WO2023056829A1 - Couche électroluminescente à points quantiques, procédé de préparation de couche électroluminescente à points quantiques et dispositif à diodes électroluminescentes à points quantiques - Google Patents

Couche électroluminescente à points quantiques, procédé de préparation de couche électroluminescente à points quantiques et dispositif à diodes électroluminescentes à points quantiques Download PDF

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WO2023056829A1
WO2023056829A1 PCT/CN2022/118788 CN2022118788W WO2023056829A1 WO 2023056829 A1 WO2023056829 A1 WO 2023056829A1 CN 2022118788 W CN2022118788 W CN 2022118788W WO 2023056829 A1 WO2023056829 A1 WO 2023056829A1
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quantum dot
quantum
emitting layer
layer
dot light
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PCT/CN2022/118788
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Chinese (zh)
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周礼宽
杨一行
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Tcl科技集团股份有限公司
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    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K11/00—Luminescent, e.g. electroluminescent, chemiluminescent materials
    • C09K11/02—Use of particular materials as binders, particle coatings or suspension media therefor
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K11/00—Luminescent, e.g. electroluminescent, chemiluminescent materials
    • C09K11/08—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials
    • C09K11/88—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials containing selenium, tellurium or unspecified chalcogen elements
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K50/00—Organic light-emitting devices
    • H10K50/10—OLEDs or polymer light-emitting diodes [PLED]
    • H10K50/11—OLEDs or polymer light-emitting diodes [PLED] characterised by the electroluminescent [EL] layers
    • H10K50/115—OLEDs or polymer light-emitting diodes [PLED] characterised by the electroluminescent [EL] layers comprising active inorganic nanostructures, e.g. luminescent quantum dots
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K2101/00—Properties of the organic materials covered by group H10K85/00

Definitions

  • the present application relates to the field of display technology, in particular to a quantum dot light emitting layer, a preparation method of the quantum dot light emitting layer and a quantum dot light emitting diode device.
  • Quantum dot light-emitting diode is an ideal solution for next-generation display technology, because quantum dots have nearly 100% luminous efficiency, high color purity (luminous peak width less than 25nm) and adjustable wavelength (from ultraviolet to infrared), etc. Excellent luminescence characteristics and chemical/photochemical stability of inorganic crystals can also use large-area, high-yield solution processing methods to achieve flexible displays with high color gamut, high contrast, fast response, high cost performance, and low energy consumption. It has been studied and paid attention to by many scientific researchers at home and abroad.
  • the device consists of an anode (Anode), a hole injection layer (HIL), a hole transport layer (HTL), an emission layer (EML), an electron transport layer (ETL) and a cathode (Cathode).
  • the emission layer is It is prepared by the solution method of quantum dot nanoparticles, and the quantum dot nanoparticles are arranged in a layer-by-layer stacking manner; when the device is working normally, electrons and holes are injected into the quantum dot light-emitting layer through the anode and cathode through the transport layer for further processing.
  • Composite glow Common quantum dot nanoparticles are generally in a regular spherical or cubic structure.
  • the red, green, and blue primary color quantum dots obtained by the existing process have a particle size distribution between 6-15nm, and the quantum dot film is obtained through the solution process, including spin coating, spray coating, transfer printing and other printing processes, quantum dots and quantum dots There is a noticeable gap between them, see Figure 1.
  • the existence of gaps inside the light-emitting layer leads to more defect states at the interface, which easily captures carriers and produces non-radiative recombination, resulting in poor optoelectronic performance of the device.
  • the present application provides a quantum dot light-emitting layer, a preparation method of the quantum dot light-emitting layer and a quantum dot light-emitting diode device, which can solve the problem of carrier transport difficulties caused by quantum dot gaps in the light-emitting layer of QLED devices and defect capture at the interface
  • the problem of carriers can solve the resulting problems of low current efficiency and poor stability of QLED devices, so as to meet the needs of commercial applications for high efficiency and reliability of QLED devices.
  • the present application provides a quantum dot light-emitting layer, the quantum dot light-emitting layer includes a quantum dot material and a host material, the quantum dot material includes a first quantum dot, and the host material is filled in the first in the gaps between the quantum dots;
  • the first quantum dot is a core-shell quantum dot, including a core layer and a shell layer; the bandgap width of the host material is greater than or equal to the bandgap width of the shell material of the first quantum dot.
  • the difference between the bandgap width of the host material and the bandgap width of the outermost shell layer material of the first quantum dot is less than or equal to 0.8eV.
  • the mass ratio of the first quantum dots to the host material is 100:5-20.
  • the quantum dot material further includes second quantum dots, and the bandgap width of the second quantum dots is greater than or equal to the bandgap width of the outermost shell layer material of the first quantum dots.
  • the lattice mismatch between the host material and the shell material of the first quantum dot is less than or equal to 5%;
  • the lattice mismatch between the host material and the second quantum dots is less than or equal to 5%.
  • the mass ratio of the first quantum dots to the second quantum dots is 100:1-15; and, the total mass of the second quantum dots and the host material is equal to that of the first quantum dots
  • the mass ratio is 5% to 20%.
