WO2019215059A1

WO2019215059A1 - Semiconducting nanoparticle

Info

Publication number: WO2019215059A1
Application number: PCT/EP2019/061487
Authority: WO
Inventors: Nathan GRUMBACH; Shany NEYSHTADT
Original assignee: Merck Patent Gmbh
Priority date: 2018-05-09
Filing date: 2019-05-06
Publication date: 2019-11-14
Also published as: TW202003793A

Abstract

The present invention relates to a semiconducting light emitting nanoparticle.

Description

Title of the invention

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.

For example, Inorganic Chem., (2016), 55, 8351 -8386 discloses ln(Zn)P / ZnS nanocrystals fabricated with using Zn-undecylenate or Zn-stearate in ln(Zn)P core synthesis process.

Nano letters 2008, Vol.8, No.10, 3394-3397 mentions a hydrofluoric acid (HF) treatment of InP nanocrystals.

Chemistry Letters Vol.37, No.8 pp856 - 857 describes a photoetching of the InP nanocrystals with hydrogen fluoride treatment.

Patent Literature

No patent literature

Non- Patent Literature

1. Inorganic Chem., (2016), 55, 8351 -8386

2. Nano letters 2008, Vol.8, No.10, 3394-3397

3. Chemistry Letters Vol.37, No.8 pp856 - 857

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 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, improving charge injection, optimizing fabrication process of nanoparticle, environmentally more friendly and safer fabrication process.

The inventors aimed to solve one or more of the above-mentioned problems.

Then it was found a novel semiconducting light emitting nanoparticle comprising at least a first semiconducting nanosized material, and a metal carboxylate, preferably the nanoparticle comprises the first semiconducting nanosized material and a metal carboxylate in this sequence, wherein said first semiconducting nanosized material comprises at least a 1 ^st element selected from the group consisting of group 13 elements of the periodic table and group 12 elements of the periodic table, and a 2^nd element selected from the group consisting of group 15 elements of the periodic table and group 16 elements of the periodic table, preferably said 1^st element is selected from group 13 elements of the periodic table and said 2^nd element is selected from group 15 elements, more preferably said 1^st element is In or Ga and said 2^nd element is P or As, more preferably said 1^st element is In and said 2^nd element is P, wherein said metal carboxylate is represented by following chemical formula (I),

[M(0₂CR¹) (0₂CR²)] - (I) 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. In another aspect, the present invention relates to a process for preparing the semiconducting light emitting nanoparticle, wherein the process comprises at least following steps:

(a) preparing of a first semiconducting nanosized material in a solution, wherein said first semiconducting nanosized material comprises at least a 1^st element selected from the group consisting of group 13 elements of the periodic table and group 12 elements of the periodic table, and a 2^nd element selected from the group consisting of group 15 elements of the periodic table and group 16 elements of the periodic table, in the presence of a ligand source and optionally a zinc salt to form the first semiconducting nanosized material, preferably said ligand source is selected from one or more members of the group consisting of carboxylic acids, metal carboxylate ligands, phosphines, phosphonic acids, metal-phosphonates, amines, quaternary ammonium carboxylate salts, metal phosphonates and metal halides, more preferably myristic acid, lauric acid, stearate, oleate, myristate, laurate, phenyl acetate indium myristate, or an indium acetate;

(b) subjecting said first semiconducting nanosized material to a surface treatment with a metal carboxylate or a metal carboxylate solution, wherein said metal carboxylate is represented by following chemical formula (I),

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.

In another aspect, the present invention further relates to 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, 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 the semiconducting light emitting nanoparticle 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. ln another aspect, the present invention relates to use of the

semiconducting light emitting nanoparticle, 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 said 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 a and Figure 1 b: highlight the evolution of the absorption spectra and emission spectra of the semiconducting light emitting nanoparticle respectively, during the treatment of working example 1.

Figure 2a and Figure 2b: highlight the evolution of the absorption spectra and emission spectra of the semiconducting light emitting nanoparticles respectively, during the treatment of working example 14.

