleylamine(OLAm). This solution will be called further“SSP InP cores”. 75mg of Zn(CI)2 and 1 amount (0.28mL of 2M TOP:Se) of anion shell precursor are added to SSP InP cores. The solution is heated by steps to 220C, followed by one injection of cation (1.1 mL of 0.4M Zn(acetate)-0.8M oleylamine in ODE) shell precursor. Afterwards, the solution is heated to 240C, followed by one injection of anion (0.19mL of 2M TOP:Se) shell precursor.
Afterwards, the solution is heated to 280C, followed by one injection of cation (1.1 mL of 0.4M Zn(acetate)-0.8M oleylamine in ODE) shell precursor. Afterwards the solution is heated to 320C, followed by one injection of anion (0.19mL of 2M TOP:Se) shell precursor, and later an additional injection of cation (1.1 mL of 0.4M Zn(acetate)-0.8M oleylamine in ODE) shell precursor. Table 4 shows the anion / cation precursor injections.
Table 4
Figure imgf000065_0001
Injection Zn(ac) TOP:Se Zn(ac) TOP:Se Zn(ac) end
Figure imgf000066_0001
Figurel presents the results of shell coating. Working Example 9: ZnSe shell synthesis on InP cores having exciton CWL of 598 nm.
This example differs from example 8 since by the exciton CWL and max/min exciton peak optical density ratio of the InP core, which are 598 nm and 1.3 in example 9 as opposed to 552 nm and 1.32 in example 8. The shell synthesis steps are identical to example 8.
Figure2 presents the results of shell coating.
Working Example 10: ZnSe shell synthesis on InP cores having exciton CWL of 593 nm.
This example differs from example 8 since by the exciton CWL and max/min exciton peak optical density ratio of the InP core, which are 593 nm and 1.3 in example 10 as opposed to 552 nm and 1.32 in example 8. The shell synthesis steps are identical to example 8.
Table 5 lists the values of QY, FWHM and trap emission for both examples described.
Table 5
Figure imgf000066_0002
Working Example 11 : measurements of core/shell volume ratios Core/shell volume ratios of samples from example 8 and 10
The higher the ratio, the thicker the shell is relative to the core.
The Zn and In atomic ratios are measured using EDS in HRTEM, using STEM mode. Table 6 shows the results.
Table 6
Figure imgf000067_0001
The calculation is based on the following formula
Mw(ZnSe)
Vshell _ Zn p(ZnSe)
Vcore In Mw(InP)
pifnP)
Working Example 12: Formation of InP QDs
In a nitrogen filled glove-box, 120 ml of squalane (batch SQLVAC2) is transferred into a 500 ml_, 24/40, four-neck round-bottom flask equipped with a stop-cock tap. (The squalane used is previously put under reduced pressure 200 mTorr at a temperature of 90C for 2hrs.) The flask + tap are connected to a reflux condenser and the apparatus is evacuated with stirring at 90 °C (pressure is 100 mTorr) and heated to 375 °C. Two solutions are prepared from a cleaned clusters solution. The crude cluster solution is cleaned by 5 successive precipitation cycles using toluene, acetonitrile and centrifugation.
Injection solution:
13.06 ml of the MSCs solution with a 92.5 mg/ml of inorganic content in squalane are mixed with a further amount of 9.94 ml of squalane. Additions solution:
7.57 ml of the MSCs solution with a 92.5 mg/ml of inorganic content in squalane are mixed with a further 32.43 ml of squalane. 20 ml of the injection solution are injected to the flask at 375°C. This is done by simultaneous injection of four 5 ml portions of the solution, using 14 & 12 gauge needles and 6 ml syringes;
after 1 minute the mantle is removed and the flask is cooled to 200°C using an air gun. The mantle is then brought back and the flask is heated to 265°C.
At this point more MSCs are added, using the additions solution; 14 gauge needle and 50 ml syringe are used; the additions are done at a rate of 7.5ml/min (12.2% of the initial injected number of MSCs in each addition) at the given times (minutes after the initial injection):
21 , 25, 29, 33, and 37.5.
After 41.5 minutes the mantle is removed and the flask is cooled to RT.