  • the particle size of the second quantum dots is 2-5 nm
  • the material of the second quantum dot is selected from one of CdS, CdTe, CdSeTe, CdZnSe, CdZnS, CdSeS, ZnSe, ZnSeS, ZnS, PbS, PbSeS, InZnP and InGaP.
  • the first quantum dot is a Type I core-shell quantum dot
  • the core layer material of the first quantum dot is selected from CdSe, CdS, CdTe, CdSeTe, CdZnS, PbSe, ZnTe, CdSeS, PbS, PbTe, HgS, HgSe, HgTe, GaP, GaAs, InP, InAs, InZnP and InGaP a kind of
  • the shell material of the first quantum dot is selected from one of CdS, CdTe, CdSeTe, CdZnSe, CdZnS, CdSeS, ZnSe, ZnSeS, ZnS, PbS, PbSeS, InZnP and InGaP.
  • the host material is a chalcogenide material; the host material is selected from one of cadmium sulfide, zinc sulfide, indium sulfide, lead sulfide and gallium sulfide.
  • the present application provides a method for preparing a quantum dot luminescent layer, comprising the following steps:
  • Step 1 using quantum dot materials to prepare a quantum dot light-emitting layer film
  • Step 2 Filling the host material into the gaps between the quantum dots in the quantum dot light-emitting layer film by using a continuous ion layer adsorption reaction method to obtain the quantum dot light-emitting layer.
  • the quantum dot material includes at least one of first quantum dots or second quantum dots; for the quantum dot material including the first quantum dots and the second quantum dots, the first quantum dots
  • the bandgap width of the second quantum dot is greater than or equal to the bandgap width of the outermost shell material of the first quantum dot;
  • the first quantum dot is a Type I core-shell quantum dot;
  • the core layer material of the first quantum dot is selected from CdSe, CdS, CdTe, CdSeTe, CdZnS, PbSe, ZnTe, CdSeS, PbS, PbTe, HgS, HgSe , HgTe, GaP, GaAs, InP, InAs, InZnP and InGaP;
  • the shell material of the first quantum dot is selected from CdS, CdTe, CdSeTe, CdZnSe, CdZnS, CdSeS, ZnSe, ZnSeS, ZnS, PbS , one of PbSeS, InZnP and InGaP;
  • the particle diameter of the second quantum dot is 2-5nm; the material of the second quantum dot is selected from CdS, CdTe, CdSeTe, CdZnSe, CdZnS, CdSeS, ZnSe, ZnSeS, ZnS, PbS, PbSeS, InZnP and InGaP kind of.
  • the host material is a chalcogenide material, and the bandgap width of the host material is greater than or equal to the bandgap width of the shell material of the first quantum dot;
  • the difference between the bandgap width of the host material and the bandgap width of the outermost shell material of the first quantum dot is less than or equal to 0.8eV;
  • the lattice mismatch between the host material and the shell material of the first quantum dot is less than or equal to 5%.
  • the step of preparing the quantum dot light-emitting layer by the continuous ion layer adsorption reaction method includes: continuously soaking the quantum dot light-emitting layer film after annealing in the alcohol phase solution of the metal cation precursor and the alcohol of the sulfur precursor phase solution; cycle through the above steps of soaking.
  • the step of preparing the quantum dot light-emitting layer by the continuous ion layer adsorption reaction method comprises:
  • the above steps are repeated 2 to 10 times to fill the gaps of the quantum dot light-emitting layer with the host material, and then anneal at 100 to 150° C. for 1 to 15 minutes to remove residual alcohol solvent.
  • the metal cation precursors include metal cations of at least one of Cd, Zn, In, Pb and Ga.
  • the present application provides a quantum dot light-emitting diode device, including an anode, a cathode, and a quantum dot light-emitting layer disposed between the anode and the cathode, wherein the quantum dot light-emitting layer includes a quantum dot material and a host material, the quantum dot material includes a first quantum dot, and the host material is filled in the gap between the first quantum dots; the first quantum dot is a core-shell quantum dot, including a core layer and a shell layer; the bandgap width of the host material is greater than or equal to the bandgap width of the shell material of the first quantum dot;
  • the quantum dot luminescent layer is prepared by the following preparation method:
  • Step 1 using quantum dot materials to prepare a quantum dot light-emitting layer film
  • Step 2 Filling the host material into the gaps between the quantum dots in the quantum dot light-emitting layer film by using a continuous ion layer adsorption reaction method to obtain the quantum dot light-emitting layer.