Detailed description of the invention

- Semiconducting light emitting nanoparticle

According to the present invention, said semiconducting light emitting nanoparticle comprises at least a first semiconducting nanosized material, and a metal carboxylate, preferably the nanoparticle comprises the first semiconducting nanosized material and a metal carboxylate in this sequence, wherein said first semiconducting nanosized material comprises at least a 1^st element selected from the group consisting of group 13 elements of the periodic table and group 12 elements of the periodic table, and a 2^nd element selected from the group consisting of group 15 elements of the periodic table and group 16 elements of the periodic table, preferably said 1^st element is selected from group 13 elements of the periodic table and said 2^nd element is selected from group 15 elements, more preferably said 1^st element is In or Ga and said 2^nd element is P or As, more preferably said 1^st element is In and said 2^nd element is P, wherein said metal carboxylate is represented by following chemical formula (I),

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. In a preferred embodiment of the present invention, said semiconducting light emitting nanoparticle mainly consisting of or consisting of a first semiconducting nanosized material, and a metal carboxylate.

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. 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.

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.

For example, CdS, CdSe, CdTe, ZnS, ZnSe, ZnSeS, ZnTe, ZnO, GaAs, GaP, GaSb, HgS, HgSe, HgSe, HgTe, In As, InP, InPS, InPZnS, InPZn, InPZnSe, InCdP, InPCdS, InPCdSe, InGaP, InGaPZn, InSb, AIAs, AIP, AlSb, CU2S, Cu2Se, CulnS2, CulnSe2, Cu2(ZnSn)S₄, Cu2(lnGa)S₄, T1O2 alloys and a combination of any of these can be used. In a preferred embodiment of the present invention, the first semiconducting nanosized material is represented by the following formula (VI), or formula (VI^'), - I Q -

lni_-xGaxZn_zP (VI) wherein 0£x£1 , 0£z£1 , even more preferably the first semiconducting nanosized material is InP, lnxZn_zP, or lni_-xGa_xP.

A person skilled in the art can easily understand that there is a counter ion in or around the first semiconducting nanosized material and thus, the chemical formula (VI) is electrically neutral. lni_-x-2/3zGa_xZn_zP (VI^') wherein 0£x£1 , 0£z£1 , even more preferably the first semiconducting nanosized material is InP, lni-2_/3_zZn_zP, or lni_-xGa_xP.

In case of Ihi-_2/3zZh_zR, x is 0, and 0<z£1. And Zn atom can be 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 0.07 and 1 .

Thus, in some embodiments of the present invention, the first

semiconducting nanosized material further comprises a Zn atom, preferably said first semiconducting nanosized material consists of the 1^st elements, the 2^nd elements and Zn atoms, more preferably the first semiconducting nanosized material is InP: Zn.

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.

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 a preferred embodiment of the invention, said semiconducting light emitting nanoparticle does not have a shell layer.

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%.

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,

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. 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.

Preferably, the determination of the full width half maximum (FWFIM) 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 are found and the difference between their two wavelength values are taken to give the FWHM parameter.

In some embodiments of the present invention, the nanoparticle can further comprise a second semiconducting material as a shell layer.

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 second

semiconducting material 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 i^{st element} is Zn, and the 2^nd 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 (VII),

ZnSxSe_yTe_z, - (VII) wherein 0£x<1 , 0£y<1 , 0£z<1 , and x+y+z=1 , preferably, the shell layer is ZnSe, ZnS_xSe_y, ZnSeyTe_zor ZnS_xTe_z.

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 ZnS_xSe_y, ZnSe_yTe_z, or ZnS_xTe_z, more preferably it is ZnS_xSe_y. The ratio of y/x is preferably larger than 0.5, more preferably larger than 1 and even more preferably larger than 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 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.

In a preferred embodiment of the present invention, the 2^nd shell layer is represented by following formula (VII^'),

ZnSxSe_yTe_z, - (VII^') wherein the formula (VI^'), 0£x<1 , 0£y<1 , 0£z<1 , and x+y+z=1 , preferably, the shell layer is ZnSe, ZnS_xSe_y, ZnSe_yTe_z, or ZnS_xTe_zwith the proviso that the shell layer and the 2^nd shell layer is not the same.

In some embodiments of the present invention, said 2^nd shell layer can be an alloyed shell layer or a graded shell layer, preferably said graded shell layer is ZnS_xSe_y, ZnSe_yTe_z, or ZnS_xTe_z, more preferably it is ZnS_xSe_y.