Figure 3 shows the temperature profile for the reaction (recorded directly from the controller).
Results:
2.90E-05 moles of InP QDs are formed with exciton at 579 nm and max/min of 1.49 (measurement of cooled crude in toluene anhydrous).
ZnSe shell synthesis on InP cores having exciton CWL of 579 nm.
In this synthesis the InP cores had an exciton with a CWL of 579 nm and max/min exciton peak optical density ratio of 1.49 The final solution is cleaned with a mixture of anhydrous toluene and ethanol (ratio
crude:toluene:ethanol: 1 :2:8). The process is repeated with ratio crude:toluene:ethanol: 1 :2:6. The cleaned cores are re-dissolved in 2.5ml_ of oleylamine(OLAm). This solution will be called further“SSP InP cores”.
85mg of Zn(CI)2 are added to SSP InP dissolved in 4.8 ml oleylamine. The flask is put under vacuum on the schenk line for 30min. Then heated quickly to 250°C under argon and remain for 30 min at this temperature. Then the flask is cooled down to 180°C (without removing the mantle, just put setpoint at 180°C) where 2.6ml_ of Zn(CI)2 in oleylamine is added, followed by injection of 0.72ml_ 2M TOP:Se . The temperature is gradually increased to 320°C, where 3.1 ml of 0.4 ZnSt2 in oleylamine are added to the flask. The reaction proceeded for 3 hours in this temperature, then cooled down and stored under Argon.
Final results - CWL= 632 nm, FWHM=38.5 nm
Working Example 13:
Fabrication of solution processed ELQ-LED devices
The production of solution-based OLEDs has already been described many times in the literature, for example in WO 2004/037887 and WO
2010/097155. The process is adapted to the circumstances described below (layer-thickness variation, materials).
The inventive material combinations are used in the following layer sequence:
- substrate,
- ITO (50 nm),
- Buffer (20 nm),
- hole transport layer (20 nm),
- emission layer (EML) (30 nm),
- electron-transport layer (ETL) (50 nm),
- electron injection layer (EIL) (3 nm),
- cathode (Al) (100 nm). Glass plates coated with structured ITO (indium tin oxide) in a thickness of 50 nm serve as substrate. These are coated with the buffer (PEDOT) Clevios P VP Al 4083 (Heraeus Clevios GmbH, Leverkusen). The spin coating of the buffer is carried out from water in air. The layer is
subsequently dried by heating at 180°C for 10 minutes. The hole transport layers and the emission layers are applied to the glass plates coated in this way.
The hole-transport layer is the polymer of the structure shown in table 7, which is synthesised according to WO2010/097155. The polymer is dis- solved in toluene, so that the solution typically has a solid content of approx. 5 g/l if, as here, the layer thickness of 20 nm which is typical for a device is to be achieved by means of spin coating. The layers are applied by spin coating in an inert-gas atmosphere, in the present case argon, and dried by heating at 220°C for 30 min. The emission layer is composed of one of the materials according to the present invention for each single ELQ-LED device. The materials used in this example E1 to E5 are disclosed in table 8.
The emissive layer material is dissolved in toluene. The solids content of such solutions is about 30 mg/ml if, as here, the layer thickness of 30nm which is typical for a device is to be achieved by means of spin coating. The layers are applied by spin coating in an inert-gas atmosphere, and dried by heating at 120°C for 10 minutes.
Table 7 shows the structural formulae of the materials used for the ELQ- LEDs devices
Table 7
Figure imgf000070_0001
Figure imgf000071_0002
The materials for the electron-transport layer and the electron injection layer are likewise applied by thermal vapour deposition in a vacuum chamber and are shown as well in table 7. The electron-transport layer consists of the material ETM and the electron injection layer consists of LiQ. The cathode is formed by the thermal evaporation of an aluminium layer with a thickness of 100 nm.
The ELQ-LEDs are characterised by standard methods. For this purpose, the current/voltage/luminance characteristic lines (IUL characteristic lines) and the electroluminescence (EL) spectra are recorded. The EL spectra are taken at a luminous density of 10cd/m2 and the CIE 1931 x and y coordinates are then calculated from the EL spectrum. The device data of various ELQ-LEDs is summarized in Table 8 and Fig. 4 shows the EL spectrum of the ELQ-LED devices fabricated in this working example.