  • the quantum dot material includes at least one of first quantum dots or second quantum dots; for the quantum dot material including the first quantum dots and the second quantum dots, the first quantum dots
  • the bandgap width of the second quantum dot is greater than or equal to the bandgap width of the outermost shell material of the first quantum dot;
  • the first quantum dot is a Type I core-shell quantum dot;
  • the core layer material of the first quantum dot is selected from CdSe, CdS, CdTe, CdSeTe, CdZnS, PbSe, ZnTe, CdSeS, PbS, PbTe, HgS, HgSe , HgTe, GaP, GaAs, InP, InAs, InZnP and InGaP;
  • the shell material of the first quantum dot is selected from CdS, CdTe, CdSeTe, CdZnSe, CdZnS, CdSeS, ZnSe, ZnSeS, ZnS, PbS , one of PbSeS, InZnP and InGaP;
  • the particle diameter of the second quantum dot is 2-5nm; the material of the second quantum dot is selected from CdS, CdTe, CdSeTe, CdZnSe, CdZnS, CdSeS, ZnSe, ZnSeS, ZnS, PbS, PbSeS, InZnP and InGaP a kind of
  • the difference between the bandgap width of the host material and the bandgap width of the outermost shell material of the first quantum dot is less than or equal to 0.8eV;
  • the lattice mismatch between the host material and the shell material of the first quantum dot is less than or equal to 5%.
  • the core layer material of the first quantum dot is selected from CdSe
  • the shell material of the first quantum dot is selected from CdS
  • the first quantum dot is a red quantum dot
  • the first quantum dot The particle size is 14nm
  • the host material is CdS.
  • the quantum dot light emitting diode device further includes a hole injection layer, a hole transport layer and an electron transport layer, the hole transport layer is arranged between the anode and the quantum dot light emitting layer, the The hole injection layer is arranged between the anode and the hole transport layer, and the electron transport layer is arranged between the cathode and the quantum dot light emitting layer.
  • the material of the hole injection layer is selected from one or more of PEDOT:PSS, nickel oxide, molybdenum oxide, tungsten oxide, vanadium oxide, molybdenum sulfide, tungsten sulfide or copper oxide;
  • the material of the hole transport layer is selected from one or more of PVK, Poly-TPD, CBP, TCTA or TFB;
  • the material of the electron transport layer is selected from one or more of n-type ZnO, TiO 2 , SnO, Ta 2 O 3 , AlZnO, ZnSnO, InSnO, Alq 3 , Ca, Ba, CsF, LiF or CsCO 3 ;
  • the material of the anode is selected from one or more of indium tin oxide, fluorine-doped tin oxide, indium zinc oxide, graphene or carbon nanotubes;
  • the material of the cathode is selected from one or more of Al, Ca, Ba or Ag.
  • the quantum dot light-emitting layer of the present application fills the gap of the quantum dot light-emitting layer through the host material, so as to obtain the continuity of the carrier transport process in the device and passivate the quantum dot surface defects to reduce the probability of carrier capture, thereby improving the device optoelectronic performance and stability.
  • the quantum dot luminescent layer of the present application uses the host material to fill the gap between the quantum dots and the quantum dots through the continuous ion layer adsorption reaction method (SILAR), effectively eliminating the gaps between the quantum dots, so that the obtained quantum dot luminescent layer can Guarantee the uninterrupted transport of carriers in the continuous phase.
  • the filled host material passivates the surface of quantum dots, reduces the possibility of interface defects trapping carriers, and reduces non-radiative recombination, thereby improving the carrier transport process in the device and reducing internal defects in the light-emitting layer, further improving the optoelectronics of the device. performance and stability.
  • the QLED device obtained in the present application has excellent current efficiency and stability, and meets the requirements of commercial applications for high efficiency and reliability of the QLED device.
  • Fig. 1 is a schematic diagram of quantum dot stacking in the light-emitting layer of a comparative device provided by the present application;
  • Fig. 2 is a schematic diagram 1 of quantum dot stacking in the quantum dot light-emitting layer of the device provided by the embodiment of the present application;
  • Fig. 3 is a second schematic diagram of quantum dot stacking in the quantum dot light-emitting layer of the device provided by the embodiment of the present application;
  • Fig. 4 is a schematic structural diagram of a quantum dot light-emitting diode device provided in an embodiment of the present application
  • Fig. 6 is the electroluminescent spectrogram of the quantum dot light-emitting diode device provided in Example 4 of the present application;
  • FIG. 7 is a schematic flow diagram of a method for preparing a quantum dot light-emitting layer provided in an embodiment of the present application.
  • Fig. 8 is a schematic flow chart of preparing a quantum dot light-emitting layer by using the continuous ion layer adsorption reaction method (SILAR) provided by the embodiment of the present application.
  • SILAR continuous ion layer adsorption reaction method
  • Embodiments of the present application provide a quantum dot light-emitting layer, a preparation method thereof, and a quantum dot light-emitting diode device. Each will be described in detail below. It should be noted that the description sequence of the following embodiments is not intended to limit the preferred sequence of the embodiments. In addition, in the description of the present application, the term “including” means “including but not limited to”. The terms first, second, third, etc. are used for designation only and do not impose numerical requirements or establish an order.
  • the term "and/or” is used to describe the relationship between associated objects, indicating that there may be three relationships, for example, "A and/or B" may indicate three situations: the first situation is that A exists alone ; The second case is the presence of A and B at the same time; the third case is the case of B alone, wherein A and B can be singular or plural respectively.
  • the term "at least one” means one or more, and “multiple” means two or more.