In some embodiments of the present invention, the semiconducting light emitting nanoparticle can further comprise one or more additional shell layers onto the 2^nd 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. For example, CdSe/CdS, CdSeS/CdZnS, CdSeS/CdS/ZnS, ZnSe/CdS, CdSe/ZnS, InP/ZnS, InP/ZnSe, InP/ZnSe/ZnS, InZnP /ZnS, InZnP /ZnSe, InZnP /ZnSe/ZnS, InGaP/ZnS, InGaP/ZnSe, InGaP/ZnSe/ZnS, InZnPS / ZnS, InZnPS ZnSe, InZnPS /ZnSe/ZnS, ZnSe/CdS, ZnSe/ZnS or

combination of any of these, can be used. Preferably, InP/ZnS, InP/ZnSe, lnP/ZnSe_xSi_-x, lnP/ZnSe_xSi_-x/ZnS, InP/ZnSe/ZnS, InZnP /ZnS,

lnP/ZnSe_xTei_-x/ZnS, lnP/ZnSe_xTei_-x, InZnP /ZnSe, InZnP /ZnSe/ZnS, InGaP/ZnS, InGaP/ZnSe, InGaP/ZnSe/ZnS.

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

in another aspect, the present invention also relates to a process for preparing the semiconducting light emitting nanoparticle according to any one of claims 1 to 4, wherein the process comprises at least following steps: (a) preparing of a first semiconducting nanosized material in a solution, wherein said first semiconducting nanosized material comprises at least a 1^st element selected from the group consisting of group 13 elements of the periodic table and group 12 elements of the periodic table, and a 2^nd element selected from the group consisting of group 15 elements of the periodic table and group 16 elements of the periodic table, in the presence of a ligand source and optionally a zinc salt to form the first semiconducting nanosized material, preferably said ligand source is selected from one or more members of the group consisting of carboxylic acids, metal carboxylate ligands, phosphines, phosphonic acids, metal-phosphonates, amines, quaternary ammonium carboxylate salts, metal phosphonates, metal halides and halides, more preferably myristic acid, lauric acid, stearate, oleate, myristate, laurate, phenyl acetate indium myristate, oleylamine, halides or an indium acetate, more preferably oleylamine or halides;

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. In a preferred embodiment of the present invention, the process comprises steps (a), (b) in this sequence.

- Step (a)

Even more preferably, said first semiconducting nanosized material precursor is a salt of the element of the group 13 of the periodic table selected from In and / or Ga, and said chemical element in group 15 of the periodic table is As, P, or Sb. In some embodiments of the present invention, the first semiconducting nanosized material 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 comprises at least InP, such as InP, InZnP, InGaP, InGaZnP, InPZnS, or InPZnSe. Preferably said first semiconducting nanosized material comprises at least InP and Zn, more preferably the first semiconducting nanosized material consist of InP and Zn.

In some embodiments of the present invention, Zn atom can be 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 some embodiments of the present invention, the InP based first semiconducting nanosized material such as InP, InZnP, InGaP, InGaZnP, InPZnS, or InPZnSe, can be prepared by using said 1^st element in step (a) is In, said 2^nd element in step (a) is P, and said first semiconducting nanosized material is prepared by reacting at least one indium precursor and at least one phosphor precursor or using or a magic sized cluster, more preferably said indium precursor is a metal halide represented by following chemical formula (II), metal carboxylate represented by following chemical formula (III), or a combination of these, and said phosphor precursor is an amino phosphine represented by following chemical formula (IV), alkyl silyl phosphine such as tris trimethyl silyl phosphine, or a combination of these,

lnX¹ ₃ (II)

wherein X¹ is a halogen selected from the group consisting of Cl , Br and I , [ln(0₂CR³)₃] - (III) 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 (IV) 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

(V),

ZnX²n (V)

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 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)si, 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, the said solution in step (a) and/ or step (b) comprises 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, alkyl chain lengths of said solvent can be C1 to C30, and the chain can be linear or branched. According to the present invention, as the solvent, an organic solvent represented by following chemical formula (VIII) can be used in step (a) preferably. ZR³R⁴R⁵ (VIII) wherein the formula, R³ is a hydrogen atom or an alkyl or alkene chain having 1 to 20 carbon atoms, R⁴ is a hydrogen atom or an alkyl or alkyne chain having 1 to 20 carbon atoms, R⁵ is an alkyne chain having 2 to 20 carbon atoms, Z is N, or P.