Table 8
Figure imgf000071_0001
Workinq Example 14: InP Core Synthesis
1. Magic Size Crystal (MSC) Preparation Indium acetate (4.65 g) and myristic acid (13.25 g) are combined in a 500 ml_ 4 necked round bottom flask. The flask is vacuumed at 100 °C for 3.5 hours at 120 mTorr to produce indium myristate. Then, under Argon gas, anhydrous toluene (100 ml_) is injected into the flask, and the temperature is raised to 110 °C. Next, a solution of PTMS in toluene (2325 pl_/ 50 ml_) is injected into the flask. Additional injections of PTMS solutions in toluene (0.1 v/v) are then performed at the following times and volumes (minutes from initial injection/volume): 12 min/2 ml_, 16 min/2 ml_, 29 min/1.5 ml_. At 37 minutes, the flask is cooled to room temperature.
Purification of MSCs: The reaction contents are centrifuged at 2700G for 7 minutes to isolate the supernatant (SN). Acetonitrile (ACN, 80 ml_) is then added to the SN, which is centrifuged to isolate the percipirate (PPT). The PPT is then subject to several rounds of solvent/antisolvent centrifuge precipitation using toluene and ACN. Finally, the PPT is dispersed in squalane to a concentration of 1.39 x106 mol MSC/mL squalane.
2. InP QD Synthesis
Distilled squalane (60 ml_) is vacuumed for 1 hour at 200 mTorr in a 250 ml_ four necked round bottom flask. Then, under Argon gas, the flask is heated to 375 °C. Squalane (1.12 ml_) is added to part of the MSC solution described above (10.9 ml_), and 10 ml_ of the new solution is injected into the flask. After 1 min the reaction flask is cooled to 200 °C. Then the flask is re-heated to 265 °C and additional injections of solutions of MSCs in squalane (1.22 ml_, prepared by combining 10 ml_ MSC solution with 23 ml_ squalane) are made at the following times (minutes from initial injection): 20.5, 24, 28, 32, 36, 40. At 44 min, 1.9 ml_ is injected. At 48 min, the reaction flask is cooled to room temperature. Purification of InP QDs: solvent/antisolvent centrifuge precipitation is performed using the 1 :2:4 volume ratio of crude reaction product: toluene: ethanol. A second cycle of 2:3 toluene:ethanol is performed. Reference Example 1 : Synthesis of InP/ZnSe (Se/S=°°)
InP QDs (2.7 x107 mol), prepared according to InP Core Synthesis described above, are dispersed in oleylamine (3.7 ml_) and transferred into a 50 mL four necked round bottom flask inside a Nitrogen glove box. ZnCh (0.065 g) is added to the flask. The flask is vacuumed on the Schlenk line below 150 mTorr at 35 °C for 30 min. Then, under Argon, the flask is heated at 250 °C for 3 min. The flask is cooled to 180 °C. Then, ZnCh in oleylamine (2 mL, 0.55M, pre-complexed by vacuuming for 1 hour at 120 °C) and TOP:Se (0.55 mL, 2M) are injected into the flask. 30 minutes after the injection, the temperature is raised to 200 °C and maintained for 30 minutes. Then the temperature is raised to 320 °C, and Zinc stearate in oleylamine (2.4 mL, 0.4 M, pre-complexed by vacuuming for 1 hour at 100 °C) is injected dropwise over 10 min into the flask. After 3 hours at 320 °C, the flask is cooled to room temperature.
QY of the crude reaction product is measured in toluene using the
Hamamatsu Quantaurus absolute PL quantum yield spectrometer (model d 1347-11 ).
Surface treatment: Crude reaction product (3-4 mL) is washed by 1 :1 :2 crude: toluene :ethanol centrifuge precipitation, with a second cleaning cycle of the PPT using 1 :2 toluene: ethanol. The PPT is then dispersed in 3-4 mL hexane and centrifuged to isolate the SN from any other PPTs.