  • the terms “at least one”, “at least one of the following” or similar expressions refer to any combination of these items, including any combination of single or plural items.
  • “at least one (one) of a, b, or c” or “at least one (one) of a, b, and c” can be expressed as: a, b, c, a-b (that is, a and b ), a-c, b-c or a-b-c, wherein, a, b and c can be single or multiple respectively.
  • electrons and holes are injected into the wide bandgap shell layer in the quantum dot light-emitting layer structure through the cathode and anode via the transport layer, and then injected into the quantum dot core by energy transfer for radiative composite light emission; among them,
  • the gap between the quantum dots creates a discontinuous carrier transport channel, which increases the charge injection barrier.
  • the existence of the gap exposes the surface of the quantum dots, which is easy to generate defects to capture carriers and reduce the photoelectric conversion efficiency.
  • the quantum dots of inorganic nanomaterials and organic polymers belong to different phases.
  • the surface in contact is easy to generate more defect states; at the same time, a Type I heterojunction needs to be formed between the organic polymer material and the quantum dot light-emitting layer, so that electrons and holes can be effectively injected into the quantum dot, and the optional There are fewer types of organic polymers.
  • the embodiment of the present application provides a quantum dot light-emitting layer, as shown in FIG. 2 and FIG. 3 .
  • the quantum dot light-emitting layer includes a quantum dot material and a host material, wherein the quantum dot material includes first quantum dots, and the host material fills gaps between the first quantum dots.
  • the first quantum dots are core-shell quantum dots, and the bandgap width of the host material is greater than or equal to the bandgap width of the shell layer material of the first quantum dots.
  • the host material is used to fill the gaps between the quantum dot materials.
  • the gaps in the quantum dot luminescent layer are filled with the host material, the gaps between the quantum dots are reduced, and the elimination of the gaps can ensure the uninterrupted transmission of carriers in the continuous phase; at the same time, the filled host material can passivate the quantum dots.
  • the point surface reduces the possibility of interface defects trapping carriers and reduces non-radiative recombination, which in turn can improve the carrier transport process in the device and reduce internal defects in the light-emitting layer, providing a basis for improving the optoelectronic performance and stability of the device.
  • the particle size distribution of the red, green and blue primary color quantum dots obtained by the existing technology is between 6-15nm, and the quantum dot film is obtained through the solution process, including spin coating, spray coating, transfer printing and other printing processes, and the gap between quantum dots and quantum dots There is a clear gap, as shown in Figure 1. After filling with the host material, the gap of the quantum dot light-emitting layer is reduced, as shown in Figure 2.
  • the host material includes a chalcogen compound material.
  • the host material may be cadmium sulfide, zinc sulfide, indium sulfide, lead sulfide, or gallium sulfide.
  • the preparation of the host material can be obtained by a continuous ion layer adsorption reaction method.
  • the quantum dot material includes first quantum dots and/or second quantum dots.
  • the quantum dot material is composed of first quantum dots, as shown in FIG. 2 .
  • the mass ratio of the first quantum dots to the host material is related to the interstitial volume generated by different particle sizes of the quantum dots.
  • the mass ratio of the first quantum dots to the host material may be 100:5, 100:6, 100:7, 100:8, 100:9, 100:10, 100:11, 100:12, 100 :13, 100:14, 100:15, 100:16, 100:17, 100:18, 100:19 or 100:20.
  • the first quantum dot is a Type I core-shell quantum dot, including a core layer and a shell layer.
  • the core layer material of the first quantum dots includes: binary, multi-element, multi-element graded alloys composed of II-VI, III-V, and IV-VI elements, and quantum dots of core-shell components.
  • the shell material of the first quantum dot is selected to form a Type I core-shell structure material with the core.
  • the core layer material of the first quantum dot is selected from but not limited to CdSe, CdS, CdTe, CdSeTe, CdZnS, PbSe, ZnTe, CdSeS, PbS, PbTe, HgS, HgSe, HgTe, GaP, GaAs, InP, One of InAs, InZnP and InGaP.
  • the shell layer material of the first quantum dot is selected from but not limited to one of CdS, CdTe, CdSeTe, CdZnSe, CdZnS, CdSeS, ZnSe, ZnSeS, ZnS, PbS, PbSeS, InZnP and InGaP. It can be seen that the first quantum dot is a single-component core-shell quantum dot, that is, the core layer and the shell layer are respectively composed of a single-component quantum dot material.
  • the bandgap width (Eg) of the host material is greater than or equal to the bandgap width (Eg) of the outermost shell material of the first quantum dot, that is, Eg(host material)-Eg(first quantum dot point-shell) ⁇ 0.
  • the first quantum dot in the light-emitting layer acts as the nucleus and the host material to form a Type I heterogeneous energy level structure, which helps the carriers to be effectively confined inside the quantum dot; at the same time, the existence of no gap ensures The continuity of the carrier transport channel.
  • E g (host material)-E g (first quantum dot-shell layer) ⁇ 0.8eV can avoid the difficulty of carrier injection due to the excessive bandgap width of the host material, which will lead to an increase in the internal impedance of the device.