In a preferred embodiment of the present invention, Z is N.

0

More preferably, R³ and R⁴ are hydrogen atoms and R⁵ is an alkyne chain having 2 to 20 carbon atoms, and Z is N.

Even more preferably, the organic solvent represented by chemical formula₅ (VIII) is oleylamine.

In other words, to the surface of the first semiconducting nanosized material in step (a) is attached at least one ligand that is described by the chemical formula (VIII).

0

In some embodiments of the present invention, at least one ligand represented by chemical formula (VIII), and a halide ion delivered from the In-halide or Zn-halide precursor represented by chemical formula (VIII) are attached onto the surface of the first semiconducting nanosized material.5

- Step (b)

According to the present invention, in some embodiments, step (b) 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_n 250°C to 300°C, even more preferably from 250°C to 280°C. In some embodiments, the treatment time of step (b) is in the range from 10 min to 10 hours, preferably from 20 min to 4 hours, more preferably 30 min to 3 hours.

In some embodiments of the present invention, the total molar ratio between the metal carboxylate amount in step (b) and the first

semiconducting nanosized material amount is in the range from 500 to 50.000, preferably from 1.000 to 20.000, more preferably from 2.000 to 10.000.

- Cleaning process

According to the present invention, in some embodiments, the process can optionally comprise following step (c) after step (b), or after step (a) before step (b), or after step (a) before step (b) and after step (b),

(c) cleaning the first semiconducting nanosized 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 (c) 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 (c) comprises following step (C1 ), (C1 ) making a mixture solution by mixing the obtained solution from step (a) 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 (c) further comprises following step (C2),

(C2) 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 (C2) 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 (c) 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, to more effectively remove unreacted first semiconducting nanosized material precursors from the solution obtained in step (a) 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 (a) 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 (a) and to remove the ligands leftovers in the solution. More preferably, the cleaning solution removes the extra ligands and the un reacted precursor.

- Second semiconducting material

In some embodiments of the present invention, optionally, the process further comprises following step (d) after step (b), or after step (c)

(d) coating said the first semiconducting nanosized material with a source of a zinc chalcogenide to form a second semiconducting nanosized material, preferably said source of a zinc chalcogenide represents a mixture of a zinc salt and a sulphur and/or selenium compound. - 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. For example, as a first and a second cation shell precursor, one or more members of the group consisting of Zn-oleate, Zn-carboxylate, Zn-acetate, Zn-myristate, Zn-stearate, Zn-undecylenate, Zn-acetate-alkyl amine complexes, Zn-phosphonate, ZnCh, Znh, ZnBr2, Zn-palmitate, Cd-oleate, Cd-carboxylate, Cd-acetate, Cd-myristate, Cd-stearate and Cd- undecylenate, Cd-phosphonate, CdCh, Ga-oleate, Ga-carboxylate, Ga- acetate, Ga-myristate, Ga-stearate, Ga-undecylenate, Ga-acetylacetonate can be used, More preferably, one or more members of the group consisting of Zn-oleate, Zn-carboxylate, Zn-acetate, Zn-myristate, Zn- stearate, Zn-undecylenate and Zn-acetate-oleylamine complexes are used to coat said shell layer(s) onto the first semiconducting nanosized material.

Even more preferably, Zn-oleate is used as a first cation precursor for formation of the second semiconducting material. In some embodiment of the present invention, the metal halides

represented by chemical formula (IX) also can be used as one of the cation precursors instead of the cation precursors indicated above or in addition to the cation precursors indicated above.

M¹X¹n (IX)

wherein M¹ is Zn or Cd, X¹ is a halogen selected from the group consisting of Cl, Br and I, n is 2. 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 (d) 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 is0 obtained using this process.

In a preferred embodiment of the present invention, step (a), (b), and optionally step (c) and / or (d) are carried out in an inert condition, such as N2 atmosphere.

5

- Semiconducting light emitting nanoparticle

In another aspect, the present invention also relates to a semiconducting nanoparticle obtainable or obtained from the process of the present invention.

0

- Composition

In another aspect, the present invention also relates to composition comprising at least one semiconducting light emitting nanoparticle according to the present invention,

5

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_n 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, 2^nd edition (CRC Press, 2006), pp. 155 - pp. 338 (W.M.Yen, S.Shionoya and H. 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 M_w 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.