Finally, the hexane is evaporated and the final PPT containing lnP/ZnSexSi- x nanoparticles is dispersed in toluene at 20 mg inorganic QDs/mL. 10mg Zinc acetate is added. The mixture is sonicated for 5 minutes and stirred for 1 hour. Afterwards, the mixture is illuminated with 450 nm light (peak wavelength of 455 nm) at 300 mW/cm2for upto16 hours. Post surface treatment QY is measured on the Hamamatsu in toluene (measured solutions have absorption of 60-70% in Hamamatsu). Reference Example 2: Synthesis of lnP/ZnSexSi-x
Figure imgf000074_0001
Synthesis is carried out as in Reference Example 1 , except for the following differences: 1 ) 0.425 ml_ of TOP:Se (2M) are used. 2) 10 minutes after the injection of zinc stearate in oleylamine, TOP:S (0.125 ml_, 2.24 M) is injected into the flask. The reaction is held at 320 °C for 3 hours before cooling to room temperature. Crude QY measurement, surface treatment, and post surface treatment QY measurement are carried out as in
Comparative Example 1.
Working Example 15: Synthesis of lnP/ZnSexSi-x (Se/S=2)
Synthesis is carried out as in Reference Example 1 , except for the following differences: 1 ) All precursor quantities are multiplied by 1.3. 2) 0.47 ml_ of TOP:Se (2M) are used. 3) 10 minutes after the injection of zinc stearate in oleylamine, TOP:S (0.22 ml_, 2.24 M) is injected into the flask. The reaction is held at 320 °C for 3 hours before cooling to room temperature. Crude QY measurement, surface treatment, and post surface treatment QY
measurement are carried out as in Comparative Example 1. Working Example 16: Synthesis of lnP/ZnSexSi.x (Se/S=1.5)
Synthesis is carried out as in Reference Example 1 , except for the following differences: 1 ) All precursor quantities are multiplied by 1.3. 2) 0.43 ml_ of TOP:Se (2M) are used. 3) 10 minutes after the injection of zinc stearate in oleylamine, TOP:S (0.26 ml_, 2.24 M) is injected into the flask. The reaction is held at 320 °C for 3 hours before cooling to room temperature. Crude QY measurement, surface treatment, and post surface treatment QY
measurement are carried out as in Comparative Example 1.
Working Example 17: Synthesis of lnP/ZnSexSi.x (Se/S=1)
Synthesis is carried out as in Reference Example 1 , except for the following differences: 1 ) 0.275 ml_ of TOP:Se (2M) are used. 2) 10 minutes after the injection of zinc stearate in oleylamine, TOP:S (0.25 ml_, 2.24 M) is injected into the flask. The reaction is held at 320 °C for 3 hours before cooling to room temperature. Crude QY measurement, surface treatment, and post surface treatment QY measurement are carried out as in Comparative Example 1.
Working Example 18: Synthesis of lnP/ZnSexSi-x (Se/S=2) by use of dodecanethiol
InP QDs (3.5 x107 mol), prepared according to InP Core Synthesis described above, are dispersed in oleylamine (4.8 ml_) and transferred into a 50 mL four necked round bottom flask inside a Nitrogen glove box. ZnCh (0.085 g) is added to the flask. The flask is vacuumed on the Schlenk line below 150 mTorr at 35 °C for 30 min. Then, under Argon, the flask is heated at 250 °C for 3 min. The flask is cooled to 180 °C. Then, ZnCh in oleylamine (2.6 mL, 0.55M, pre-complexed by vacuuming for 1 hour at 120 °C) and TOP:Se (0.48 mL, 2M) are injected into the flask. 30 minutes after the injection, the temperature is raised to 200 °C and maintained for 30 minutes. Then the temperature is raised to 320 °C, and Zinc stearate in oleylamine (2.4 mL, 0.4 M, pre-complexed by vacuuming for 1 hour at 100 °C) is injected dropwise over 10 min into the flask. 10 minutes after the injection of zinc stearate in oleylamine, dodecanethiol (0.12 mL, degassed by 30 min argon bubbling) is injected into the flask. After 2 hours at 320 °C, the flask is cooled to room temperature. Crude QY measurement, surface treatment, and post surface treatment QY measurement are carried out as in Reference Example 1
Reference Example 3: Synthesis of lnP/ZnSexSi.x (Se/S=0.5)
Synthesis is carried out as in Reference Example 1 , except for the following differences: 1 ) All precursor quantities are multiplied by 1.3. 2) 0.24 mL of TOP:Se (2M) are used. 3) 10 minutes after the injection of zinc stearate in oleylamine, TOP:S (0.43 mL, 2.24 M) is injected into the flask. The reaction is held at 320 °C for 3 hours before cooling to room temperature. Crude QY measurement, surface treatment, and post surface treatment QY measurement are carried out as in Reference Example 1.