  • Factors that are not conducive to the stability of the device such as large, increased operating voltage, and Joule heat generation.
  • the lattice mismatch between the host material and the shell material of the first quantum dot is less than or equal to 5%. If the lattice mismatch is greater than 5%, crystal defects will be generated near the growth interface due to lattice stress, which will lead to the quenching of carriers in the non-radiative recombination center and reduce the radiative recombination efficiency.
  • the quantum dot material is composed of the first quantum dot and the second quantum dot, as shown in FIG. 3 .
  • the mass percentage of the second quantum dots in the quantum dot material is less than or equal to 20%.
  • the mass ratio of the first quantum dots, the second quantum dots to the host material is related to the interstitial volume produced by the different particle sizes of the quantum dots.
  • the mass ratio of the first quantum dots to the second quantum dots can be 100:1, 100:2, 100:3, 100:4, 100:5, 100:6, 100:7, 100:8 , 100:9, 100:10, 100:11, 100:12, 100:13, 100:14 or 100:15; further, the total mass of the second quantum dot and the host material is the same as the first
  • the mass ratio of a quantum dot is 5:100, 6:100, 7:100, 8:100, 9:100, 10:100, 11:100, 12:100, 13:100, 14:100, 15:100 , 16:100, 17:100, 18:100, 19:100 or 20:100.
  • the second quantum dot is selected from but not limited to one of CdS, CdTe, CdSeTe, CdZnSe, CdZnS, CdSeS, ZnSe, ZnSeS, ZnS, PbS, PbSeS, InZnP and InGaP.
  • the second quantum dots are nanoparticles with a particle diameter of 2-5 nm. It can be seen that the second quantum dot is a single-component quantum dot, that is, it is composed of a single-component quantum dot material.
  • bandgap width (Eg) of the second quantum dot is greater than or equal to the bandgap width (Eg) of the outermost shell material of the first quantum dot, that is, Eg(second quantum dot)-Eg (first quantum dot - shell) > 0.
  • the lattice mismatch between the host material and the second quantum dots is less than or equal to 5%.
  • the energy level of the second quantum dot is consistent with that of the host material.
  • the lattice parameter and bandgap width of the second quantum dot material are consistent with those of the host material.
  • the selection of the second quantum dot material may be consistent with the composition of the host material.
  • the host material may be understood as an additional shell structure of quantum dots.
  • the quantum dots are generally stacked in a tightly connected arrangement, as shown in Figure 1; at this time, the quantum dot light-emitting layer includes the following two possible situations: 1 When the distance between the centers of the quantum dot cores is > 10nm; 2When the distance between the centers of quantum dot cores is s ⁇ 10nm.
  • the spacing s between the centers of the luminescent nuclei of adjacent first quantum dots is less than or equal to 10 nm, there will be a relatively obvious energy resonance transfer effect (FRET), resulting in energy loss.
  • FRET energy resonance transfer effect
  • the principle is: first The second quantum dot material serves as the added spacer particles of the first quantum dots, the S between the first quantum dots is increased to the extent that the energy resonance transfer loss is reduced, and then the gap is filled with the host material to obtain the effect of the present invention.
  • the doping control mass percentage of the second quantum dots is in the range of less than or equal to 20%, avoiding the introduction of too many second quantum dot components with a wide bandgap, which will lead to an increase in the operating voltage of the device, resulting in device function at high current density Layer material aging problem. It can be seen that the function of the second quantum dot is to increase the distance between the first quantum dot luminescent nuclei and reduce the effect of energy resonance transfer (FRET). Uniformly distributed energy level barriers, the second quantum dot selects a material with uniformly distributed components and the same energy level as the filling host.
  • FRET energy resonance transfer
  • the quantum dot light-emitting layer is prepared from the first quantum dots and the host material, as shown in FIG. 2 .
  • the quantum dots in the light-emitting layer serve as the nucleus and the host material to form a Type I heterogeneous energy level structure, which helps the carriers to be effectively confined inside the quantum dots.
  • the embodiment of the present application also provides a method for preparing a quantum dot light-emitting layer, as shown in Figure 7, including the following steps:
  • Step 1 using quantum dot materials to prepare a quantum dot light-emitting layer film
  • Step 2 Fill the host material into the gap between the quantum dots in the quantum dot light-emitting layer film by using the continuous ion layer adsorption reaction method (SILAR) to obtain the quantum dot light-emitting layer.
  • SILAR continuous ion layer adsorption reaction method
  • the quantum dot material includes first quantum dots and/or second quantum dots.
  • the bandgap width of the second quantum dot is greater than or equal to the bandgap width of the outermost shell material of the first quantum dot.
  • the first quantum dot is a Type I core-shell quantum dot.
  • the core layer material of the first quantum dot is selected from but not limited to CdSe, CdS, CdTe, CdSeTe, CdZnS, PbSe, ZnTe, CdSeS, PbS, PbTe, HgS, HgSe, HgTe, GaP, GaAs, InP, InAs, InZnP and InGaP;
  • the shell material of the first quantum dot is selected from but not limited to CdS, CdTe, CdSeTe, CdZnSe, CdZnS, CdSeS, ZnSe, ZnSeS, ZnS, PbS, PbSeS, InZnP and InGaP any kind.