- 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. - Use

In another aspect, the present invention relates to use of the

- Optical medium

In another aspect, the present invention further relates to an optical medium comprising said semiconducting light emitting nanoparticle, or the

composition.

In 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.

In a preferable embodiment of the present invention, the optical medium comprises a plural of the light emitting nanoparticles.

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.

- 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.

Technical effects

The present invention provides one or more of following effects;

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, improving charge injection, optimizing fabrication process of nanoparticle, environmentally more friendly and safer fabrication process.

The working examples 1 - 15 below provide descriptions of the present invention, as well as an in-detail description of their fabrication.

Working Examples

Working Example 1 : Fabrication of a semiconducting light emitting nanoparticle - First semiconducting nanosized material synthesis

1g of lnCl3, 3g of ZnCh and 50 ml_ of oleylamine are mixed in a flask and degassed under inert atmosphere at 120°C. Then the temperature of the flask is raised to 190°C.

At 190°C, 4.5 nriL of tris-diethylamino phosphine is injected to the flask and it is kept at 190°C for 45 minutes. Then it is cooled down to the room temperature.

- Cleaning of the first semiconducting nanosized material

The first semiconducting nanosized materials in the 1.4 ml_ of the solution obtained in the previous synthesis step are then cleaned with a mixture of toluene and ethanol (the ratio of crude : toluene : ethanol : 1 : 2 : 4). The process is repeated 2 times and then the cleaned first semiconducting nanosized materials are dissolved in 1.4 ml_ of l -octadecene(ODE) to get a nanoparticle solution

- Treatment of the first semiconducting nanosized material

The solution obtained in the cleaning step is then heated up to 200°C and kept at 200°C for three hours in the presence of 0.4 mol of Zn(oleate) in 1.7 ml_ of ODE - Zn(oleate) solution.

Then a semiconducting light emitting nanoparticle comprising at least a first semiconducting nanosized material, and a metal carboxylate is obtained.

Figures 1 a and 1 b highlight the evolution of the absorption spectra and emission spectra of the semiconducting light emitting nanoparticle respectively, during the treatment. Core treatment is accompanied by a blue-shift of the absorption spectra, possible due to:

1. An etching of the core tied to the presence of acetic acid inside the solution.

2. Partial cation exchange of In -> Zn, resulting in increase of a band gap of the core.

Working Example 2: Fabrication of a semiconducting light emitting nanoparticle

Semiconducting light emitting nanoparticles are synthesized in the same manner as described in working example 1 except for 1.2 mmol of 0.4M Zn(oleate) in ODE is used in the treatment step.

Working Example 3: Fabrication of a semiconducting light emitting nanoparticle

Semiconducting light emitting nanoparticles are synthesized in the same manner as described in working example 1 except for 0.44 mmol of 0.4M Zn(oleate) in ODE is used in the treatment step. Working Example 4: Fabrication of a semiconducting light emitting nanoparticle

Semiconducting light emitting nanoparticles are synthesized in the same manner as described in working example 1 except for 0.28 mmol of 0.4M Zn(oleate) in ODE is used in the treatment step.

Working Example 5: Quantum Yield measurement and Trap Emission measurement

The Quantum Yield and the Trap Emission of the samples are measured as described in pages 10 to 12. Table 1 shows the results of the

measurements.

Table 1

Working Example 6: Fabrication of a semiconducting light emitting nanoparticle

Semiconducting light emitting nanoparticles are synthesized in the same manner as described in working example 1 except for the solution obtained in the cleaning step is heated up to 250°C and kept at 250°C for three hours in the presence of 1.1 ml_ of Zn-oleate (0.4M) OED solution in the treatment step.

Working Example 7: Fabrication of a semiconducting light emitting nanoparticle

Semiconducting light emitting nanoparticles are synthesized in the same manner as described in working example 1 except for the solution obtained in the cleaning step is heated up to 280°C and kept at 280°C for three hours in the presence of 1.1 ml_ of Zn-oleate (0.4M) OED solution in the treatment step.

Working Example 8: Fabrication of a semiconducting light emitting nanoparticle

Semiconducting light emitting nanoparticles are synthesized in the same manner as described in working example 1 except for the solution obtained in the cleaning step is heated up to 300°C and kept at 300°C for three hours in the presence of 1.1 ml_ of Zn-oleate (0.4M) OED solution in the treatment step.