Reference Example 4: Synthesis of lnP/ZnSexSi-x (Se/S=0.33)
Synthesis is carried out as in Reference Example 1 , except for the following differences: 1 ) All precursor quantities are multiplied by 1.3. 2) 0.18 ml_ of TOP:Se (2M) are used. 3) 10 minutes after the injection of zinc stearate in oleylamine, TOP:S (0.49 ml_, 2.24 M) is injected into the flask. The reaction is held at 320 °C for 3 hours before cooling to room temperature. Crude QY measurement, surface treatment, and post surface treatment QY
measurement are carried out as in Reference Example 1.
Comparative Example 1 : Synthesis of lnP/ZnSexSi-x (Se/S=0)
Synthesis is carried out as in Reference Example 1 , except for the following differences: 1 ) 0.5 ml_ of TOP:S (2.24M) are used instead of TOP:Se at 180 °C. The reaction is held at 320 °C for 3 hours before cooling to room temperature. Crude QY measurement, surface treatment, and post surface treatment QY measurement are carried out as in Reference Example 1. Table 9 shows the results of the measurements.
Table 9
Figure imgf000076_0001
Figure imgf000077_0001
Table 9 shows that in the Working examples, which have a Se/S ratio range of 1 -2, QY of over 75% is achieved while SA remains below 0.315 after surface treatment with Zn-acetate and illumination. These examples show a percent increase of QY of over 40%, giving final QY values of > 75% after surface treatment. In contrast, the Comparative examples which have Se:S ratios below 1 or above 2 show lower percent increases of QY after surface treatment with Zn-acetate and illumination. Therefore, we identify the Se:S ratio range of 1 -2 in conjunction with surface treatment as an optimal range which a) significantly increases the QY by S incorporation, b) does not overdo S incorporation, which would increase the lattice strain and lower QY, and c) maintains a low SA (compare to SA of 0.353 in Comparative example 5 in the case of S only).
Working Example 19: Procedure for elemental analysis by EDS
The product is cleaned from the organic ligands in toluene/ethanol mixtures. Cleaned product is dissolved in analytical toluene and a concentrated solution is dripped on a Si chip. For the TEM the solution is diluted and one droplet of the diluted solution is dripped on a Cu/C TEM grid with ultrathin amorphous carbon layer. The Si chip/grid is dried in vacuum of ~8x10-2 torr at 90oC for 1 5hrs to remove the residues of the solvent as well as possible organic residues.
SEM EDS is carried out on FEI sirion machine equipped with Oxford detector and INCA software. Accelerating voltage of 25kV is used.

Claims

Patent Claims
1 . A semiconducting light emitting nanoparticle comprising at least a first semiconducting material comprising at least a 1 st element of group 13 elements of the periodic table and a 2nd element of the group 15 elements of the periodic table, and at least one shell layer comprising at least a 3rd element of the group 12 elements of the periodic table and a 4th element of the group 16 elements of the periodic table, wherein the nanoparticle has the self-absorption value 0.35 or less, preferably it is in the range from 0.30 to 0.01 , more preferably from 0.25 to 0.05, even more preferably from 0.23 to 0.12, and the Full Width at Half Maximum 46 nm or less, preferably it is in the range from 46 nm to 20 nm, more preferably from 40 nm to 25 nm, even more preferably from 38 nm to 30 nm.
2.The nanoparticle according to claim 1 , wherein the nanoparticle has the trap emission 15 % or less, preferably 10% or less, more preferably it is in the range from 8% to 5%.
