WO2023205922A1 - 量子点发光二极管及其制备方法和显示面板 - Google Patents

量子点发光二极管及其制备方法和显示面板 Download PDF

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WO2023205922A1
WO2023205922A1 PCT/CN2022/088688 CN2022088688W WO2023205922A1 WO 2023205922 A1 WO2023205922 A1 WO 2023205922A1 CN 2022088688 W CN2022088688 W CN 2022088688W WO 2023205922 A1 WO2023205922 A1 WO 2023205922A1
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light
quantum dot
electrode
layer
emitting diode
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PCT/CN2022/088688
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English (en)
French (fr)
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冯靖雯
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京东方科技集团股份有限公司
北京京东方技术开发有限公司
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Priority to PCT/CN2022/088688 priority Critical patent/WO2023205922A1/zh
Priority to CN202280000859.5A priority patent/CN117322158A/zh
Publication of WO2023205922A1 publication Critical patent/WO2023205922A1/zh

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  • the present disclosure relates to the field of display, and in particular to a quantum dot light-emitting diode, a preparation method thereof, and a display panel.
  • Quantum Dot Light Emitting Diodes usually include a cathode, an anode and a quantum dot light-emitting layer with multiple quantum dot nanocrystals.
  • the quantum dot light-emitting layer is sandwiched between the cathode and the anode.
  • an electric field By applying an electric field to a quantum dot light-emitting diode, electrons and holes are moved into the quantum dot light-emitting layer.
  • the electrons and holes in the quantum dot light-emitting layer are trapped in the quantum dots and recombined, emitting photons.
  • Quantum dot LEDs have a narrower emission spectrum than organic LEDs. However, the light extraction efficiency of existing quantum dot light-emitting diodes is generally low, and it is difficult to further improve the luminous intensity (Emission Intensity).
  • the present disclosure aims to solve at least one of the technical problems existing in the prior art, and proposes a quantum dot light-emitting diode, a preparation method thereof, and a display panel.
  • embodiments of the present disclosure provide a quantum dot light-emitting diode, which includes: a first electrode, a second electrode, and a quantum dot light-emitting layer disposed between the first electrode and the second electrode, One of the first electrode and the second electrode is a reflective electrode, and the other is a transmissive electrode or a semi-transparent and semi-reverse electrode;
  • At least one light control layer is provided between the first electrode and the second electrode.
  • the light control layer is configured to form a microcavity structure with the reflective electrode to extract light from the quantum dot light-emitting diode.
  • the efficiency P satisfies: 25% ⁇ P ⁇ 98%.
  • the transmittance Q of the light control layer satisfies: 70% ⁇ Q ⁇ 100%
  • the reflectance R of the light control layer satisfies: 0 ⁇ R ⁇ 30%.
  • the thickness of the light regulation layer includes: 1 nm to 35 nm.
  • the refractive index of the light control layer includes: 0.1 to 0.3.
  • the material of the light regulation layer includes semiconductor material or metal material.
  • the material of the light regulation layer includes the metal material, and the light regulation layer is not in direct contact with the quantum dot light-emitting layer.
  • ⁇ 1 represents the phase shift caused by the reflection of light on the reflective electrode
  • ⁇ 2 represents the phase shift caused by the reflection of light on the light regulation layer
  • k represents the phase shift between the light regulation layer and the reflective electrode
  • n i and d i respectively represent the refractive index and thickness of the i-th functional media layer close to the reflective electrode
  • m 1 is a preconfigured positive integer
  • ⁇ represents the quantum The luminescence peak wavelength of the point light-emitting layer
  • i is an integer and 1 ⁇ i ⁇ k.
  • one of the first electrode and the second electrode is a reflective electrode, and the other is a semi-transparent and semi-counter electrode;
  • the functional dielectric layer located between the semi-transparent and semi-reflective electrode satisfies:
  • ⁇ 3 represents the phase shift caused by the reflection of light on the semi-transparent and semi-reflective electrode
  • s represents the number of the functional dielectric layers located between the semi-transparent and semi-reflective electrode
  • n j and d j respectively represent the refractive index and thickness of the jth functional dielectric layer close to the reflective electrode
  • m 2 is a preconfigured positive integer and m 2 >m 1
  • j is an integer and 1 ⁇ j ⁇ s.