Working Example 9: Quantum Yield measurement and Trap Emission measurement Quantum Yields and Trap emission values of the nanoparticles of working example 6, 7, 8 are measured in the same manner as described in working example 5. Table 2 shows the results of the measurements. Table 2

Working Example 10: Fabrication of a semiconducting light emitting nanoparticle

Semiconducting light emitting nanoparticles are synthesized in the same manner as described in working example 1 except for the solution obtained in the cleaning step is heated up to 280°C and kept at 280°C for two hours in the presence of 1.1 ml_ of Zn-oleate (0.4M) OED solution in the treatment step.

Working Example 11 : Fabrication of a semiconducting light emitting nanoparticle

Semiconducting light emitting nanoparticles are synthesized in the same manner as described in working example 1 except for the solution obtained in the cleaning step is heated up to 280°C and kept at 280°C for two hours in the presence of 1.1 ml_ of Zn-stearate (0.4M) OED solution in the treatment step.

Working Example 12: Fabrication of a semiconducting light emitting nanoparticle

Semiconducting light emitting nanoparticles are synthesized in the same manner as described in working example 1 except for the solution obtained in the cleaning step is heated up to 280°C and kept at 280°C for two hours in the presence of 1.1 mL of Zn-undecylenate (0.4M) OED solution in the treatment step.

Working Example 13: Quantum Yield measurement and Trap

Emission measurement

Quantum Yields and Trap emission values of the nanoparticles of working example 10, 11 , 12 are measured in the same manner as described in working example 5. Table 3 shows the results of the measurements. Table 3

Working Example 14: Fabrication of a semiconducting light emitting nanoparticle

Semiconducting light emitting nanoparticles are synthesized in the same manner as described in working example 1 expect for the solution obtained in the cleaning step is heated up to 280°C and kept at 280°C for three hours in the presence of 1.1 mL of Zn-undecylenate (0.4M) ODE solution in the treatment step.

Fig. 2a and Fig. 2b highlight the evolution of the absorption spectra and emission spectra of the semiconducting light emitting nanoparticles respectively, during the treatment.

Working Example 15: EDS measurement and elemental analysis of semiconducting light emitting nanoparticle

EDS measurement in FIRTEM of the nanoparticles obtained in working example 14 and elemental analysis are performed to estimate the composition of the nanoparticle. The elemental analysis is performed 7 times.

Table 4 shows the results of the elemental analysis.

Table 4

Claims

Patent Claims

1 . A semiconducting light emitting nanoparticle comprising at least a first semiconducting nanosized material, and a metal carboxylate, preferably the nanoparticle comprises the first semiconducting nanosized material and a metal carboxylate in this sequence, wherein said first semiconducting nanosized material comprises at least a 1 ^st element selected from the group consisting of group 13 elements of the periodic table and group 12 elements of the periodic table, and a 2^nd element selected from the group consisting of group 15 elements of the periodic table and group 16 elements of the periodic table, preferably said 1 ^st element is selected from group 13 elements of the periodic table and said 2^nd element is selected from group 15 elements, more preferably said 1 ^st element is In or Ga and said 2^nd element is P or As, more preferably said 1 ^st element is In and said 2^nd element is P, wherein said metal carboxylate is represented by following chemical formula (I),

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.

2. The nanoparticle according to claim 1 , wherein the first semiconducting nanosized material further comprises a Zn atom, preferably said first semiconducting nanosized material consists of the 1^st elements, the 2^nd elements and Zn atoms, more preferably the first semiconducting nanosized material is InP: Zn.

3. The nanoparticle according to claim 1 or 2, wherein 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%.

4. The nanoparticle according to any one of claims 1 to 3, wherein the trap emission value of the nanoparticle is in the range from 0.02 to 0.15, preferably 0.05 to 0.1.