  • the particle diameter of the second quantum dot is 2-5 nm.
  • the material of the second quantum dot is selected from but not limited to any one of CdS, CdTe, CdSeTe, CdZnSe, CdZnS, CdSeS, ZnSe, ZnSeS, ZnS, PbS, PbSeS, InZnP and InGaP.
  • the host material is a chalcogen compound material
  • the bandgap width of the host material is greater than or equal to the bandgap width of the shell material of the first quantum dot.
  • the difference between the bandgap width of the host material and the bandgap width of the outermost shell material of the first quantum dot is less than or equal to 0.8eV.
  • the lattice mismatch between the host material and the shell material of the first quantum dot is less than or equal to 5%.
  • the step of preparing quantum dot luminescent layer by described adopting continuous ion layer adsorption reaction method comprises:
  • step S2 Place the quantum dot light-emitting layer film obtained in step S1 in the alcohol phase solution of the sulfur precursor, soak for 30s-1min, and wash continuously in the alcohol reagent;
  • the metal cation precursor includes metal cations of at least one of cadmium (Cd), zinc (Zn), indium (In), lead (Pb) and gallium (Ga).
  • the sulfur precursors are sulfur-containing salts containing metal sulfides and/or organic sulfides. For example, sodium sulfide, potassium sulfide, ammonium sulfide.
  • the metal cation precursor and the sulfur precursor can react to form metal sulfides, such as cadmium sulfide, zinc sulfide, indium sulfide , lead sulfide or gallium sulfide, that is, the host material in the quantum dot light-emitting layer.
  • metal sulfides such as cadmium sulfide, zinc sulfide, indium sulfide , lead sulfide or gallium sulfide, that is, the host material in the quantum dot light-emitting layer.
  • the second quantum dots are mixed with the first quantum dots in a certain proportion, and the second quantum dots are distributed in an approximately regular manner.
  • the distance between the first quantum dots is increased to reduce energy loss caused by resonance transfer.
  • the distance between centers of quantum dot cores is greater than 10 nm, only the first quantum dot can be used as the quantum dot material to prepare the quantum dot light-emitting layer.
  • the embodiment of the present application also provides a quantum dot light-emitting diode device (QLED device), including an anode, a cathode, and a quantum dot light-emitting layer arranged between the anode and the cathode, and the quantum dot light-emitting layer is the aforementioned quantum dot light-emitting layer.
  • QLED device quantum dot light-emitting diode device
  • the embodiment of the present application also provides a printed quantum dot display, including the above-mentioned quantum dot light-emitting diode.
  • the quantum dot light emitting diode comprises an anode 1, a hole injection layer 2, a hole transport layer 3, a light emitting layer 4, an electron transport layer 5 and a cathode 6, as shown in FIG. 4 .
  • the anode is selected from one or more of indium tin oxide, fluorine-doped tin oxide, indium zinc oxide, graphene, and carbon nanotubes;
  • the material of the hole injection layer is PEDOT:PSS, nickel oxide, oxide One or more of molybdenum, tungsten oxide, vanadium oxide, molybdenum sulfide, tungsten sulfide, copper oxide;
  • hole transport layer material is one or more of PVK, Poly-TPD, CBP, TCTA and TFB;
  • quantum The dot light-emitting layer includes red, green and blue multi-component mixed quantum dot light-emitting layer;
  • the material of the electron transport layer is n-type ZnO, TiO 2 , SnO, Ta 2 O 3 , AlZnO, ZnSnO, InSnO, Alq 3 , Ca, Ba One or more of , CsF, LiF, CsCO 3 ;
  • the cathode is
  • the life test of the device adopts the 128-channel life test system customized by Guangzhou New Vision Company.
  • the system architecture is driven by a constant voltage and constant current source to test the change of voltage or current; the photodiode detector and test system are used to test the change of the brightness (photocurrent) of the QLED; the luminance meter is used to test and calibrate the brightness (photocurrent) of the QLED.
  • This embodiment provides a quantum dot light-emitting layer, which includes a quantum dot material and a host material, and the host material fills the gap between quantum dots in the quantum dot material.
  • the quantum dot material in the quantum dot light-emitting layer of this embodiment is red quantum dot CdSe/CdS, with a particle size of about 14nm. After spin-coating to form a film, it is continuously soaked in cadmium acetate ethanol solution and sodium sulfide ethanol solution through SILAR, and cleaned with ethanol The reaction by-products were removed, and the cycle was carried out 3 times, and finally annealed on a hot plate at 120°C for 10 minutes to remove the residual ethanol solvent, and a red quantum dot light-emitting layer film in which the quantum dot gap was filled to form cadmium sulfide was obtained.
  • the main material of cadmium sulfide is consistent with the CdS composition of the quantum dot shell layer, and there will be no interface defects due to the problem of interface lattice matching. The reduction of the effect is also an important factor for the high performance of the device.