  • one of the first electrode and the second electrode serves as the cathode of the quantum dot light-emitting diode, and the other serves as the anode of the quantum dot light-emitting diode;
  • An electron transport layer is provided between the cathode and the quantum dot light-emitting layer
  • a hole injection layer and a hole transport layer are provided between the anode and the quantum dot light-emitting layer.
  • the at least one light regulation layer includes: a first light regulation layer, and the material of the first light regulation layer includes a semiconductor material;
  • the first light regulation layer is located between the anode and the quantum dot light-emitting layer, and the absolute value of the difference between the HOMO energy level of the first light regulation layer and the HOMO energy level of the hole transport layer is greater than 1 eV. .
  • the at least one light regulation layer includes: a second light regulation layer, and the material of the second light regulation layer includes a semiconductor material;
  • the second light regulation layer is located between the cathode and the quantum dot light-emitting layer, and the absolute value of the difference between the HOMO energy level of the second light regulation layer and the HOMO energy level of the hole transport layer is less than 0.5 eV, the absolute value of the difference between the LUMO energy level of the second light regulation layer and the LUMO energy level of the hole transport layer is greater than 1 eV.
  • At least part of the surface of the light regulation layer away from the quantum dot light-emitting layer has a convex shape or a concave shape
  • At least part of the surface of the light regulation layer close to the quantum dot light-emitting layer has a convex shape or a concave shape.
  • it further includes: a base substrate, the first electrode is located on the base substrate, and the second electrode is located on a side of the first electrode away from the base substrate;
  • the first electrode is a reflective electrode
  • the second electrode is a semi-transparent and semi-counter electrode
  • the first electrode is a transmissive electrode
  • the second electrode is a reflective electrode
  • the reflective electrode serves as the anode of the quantum dot light-emitting diode, and the material of the reflective electrode includes a metal material;
  • a metal oxide electrode adjacent to the reflective electrode is provided on a side of the reflective electrode close to the quantum dot light-emitting layer.
  • an embodiment of the present disclosure also provides a display panel, which includes: the quantum dot light-emitting diode as provided in the first aspect.
  • the display panel includes: a first quantum dot light-emitting diode that emits blue light and a second quantum dot light-emitting diode that emits light of other colors, and at least the first quantum dot light-emitting diode is the quantum dot light-emitting diode;
  • the number of microcavity structures in the first quantum dot light-emitting diode is greater than the number of microcavity structures in the second quantum dot light-emitting diode.
  • embodiments of the present disclosure also provide a preparation method for preparing the quantum dot light-emitting diode described in the first aspect, including:
  • a first electrode, a second electrode, a quantum dot light-emitting layer and at least one light control layer are formed, the quantum dot light-emitting layer is located between the first electrode and the second electrode, the first electrode and the One of the second electrodes is a reflective electrode, and the other is a transmissive electrode or a semi-transparent and semi-reverse electrode.
  • the light control layer is located between the first electrode and the second electrode.
  • the light control layer is configured with The reflective electrode forms a microcavity structure, so that the light extraction efficiency P of the quantum dot light-emitting diode satisfies: 25% ⁇ P ⁇ 98%.
  • the light control layer is prepared through an evaporation process, a spin coating process or a printing process.
  • Figure 1 is a schematic cross-sectional view of a quantum dot light-emitting diode provided by an embodiment of the present disclosure
  • Figure 2 is a schematic cross-sectional view of a quantum dot light-emitting diode without a light control layer in an embodiment of the present disclosure
  • Figure 3 is a schematic cross-sectional view of a light control layer disposed between the hole transport layer and the quantum dot light-emitting layer in the quantum dot light-emitting diode shown in Figure 2;
  • Figure 4 is the simulated luminescence spectrum of the quantum dot light-emitting diodes shown in Figures 2 and 3;
  • Figure 5 is a simulated luminescence spectrum diagram of the light control layer in the quantum dot light-emitting diode shown in Figure 3 when it is at different thicknesses;
  • Figure 6 is a simulated luminescence spectrum diagram of the light control layer in the quantum dot light-emitting diode shown in Figure 3 under different refractive index conditions;
  • Figures 7 to 10 are schematic cross-sectional views of the light control layer located at different positions within the quantum dot light-emitting diode in embodiments of the present disclosure
  • Figure 11 is the simulated luminescence spectrum of the quantum dot light-emitting diodes shown in Figures 2 and 7 to 10;
  • Figure 12 is a luminous brightness-current efficiency relationship diagram of the quantum dot light-emitting diodes shown in Figures 2 and 10;
  • Figure 13 is a relationship diagram between the luminous brightness and external quantum efficiency of the quantum dot light-emitting diodes shown in Figures 2 and 10;
  • Figure 14 is a schematic cross-sectional view of yet another quantum dot light-emitting diode provided by an embodiment of the present disclosure.