3.The nanoparticle according to claim 1 or 2, wherein the nanoparticle emits light having the peak maximum light emission wavelength in the range from 520nm to 700nm, preferably from 550nm to 650nm, more preferably from 580nm to 650nm.
4.The nanoparticle according to any one of claims 1 to 3, wherein the average size of the first semiconducting material is in the range from 1 to 4 nm, preferably it is in the range from 2.5 to 4.0, more preferably from 2.7 to 3.6.
5.The nanoparticle according to any one of claims 1 to 4, wherein the size distribution of the first semiconducting material is 10% or less, preferably it is in the range from 10% to 3%, more preferably from 8% to 4%.
6.The nanoparticle according to any one of claims 1 to 5, where the volume ratio between the shell layer and the first semiconducting material is 5 or more, preferably it is in the range from 5 to 40, more preferably it is from 10 to 30.
7. A semiconducting light emitting nanoparticle comprising at least a first semiconducting material comprising at least a 1st element of group 13 elements of the periodic table and a 2nd element of the group 15 elements of the periodic table, and at least one shell layer comprising at least a 3rd element of the group 12 elements of the periodic table and a 4th element of the group 16 elements of the periodic table, wherein the size distribution of the first semiconducting material is 10% or less, preferably in the range from 10% to 3%, more preferably from 8% to 4%, and the volume ratio between the shell layer and the first semiconducting material is 5 or more, preferably it is in the range from 5 to 40, more preferably it is from 10 to 30.
8.The nanoparticle according to any one of claims 1 to 7, wherein the shell layer is represented by following formula (II),
MSei-zSz (II) wherein M is Zn2+, or Cd2+, preferably M is Zn2+; 0£z<1 , preferably 0<z<1.
9.The nanoparticle according to any one of claims 1 to 8, wherein the ratio of Se and S elements in the shell layer is in the range from 0.6 to 4.0, preferably it is in the range from 0.7 to 3.0, more preferably it is in the range from 0.8 to 2.5, even more preferably from 1.0 to 2.0.
10. A semiconducting light emitting nanoparticle comprising at least a first semiconducting material comprising at least a 1st element of group 13 elements of the periodic table and a 2nd element of the group 15 elements of the periodic table, and at least one shell layer, wherein the shell layer is represented by following formula (II),
MSei-zSz (II) wherein M is Zn2+, or Cd2+, preferably M is Zn2+; 0<z<1 , and the ratio of Se and S elements in the shell layer is in the range from 0.6 to 4.0, preferably it is in the range from 0.7 to 3.0, more preferably it is in the range from 0.8 to 2.5, even more preferably from 1.0 to 2.0.
11. The nanoparticle according to any one of claims 1 to 10, wherein the concentration of Se in the shell layer varies from a high concentration of the first semiconducting material side in the shell layer to a low concentration of the opposite side in the shell layer, more preferably, the concentration of S in the shell layer varies from a low concentration of first semiconducting material side of the shell layer to a higher concentration to the opposite side of the shell layer.
12. A process for synthesizing a semiconducting nanoparticle comprising following steps (a) to (h),
(a) mixing a semiconductor nanosized cluster and an another compound or to an another mixture of compounds at a temperature in the range from 260 to 500°C in order to get a reaction mixture, preferably said temperature is in the range from 300 to 460°C, more preferably from 330 to 430°C, even more preferably from 360 to 400°C, preferably the said another compound is a solvent;
(b) cooling the reaction mixture to slow down or stop the growth of a first semiconducting material in step (a);
(c) adjusting or keeping the temperature of the reaction mixture from step (b) in the range from 40 °C to 300 °C, preferably in the range from 50 °C to
290 °C, more preferably from 60 °C to 280 °C, furthermore preferably from 65 °C to 270°C to allow a growth of a first semiconducting material in the mixture; (d) adding a semiconductor nanosized cluster to the reaction mixture;
(e) adjusting or keeping the temperature of the reaction mixture from step
(d) in the range from 40 °C to 300 °C, preferably in the range from 50 °C to 290 °C, more preferably it is from 60 °C to 280 °C, furthermore preferably from 65 °C to 270°C to allow a growth of a first semiconducting material in the mixture;
(f) optionally repeating steps (d) and (e); (g) adjusting or keeping the temperature of the reaction mixture from step
(e) or (f) in the range from 200 °C to 350 °C, preferably in the range from 230 °C to 320 °C, more preferably it is from 240°C to 310 °C, furthermore preferably from 250°C to 300°C to allow growth of a first semiconducting material in the mixture;
(h) cooling the reaction mixture to stop the growth of first semiconducting material in step (e) or step (f).