  • This embodiment provides a quantum dot light-emitting layer, which includes a quantum dot material and a host material, and the host material fills the gap between quantum dots in the quantum dot material.
  • the quantum dot material in the quantum dot light-emitting layer of this embodiment is blue quantum dot ZnCdSe/ZnS, with a particle size of about 8 nm. If only the blue quantum dot ZnCdSe/ZnS is used as the quantum dot material, the distance between the quantum dot central cores after stacking is less than 10nm, which will produce a significant FERT effect. In addition, when the particle size of the quantum dots is small, the specific surface area produced The larger the value, the higher the possibility of the existence of defect states. Therefore, in this embodiment, 10% by mass of zinc sulfide nanoparticles is added to the ZnCdSe/ZnS quantum dot solution, and the particle size of the zinc sulfide nanoparticles is about 4 nm.
  • the SILAR is continuously soaked in zinc acetate methanol solution and sodium sulfide methanol solution, and the reaction by-products are removed by washing with methanol.
  • the cycle was performed 5 times, and finally annealed on a hot plate at 100°C for 15 minutes to remove the residual methanol solvent to obtain a blue quantum dot light-emitting layer film in which the quantum dot gap was filled to form zinc sulfide.
  • QLED device quantum dot light-emitting diode device
  • Form the luminescent layer of CdSe/CdS red quantum dots please refer to the quantum dot luminescent layer in embodiment 1), 80 °C of annealing 10min remove the residual solvent of luminescent layer film;
  • the quantum dot luminescent layer film after the annealing is soaked in cadmium acetate ethanol Solution for 45s, then use ethanol to rinse the film for 1min, then soak in sodium sulfide ethanol solution for 45s, and then use ethanol to rinse the film for 1min to remove excess ions that adhere to the surface of the film and do not participate in the reaction.
  • the material is a red light-emitting layer thin film; on the light-emitting layer, an ethanol solution containing ZnO is spin-coated to obtain an electron transport layer; finally, an electroluminescent device is formed by evaporating an Ag cathode.
  • the electroluminescence spectrum analysis is performed on the quantum dot light-emitting diode device of this embodiment, as shown in FIG. 5 .
  • QLED device quantum dot light-emitting diode device
  • Form the luminescent layer of the ZnCdSe/ZnS blue quantum dot containing 10% mass percentage ZnS please refer to the quantum dot luminescent layer in embodiment 2), 80 °C of annealing 10min remove the solvent that luminescent layer thin film remains;
  • the quantum dot after annealing The luminescent layer film was soaked in zinc acetate methanol solution for 30s, then rinsed with methanol for 1min, then soaked in sodium sulfide methanol solution for 30s, and rinsed with methanol for 1min to remove excess ions that did not participate in the reaction adhering to the surface of the film, and cycled 5 times to obtain a blue light-emitting layer film filled with zinc sulf
  • the electroluminescence spectrum analysis is performed on the quantum dot light-emitting diode device of this embodiment, as shown in FIG. 6 .
  • the quantum dot light-emitting diode device of Comparative Example 1 is substantially the same as that of Example 1, except that the light-emitting layer is CdSe/CdS quantum dots.
  • the structure of the quantum dot light emitting layer in the quantum dot light emitting diode device can be referred to as shown in FIG. 1 .
  • the quantum dot light-emitting diode device of Comparative Example 2 is substantially the same as that of Example 2, except that the light-emitting layer is ZnCdSe/ZnS quantum dots.
  • the structure of the quantum dot light emitting layer in the quantum dot light emitting diode device can be referred to as shown in FIG. 1 .
  • Example 3 The photoelectric properties and lifetimes of the quantum dot light-emitting diode devices obtained in Example 3, Example 4, Comparative Example 1, and Comparative Example 2 were tested. The test results are shown in Table 1, and the device is recorded.
  • the electroluminescence peak position of the quantum dot light-emitting diode device prepared in Example 3 is 625nm, the half-peak width is 25nm, the external quantum efficiency (EQE) is 19.5%, and the lifetime (T 95 @1000nit) is 2300h.
  • the turn-on voltage (V T ) of the device was lowered by 0.2V compared with the device of Comparative Example 1.
  • the electroluminescence peak position of the quantum dot light-emitting diode device prepared in Example 4 is 472nm, the half-peak width is 22nm, the external quantum efficiency (EQE) is 17%, and the lifetime (T95@1000nit) is 150h. Because the blue quantum dots have a larger band gap, the turn-on voltage of the blue quantum dot light-emitting diode device is higher. After the light-emitting layer is processed by the scheme of the present invention, the turn-on voltage (VT) is reduced by 0.4 compared with the comparative example. V, that is, the quantum dot light-emitting diode device has lower resistance and better conductivity.
  • the external quantum efficiency (EQE) and lifetime (T95@1000nit) of the obtained quantum dot light-emitting diode device are lower than those of the luminescent
  • the layer fills the device properties of the host material. It can be seen that the quantum dot light-emitting diode device of the comparative example has more unpassivated defects on the surface of the quantum dots in the light-emitting layer and the unfilled gap between the quantum dots and the quantum dots, resulting in a relatively low charge transmission ability between the quantum dots. At the same time, the FRET generated between adjacent quantum dots leads to the loss of part of the energy, resulting in poor photoelectric performance of the comparative devices.