  • FIG. 15 is a flow chart of a method for preparing a quantum dot light-emitting diode according to an embodiment of the present disclosure.
  • “About” or “approximately” as used herein includes the stated value and means that the measurement in question and the errors associated with the measurement of the particular quantity (i.e., limitations of the measurement system) are contemplated as would be contemplated by one of ordinary skill in the art. and within the determined acceptable deviation range for a specific value. For example, “about” may mean that the difference from the stated value is within one or more standard deviations, or within ⁇ 30%, 20%, 10%, 5%.
  • the highest occupied molecular orbital (“HOMO”) energy level or the lowest unoccupied molecular orbital (LUMO) energy level is expressed as an absolute value from a vacuum.
  • HOMO energy level or a LUMO energy level is referred to as 'deep', 'high', or 'large'
  • the HOMO energy level or LUMO energy level has a large relative to '0eV', i.e., a vacuum energy
  • 'OeV' That is the absolute value of the vacuum energy level.
  • FIG. 1 is a schematic cross-sectional view of a quantum dot light-emitting diode provided by an embodiment of the present disclosure.
  • the quantum dot light-emitting diode includes: a first electrode 1, a second electrode 2, a quantum dot light-emitting layer 3 arranged between the first electrode 1 and the second electrode 2, the first electrode 1 and the second electrode 2.
  • One of the electrodes 2 is a reflective electrode, and the other is a transmissive electrode or a semi-transparent and semi-reverse electrode; at least one light control layer 5 is provided between the first electrode 1 and the second electrode 2, and the light control layer 5 is configured with
  • the reflective electrode forms a microcavity structure, so that the light extraction efficiency P of the quantum dot light-emitting diode satisfies: 25% ⁇ P ⁇ 98%.
  • one of the first electrode 1 and the second electrode 2 serves as the anode of the quantum dot light-emitting diode, and the other serves as the cathode of the quantum dot light-emitting diode.
  • the quantum dot light-emitting layer 3 can be driven to emit light.
  • the microcavity structure can effectively improve the light extraction efficiency of the quantum dot light-emitting diode.
  • the light extraction efficiency of the quantum dot light-emitting diode is equal to the actual light emission amount of the quantum dot light-emitting diode (this disclosure is expressed by the luminous intensity of the quantum dot light-emitting diode) and the light emission amount of the quantum dot light-emitting layer 3 (this disclosure is expressed by the luminous intensity of the quantum dot light-emitting layer 3 luminous intensity).
  • the technical solution of the present disclosure provides at least one light control layer 5 between the first electrode 1 and the second electrode 2, and the light control layer 5 and the reflective electrode form a microcavity structure.
  • the microcavity effect based on the microcavity structure can This improves the light extraction efficiency of the quantum dot light-emitting diode, which is beneficial to increasing the luminous intensity of the quantum dot light-emitting diode.
  • the light control layer 5 is specifically a functional film layer with semi-transparent and semi-reflective properties.
  • the cavity length is of the same order of magnitude as the wavelength of the light wave.
  • light of a specific wavelength will be selected and enhanced, and the spectrum will be narrowed. This is the microcavity effect.
  • FIG. 1 only illustrates the situation where a layer of light control layer 5 is provided between the first electrode 1 and the second electrode 2. This situation only serves as an example. No limitation will be placed on the technical solution of the present disclosure.
  • the first electrode 1 serves as a reflective electrode
  • the second electrode 2 serves as a transparent electrode or a semi-transparent semi-counter electrode.