13. The process according to claim 12, wherein said another compound is a solvent having the boiling point 250 °C or more, preferably in the range from 250 °C to 500 °C, more preferably in the range from 300 °C to 480 °C, even more preferably from 350 °C to 450 °C, furthermore preferably it is from 370°C to 430 °C.
14.The process of claim 12 or 13, wherein said another compound is a solvent selected from one or more members of the group consisting of squalenes, squalanes, heptadecanes, octadecanes, octadecenes, nonadecanes, icosanes, henicosanes, docosanes, tricosanes,
pentacosanes, hexacosanes, octacosanes, nonacosanes, triacontanes, hentriacontanes, dotriacontanes, tritriacontanes, tetratriacontanes, pentatriacontanes, hexatriacontanes, oleylamines, and trioctylamines, with preferably being of squalene, squalane, heptadecane, octadecane, octadecene, nonadecane, icosane, henicosane, docosane, tricosane, pentacosane, hexacosane, octacosane, nonacosane, triacontane, hentriacontane, dotriacontane, tritriacontane, tetratriacontane,
pentatriacontane, hexatriacontane, oleylamine, and trioctylamine, more preferably squalane, pentacosane, hexacosane, octacosane, nonacosane, or triacontane, even more preferably squalane, pentacosane, or
hexacosane.
15. The process according to any one of claims 12 to 14, wherein the temperature of the reaction mixture in step (a) is kept in the temperature range for from 1 second to 10 minutes, preferably from 5 seconds to 5 minutes, more preferably from 10 seconds to 200 seconds, more preferably from 20 seconds to 160 seconds.
16. The process according to any one of claims 12 to 15, wherein the total amount of the inorganic part of said lll-V semiconductor nanosized clusters in step (a) is in the range from 0.1x1 O 4 to 1x1 O 3 mol%, preferably being of the amount in the range from 0.5x1 O 4 to 5x1 O 4 mol%, more preferably from 1 x1 O 4 to 3x1 O 4 mol% of the reaction mixture.
17.The process according to any one of claims 12 to 16, wherein the cooling rate in step (b) is in the range from 0.05°C/s to 50°C/s, preferably it is from 0.1 °C/s to 10°C/s, more preferably it is from 0.2°C/s to 5°C/s, even more preferably it is from 0.5°C/s to 2°C/s.
18. The process according to any one of claims 12 to 17, wherein the cooling rate in step (h) is in the range from 0.01 °C/s to 10°C/s, preferably it is from 0.05°C/s to 5°C/s, more preferably it is from 0.1 °C/s to 1 °C/s, even more preferably it is from 0.2°C/s to 0.7°C/s.