  • the quantum dot light-emitting layer of the present application eliminates the gap between quantum dots, thereby ensuring the uninterrupted transport of carriers in the continuous phase, and solves the problem of carrier transport difficulties and problems caused by the gap between quantum dots in the light-emitting layer of QLED devices.
  • This application uses the SILAR method (continuous ionic layer adsorption reaction method) to fill the gap of the quantum dot light-emitting layer with a wide-bandgap inorganic semiconductor as the main material to ensure the uninterrupted and continuous transmission of carriers inside the quantum dot light-emitting layer.
  • the lattice mismatch between the selected host material and the quantum dot shell is less than or equal to 5%, and the defect state density at the interface is effectively passivated after filling, reducing the possibility of interface defects trapping carriers and reducing non- Radiative recombination, in order to improve the carrier transport process in the device and reduce the internal defects of the light-emitting layer, improve the photoelectric performance and stability of the device.
  • the light-emitting layer in the QLED device is made of the first quantum dots with a Type I core-shell structure.
  • the role of the shell layer is to passivate the surface defect states of the quantum dot core and improve the fluorescence yield of the quantum dots.
  • it will Electron and hole wavefunctions are bound within the core, avoiding quenching of nonradiative recombination centers where exciton delocalization to shell surface states is avoided.
  • a quantum dot light-emitting layer, a preparation method of a quantum dot light-emitting layer and a quantum dot light-emitting diode device provided in the embodiments of the present application have been introduced in detail above, and specific examples are used in this paper to illustrate the principles and implementation methods of the present application , the description of the above embodiments is only used to help understand the method of the present application and its core idea; at the same time, for those skilled in the art, according to the idea of the present application, there will be changes in the specific implementation and application scope, In summary, the contents of this specification should not be construed as limiting the application.

Abstract

La présente invention concerne une couche électroluminescente à points quantiques, un procédé de préparation d'une couche électroluminescente à points quantiques, et un dispositif à diode électroluminescente à points quantiques (QLED). La couche électroluminescente à points quantiques comprend un matériau à points quantiques et un matériau de corps principal, le matériau à points quantiques comprenant des premiers points quantiques, et le matériau de corps principal remplissant des espaces entre les premiers points quantiques ; et les premiers points quantiques sont des points quantiques à enveloppe nucléaire, et la largeur d'intervalle de bande du matériau de corps principal n'est pas inférieure à la largeur d'intervalle de bande du matériau d'enveloppe le plus externe des premiers points quantiques. Par conséquent, l'efficacité et la stabilité actuelles d'une QLED sont améliorées.
PCT/CN2022/118788 2021-10-08 2022-09-14 Couche électroluminescente à points quantiques, procédé de préparation de couche électroluminescente à points quantiques et dispositif à diodes électroluminescentes à points quantiques WO2023056829A1 (fr)

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1988192A (zh) * 2006-12-12 2007-06-27 天津理工大学 柔性单层白光量子点电致发光器件及其制备方法
CN103772872A (zh) * 2013-12-27 2014-05-07 Tcl集团股份有限公司 量子点/丙烯酸酯聚合物纳米晶体复合物及制备方法和彩色转化膜
CN106585061A (zh) * 2016-12-06 2017-04-26 厦门世纳芯科技有限公司 一种高质量量子点荧光薄膜材料及其制备方法
CN109962170A (zh) * 2017-12-26 2019-07-02 Tcl集团股份有限公司 一种薄膜及其制备方法与qled器件
CN112186117A (zh) * 2020-11-26 2021-01-05 江汉大学 一种交流驱动型量子点发光二极管及其制备方法

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1988192A (zh) * 2006-12-12 2007-06-27 天津理工大学 柔性单层白光量子点电致发光器件及其制备方法
CN103772872A (zh) * 2013-12-27 2014-05-07 Tcl集团股份有限公司 量子点/丙烯酸酯聚合物纳米晶体复合物及制备方法和彩色转化膜
CN106585061A (zh) * 2016-12-06 2017-04-26 厦门世纳芯科技有限公司 一种高质量量子点荧光薄膜材料及其制备方法
CN109962170A (zh) * 2017-12-26 2019-07-02 Tcl集团股份有限公司 一种薄膜及其制备方法与qled器件
CN112186117A (zh) * 2020-11-26 2021-01-05 江汉大学 一种交流驱动型量子点发光二极管及其制备方法

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
ZHU YANSONG, WANG LIYAN, LAI YAN, CHI LIPING, LI ZELIN: "Thin films composed of irregular micro-block arrays of closely packed CdS nanoparticles for enhanced photoelectrochemical performance", ELECTROCHEMISTRY COMMUNICATIONS, ELSEVIER AMSTERDAM, NL, vol. 83, 1 October 2017 (2017-10-01), NL , pages 16 - 19, XP093055620, ISSN: 1388-2481, DOI: 10.1016/j.elecom.2017.08.014 *

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