  • the light control layer 5 needs to be disposed between the quantum dot light-emitting layer 3 and the second electrode 2. At this time, there is a functional medium layer between the light control layer 5 and the reflective electrode: the quantum dot light-emitting layer 3.
  • each light control layer 5 can form a microcavity structure with the reflective electrode that can be used to improve the light extraction efficiency of the quantum dot light-emitting diode. In this case, no corresponding drawing is given.
  • ⁇ 1 represents the phase shift caused by the reflection of light on the reflective electrode
  • ⁇ 2 represents the phase shift produced by the reflection of light on the light regulation layer 5
  • k represents the functional dielectric layer located between the light regulation layer 5 and the reflective electrode
  • ⁇ represents the peak emission wavelength of the quantum dot light-emitting layer 3
  • i is an integer and 1 ⁇ i ⁇ k.
  • the quantum dot light-emitting layer 3 that is, the value of k is 1.
  • the microcavity structure formed by the light control layer 5 and the reflective electrode can achieve a strong microcavity effect.
  • one of the first electrode 1 and the second electrode 2 is a reflective electrode, and the other is a semi-transparent and semi-counter electrode (for example, in Figure 1, the first electrode 1 is a reflective electrode, and the second electrode 2 is a semi-transparent electrode.
  • Semi-counter electrode the functional dielectric layer located between the semi-transmissive semi-counter electrode and the reflective electrode satisfies:
  • ⁇ 3 represents the phase shift caused by the reflection of light on the semi-transparent and semi-reflective electrode
  • s represents the number of functional dielectric layers located between the semi-transparent and semi-reflective electrode and the reflective electrode
  • n j and d j respectively represent the number of layers close to the reflective electrode.
  • the refractive index and thickness of the j-th functional dielectric layer m 2 is a preconfigured positive integer (m 2 represents the modulus of the microcavity formed by the semi-transparent semi-reverse electrode and the reflective electrode) and m 2 > m 1 , j is an integer And 1 ⁇ j ⁇ s.
  • the light control layer 5 and the reflective electrode form a microcavity structure that enhances the light emission amount of the quantum dot light-emitting diode
  • the semi-transparent and semi-reflective electrode can also form a microcavity structure with the reflective electrode that enhances the light emission amount of the quantum dot light-emitting diode.
  • the microcavity structure formed by the semi-transparent counter electrode and the reflective electrode can achieve a strong microcavity effect.
  • the transmittance of the light control layer 5 is Q
  • the reflectance R of the light control layer 5 is 1-Q, where Q and R respectively satisfy: 70% ⁇ Q ⁇ 100%, 0 ⁇ R ⁇ 30 %.
  • the thickness of the light regulation layer 5 includes: 1 nm to 35 nm. It should be noted that in the expression of the range A to B in this disclosure, the limited range includes the two endpoint values of A and B.
  • the refractive index of the light control layer 5 includes: 0.1 ⁇ 0.3.
  • the material of the light regulation layer 5 includes semiconductor materials or metal materials (such as gold, silver, copper, aluminum, magnesium, lithium, etc.).
  • the light control layer 5 is made of a metal material
  • the light control layer 5 and the quantum dot light-emitting layer 3 are not in direct contact to avoid quenching of the quantum dots in the quantum dot light-emitting layer 3, causing the quantum dot light-emitting layer to The luminous intensity of 3 is reduced, which is not conducive to the improvement of the light output of quantum dot light-emitting diodes.
  • the thickness of the light control layer 5 is 1 nm to 10 nm to ensure that its transmittance is 70% ⁇ Q ⁇ 100%.
  • the amount of light emitted by the quantum dot light-emitting layer 3 may be reduced.
  • the light control layer 5 The existence of the microcavity effect forms a microcavity effect, which can still improve the overall light extraction efficiency of the quantum dot light-emitting diode to a certain extent compared to the quantum dot light-emitting diode without the light control layer 5 . See the examples below for specific situations.
  • the material of the light regulation layer 5 is a semiconductor material, there is no limit on the location of the light regulation layer 5 in principle.
  • FIG. 2 is a schematic cross-sectional view of a quantum dot light-emitting diode without a light control layer in an embodiment of the present disclosure.