19. A process for synthesizing a semiconducting light emitting nanoparticle comprising following steps (i) and (j),
(i) mixing a first semiconducting material, preferably it is obtained in the step (h) according to any one of claims 12 to 18, and at least a first cation shell precursor and a first anion shell precursor, optionally in a solvent, to form a shell layer onto the first semiconducting material,
(j) quenching a shell formation of step (d), wherein said first cation shell precursor is a salt of an element of the group 12 of the periodic table and the first anion shell precursor is a source of an element of the group 16 of the periodic table, more preferably said first cation shell precursor is selected from one or more member s of the group consisting of Zn-stearate, Zn-myristate, Zn-oleate, Zn-laurate, Zn-palmitate, Zn-acetylacetonate, Cd-stearate, Cd-myristate, Cd-oleate, Cd-laurate, Cd- palmitate, Cd-acetylacetonate a metal halogen represented by chemical formula (III) and a metal carboxylate represented by chemical formula (IV),
MX2n (III) wherein M is Zn2+, or Cd2+, preferably M is Zn2+, X2 is a halogen selected from the group consisting of Cl , Br and I , n is 2,
[M(02CR1) (02CR2)] - (IV) wherein M is Zn2+, or Cd2+, preferably M is Zn2+;
R1 is a linear alkyl group having 1 to 30 carbon atoms, a branched alkyl group having 4 to 30 carbon atoms, a linear alkenyl group having 2 to 30 carbon atoms, or a branched alkenyl group having 4 to 30 carbon atoms, preferably R1 is a linear alkyl group having 1 to 30 carbon atoms, or a linear alkenyl group having 2 to 30 carbon atoms, more preferably, R1 is a linear alkyl group having 5 to 25 carbon atoms, or a linear alkenyl group having 6 to 25 carbon atoms, even more preferably R1 is a linear alkyl group having 10 to 20 carbon atoms, or a linear alkenyl group having 10 to 20 carbon atoms, furthermore preferably R1 is a linear alkenyl group having 10 to 20 carbon atoms,
R2 is a linear alkyl group having 1 to 30 carbon atoms, a branched alkyl group having 4 to 30 carbon atoms, a linear alkenyl group having 2 to 30 carbon atoms, or a branched alkenyl group having 4 to 30 carbon atoms, preferably R2 is a linear alkyl group having 1 to 30 carbon atoms, or a linear alkenyl group having 2 to 30 carbon atoms, more preferably R2 is a linear alkyl group having 5 to 25 carbon atoms, or a linear alkenyl group having 6 to 25 carbon atoms, even more preferably R2 is a linear alkyl group having 10 to 20 carbon atoms, or a linear alkenyl group having 10 to 20 carbon atoms, furthermore preferably R2 is a linear alkenyl group having 10 to 20 carbon atoms, and preferably said anion shell precursor is selected from one or more members of the group consisting of Trioctylphosphine : Se,
Tributylphosphine : Se, Trioctylphosphine : S, Tributylphosphine : S, and thiols.
20. The process according to claim 19, wherein the molar ratio of total shell precursors used in step (i) and total first semiconducting material used in step (i) is 6 or more, preferably in the range from 7 to 30, more preferably from 8 to 30, even more preferably from 9 to 27.
21.The process according to claim 19 or 20, wherein at least said first anion shell precursor and a second anion shell precursor are added sequentially in step (i).
22. The process according to any one of claims 19 to 21 , wherein said first anion shell precursor is Trioctylphosphine : Se, or Tributylphosphine : Se, and the second anion shell precursor is Trioctylphosphine : S,
Tributylphosphine : S, or a thiol.
23. A semiconducting material obtainable or obtained from the process according to any one of claims 12 to 18.
24. A semiconducting light emitting nanoparticle obtainable or obtained from the process according to any one of claims 19 to 22.
25. A composition comprising at least one semiconducting light emitting nanoparticle according to any one of claims 1 to 11 , 24, or at least one semiconducting material of claim 23, and at least one additional material, preferably the additional material is selected from the group consisting of organic light emitting materials, inorganic light emitting materials, charge transporting materials, scattering particles, host materials, nanosized plasmonic particles, photo initiators, and matrix materials.
26. Formulation comprising at least one semiconducting light emitting nanoparticle according to any one of claims 1 to 11 , 24, or at least one semiconducting material of claim 23, or a composition according to claim 25, and at least one solvent, preferably the solvent is selected from one or more members of the group consisting of aromatic, halogenated and aliphatic hydrocarbon solvents, more preferably selected from one or more members of the group consisting of toluene, xylene, ethers,
tetrahydrofuran, chloroform, dichloromethane and heptane, purified water, ester acetates, alcohols, sulfoxides, formamides, nitrides, ketones.
27. Use of the semiconducting light emitting nanoparticle according to any one of claims 1 to 11 , 24, or at least one semiconducting material of claim 23, or a composition according to claim 25, or the formulation according to claim 26 in an electronic device, optical device or in a biomedical device.
28. An optical medium comprising at least one semiconducting light emitting nanoparticle according to any one of claims 1 to 11 , 24, or at least one semiconducting material of claim 23, or a composition according to claim 25.
29. An optical device comprising at least said optical medium of claim 28.
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