5. A process for preparing the semiconducting light emitting nanoparticle according to any one of claims 1 to 4, wherein the process comprises at least following steps: (a) preparing a first semiconducting nanosized material in a solution, wherein said first semiconducting nanosized material comprises at least a 1^st element selected from the group consisting of group 13 elements of the periodic table and group 12 elements of the periodic table, and a 2^nd element selected from the group consisting of group 15 elements of the periodic table and group 16 elements of the periodic table, in the presence of a ligand source and optionally a zinc salt to form the first semiconducting nanosized material, preferably said ligand source is selected from one or more members of the group consisting of carboxylic acids, metal carboxylate ligands, phosphines, phosphonic acids, metal-phosphonates, amines, quaternary ammonium carboxylate salts, metal phosphonates, metal halides and halides, more preferably myristic acid, lauric acid, stearate, oleate, myristate, laurate, phenyl acetate indium myristate, oleylamine, halides or an indium acetate, more preferably oleylamine or halides; (b) subjecting said first semiconducting nanosized material to a surface treatment with a metal carboxylate or a metal carboxylate solution, wherein said metal carboxylate is represented by following chemical formula (I),

6. The process of claim 5, wherein said 1^st element in step (a) is In, said 2^nd element in step (a) is P, and said first semiconducting nanosized material is prepared by reacting at least one indium precursor and at least one phosphor precursor or using or a magic sized cluster being obtainable by reacting the indium precursor and the phosphor precursor, more preferably said indium precursor is a metal halide represented by following chemical formula (II), metal carboxylate represented by following chemical formula (III), or a combination of these, and said phosphor precursor is an amino phosphine represented by following chemical formula (IV), alkyl silyl phosphine such as tris trimethyl silyl phosphine, or a combination of these, lnX¹ ₃ (II) wherein X¹ is a halogen selected from the group consisting of Cl , Br and I ,

[ln(0₂CR³)₃] - (III) 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 (IV) wherein R⁴ and R⁵ are at each occurrence, independently or dependency, 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

(V), ZnX²n (V)

wherein X² is a halogen selected from the group consisting of Cl , Br and I , n is 2.

7. The process according to claim 5 or 6, wherein the step (b) 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.

8. The process according to any one of claims 5 to 7, wherein the treatment time of step (b) is in the range from 10 minutes to 10 hours, preferably from 20 minutes to 4 hours, more preferably 30 minutes to 3 hours.

9. The process according to any one of claims 5 to 8, wherein the total molar ratio between the metal carboxylate amount in step (b) and the first semiconducting nanosized material amount is in the range from 500 to 50.000, preferably from 1.000 to 20.000, more preferably from 2.000 to 10.000.

10. The process according to any one of claims 5 to 9, wherein said solution in step (b) and/or step (a) comprises 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.

11. The process according to any one of claims 5 to 10, wherein the process further comprises following step (c) after step (b), or after step (a) before step (b), or after step (a) before step (b) and after step (b),

12. The process according to any one of claims 5 to 11 , wherein step (c) 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.

13. The process according to any one of claims 5 to 12, wherein the first semiconducting nanosized material comprises at least InP, preferably said first semiconducting nanosized material comprises at least InP and Zn, more preferably the first semiconducting nanosized material consist of InP and Zn.

14. The process according to any one of claims 5 to 13, wherein the process further comprises following step (d) after step (b), or after step (c),

(d) coating said the first semiconducting material with a source of a zinc chalcogenide to form a second semiconducting material, preferably said source of a zinc chalcogenide represents a mixture of a zinc salt and a sulphur and/or selenium compound.

15. A semiconducting light emitting nanoparticle obtainable or obtained from the process according to any one of claims 5 to 14.

16. Composition comprising at least one semiconducting light emitting nanoparticle according to any one of claims 1 to 4, 15, and 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, and matrix materials.

17. Formulation comprising at least one semiconducting light emitting nanoparticle according to any one of claims 1 to 4, 15, or the composition according to claim 16, and at least one solvent.

18. Use of the semiconducting light emitting nanoparticle according to any one of claims 1 to 4, 15, or the composition according to claim 16, or the formulation according to claim 17 in an electronic device, optical device or in a biomedical device.

19. An optical medium comprising at least said semiconducting light emitting nanoparticle according to any one of claims 1 to 4, 15, or the composition according to claim 16.

20. The optical medium of claim 19, comprising an anode and a cathode, and at least one organic layer comprising at least one light emitting nanoparticle according to any one of claims 1 to 4, 15 or the composition of claim 16, 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.

21 . The optical medium of claim 19 or 20, wherein the organic layer comprises at least one light emitting nanoparticle according to any one of claims 1 to 4, 15 and a host material, preferably the host material is an organic host material.

22. An optical device comprising at least said optical medium according to any one of claims 19 to 21 .