  • FIG. 3 is a schematic cross-sectional view of a light control layer disposed between the hole transport layer 7 and the quantum dot light-emitting layer 3 in the quantum dot light-emitting diode shown in FIG. 2 .
  • a cathode is provided between the cathode and the quantum dot light-emitting layer 3.
  • Electron Transport Layer 4 Electron Transport Layer 4 (Electron Transport Layer, referred to as ETL), a hole injection layer 8 (Hole Injection Layer, referred to as HIL) and a hole transport layer 7 (Hole Transport Layer, referred to as HTL) are provided between the anode and the quantum dot light-emitting layer 3 ).
  • ETL Electron Transport Layer 4
  • HIL Hole Injection Layer
  • HTL Hole Transport Layer
  • the quantum dot light-emitting diode further includes a substrate substrate 6 , and the second electrode 2 is located on a side of the first electrode 1 away from the substrate substrate 6 .
  • the first electrode 1 is used as the anode and the second electrode 2 is used as the cathode, and the first electrode 1 is a reflective electrode, and the second electrode 2 is a semi-transparent and semi-reflective electrode or a transparent electrode.
  • the quantum dot light-emitting diode is a positive top-emitting quantum dot light-emitting diode.
  • the thin film transistor (TFT) array used to drive the quantum dot light-emitting diodes is located on the non-light-emitting side of the quantum dot light-emitting diodes, the thin film transistor array will not affect the quantum dot light-emitting diode.
  • the light emitted by point light-emitting diodes causes obstruction, so the light-emitting area of quantum dot light-emitting diodes can be designed to be relatively large, which is beneficial to increasing the pixel aperture ratio.
  • the material of the reflective electrode includes metallic material.
  • a metal oxide electrode 9 adjacent to the reflective electrode is provided on the side of the reflective electrode made of metal material close to the quantum dot light-emitting layer 3.
  • the material of the metal oxide electrode 9 is a transparent and conductive metal oxide material.
  • the material of the first electrode 1 includes a metal material with a high work function, including but not limited to at least one of nickel, platinum, vanadium, chromium, copper, zinc, and gold. .
  • a metal material with a high work function including but not limited to at least one of nickel, platinum, vanadium, chromium, copper, zinc, and gold.
  • its thickness can be designed to be relatively thick.
  • the thickness of the first electrode 1 as the reflective electrode is 70 nm to 150 nm, for example, 100 nm.
  • the material of the metal oxide electrode 9 includes, but is not limited to, metal oxides. Specifically, it may include zinc oxide (ZnO), indium oxide (InO), tin oxide (SnO), indium tin oxide (ITO), indium zinc oxide (IZO), Or at least one of fluorine-doped tin oxide (FTO).
  • the metal oxide electrode 9 mainly plays a role in work function matching, and its thickness can be designed to be relatively thin.
  • the thickness of the metal oxide electrode 9 is 5 nm to 12 nm, such as 8 nm.
  • the material of the hole injection layer 8 includes, but is not limited to, poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT: PSS), polythiophene, polyaniline, polypyrrole, and copper phthalocyanine.
  • PEDOT poly(3,4-ethylenedioxythiophene) polystyrene sulfonate
  • PDOT polystyrene sulfonate
  • polythiophene polyaniline
  • polypyrrole polypyrrole
  • copper phthalocyanine copper phthalocyanine
  • the material of the hole transport layer 7 includes, but is not limited to, p-type polymer materials and various p-type low molecular weight materials, such as polythiophene, polyaniline, polypyrrole, poly-3,4-ethylenedioxythiophene and Poly(sodium p-styrenesulfonate), 4,4'-cyclohexylene bis[N,N-bis(4-methylphenyl)aniline (TAPC) or 4,4',4"-tris(N- A mixture of carbazolyl)triphenylamine (TCTA) and N,N'-bis(1-naphthyl)-N,N'-diphenylbenzidine (NPB).
  • p-type polymer materials and various p-type low molecular weight materials such as polythiophene, polyaniline, polypyrrole, poly-3,4-ethylenedioxythiophene and Poly(sodium p-styrenesulfonate), 4,4'-cycl
  • the thickness of the hole injection layer 8 and the hole transport layer 7 is set according to the required hole transport rate.
  • the thickness of the hole injection layer 8 includes 20 nm ⁇ 30 nm, such as 24.5 nm; the thickness of the hole transport layer 7 includes 20 nm ⁇ 30 nm, such as 26.8 nm.
  • the materials of the quantum dot light-emitting layer 3 include but are not limited to cadmium (Cd)-free quantum dot materials or blue light cadmium-containing quantum dot materials; wherein, the cadmium-free quantum dot material can be indium phosphide (InP) quantum dots or InP-derived core shells.
  • Structural quantum dots such as InP/ZnSe/ZnS, InP/ZnSeS/ZnS; blue light cadmium-containing quantum dot materials can be CdS/ZnSe/ZnS, CdSe/ZnSe/ZnS, CdInS/ZnSe/ZnS.
  • the material of the quantum dot light-emitting layer 3 can also be other quantum dots, such as GaP/ZnSe, CsPbBr3/ZnS and other quantum dots.
  • the thickness of the quantum dot light-emitting layer 3 is 10 nm to 20 nm, such as 14.1 nm.
  • the material of the electron transport layer 4 includes, but is not limited to, at least one of zinc oxide (ZnO), magnesium zinc oxide (ZnMgO), aluminum zinc oxide (AZO), and magnesium aluminum zinc oxide.
  • the thickness of the electron transport layer 4 includes 5 nm to 20 nm, such as 8.9 nm.
  • the second electrode 2 may be a transparent electrode or a semi-transparent and semi-counter electrode.
  • the material of the second electrode 2 can be a conductive metal oxide material, which can specifically include at least one of zinc oxide, indium oxide, tin oxide, indium tin oxide, and indium zinc oxide. ;
  • the thickness of the transparent electrode formed of the metal oxide material is greater than 30 nm, for example, 70 nm.
  • the second electrode 2 can be made of a metal material with a lower functional function than the first electrode 1, including but not limited to aluminum, magnesium, calcium, sodium, potassium, titanium, and indium. , yttrium, lithium, gadolinium, silver, tin, lead, cesium, and barium; at this time, in order to ensure that the second electrode 2 has a certain conductivity and exhibits a semi-transparent and semi-reflective effect, its thickness cannot be set too thick or Too thin, optionally, the thickness of the semi-transmissive semi-counter electrode formed of metal material is 1 nm to 15 nm, such as 10 nm.
  • Figure 4 is a luminescence spectrum diagram based on the quantum dot light-emitting diode shown in Figures 2 and 3. As shown in Figure 4, in Figures 2 and 3, the thickness of the first electrode 1 (reflective electrode) is 100nm, the thickness of the metal oxide electrode 9 is 8nm, the thickness of the hole transport layer 7 is 24.5nm, and the thickness of the hole transport layer 7 is 24.5nm.
  • the thickness of the injection layer 8 is 26.8nm
  • the thickness of the quantum dot light-emitting layer 3 is 14.1nm
  • the material of the quantum dot light-emitting layer is a quantum dot material capable of emitting blue light
  • the thickness of the electron transport layer 4 is 8.9nm
  • the second electrode 2 It is a semi-transparent and semi-counter electrode and has a thickness of 10nm.
  • simulation is performed on the case where the material of the semi-transparent and semi-reflective medium shown in Figure 3 is a semiconductor material (refractive index is about 0.2) and the thickness is 10 nm.
  • the dual microcavity structure shown in Figure 4 (between the light control layer 5 and the reflective electrode)
  • a microcavity structure is formed between the semi-transparent counter electrode and the reflective electrode)
  • the light intensity is increased by about 32%
  • the half-peak width is narrowed from 39nm before optimization to 27nm.
  • the narrowing of the half-peak width means that the color of the light emitted by the quantum dot light-emitting diode is purer, which is beneficial to improving the color gamut of the display panel when it is applied to the display panel.
  • a quantum dot light-emitting diode emitting blue light was simulated to verify that the light extraction efficiency of the quantum dot light-emitting diode can be improved after setting the light control layer 5.
  • This situation is only exemplary. function, which will not limit the technical solution of the present disclosure.
  • the technical solution of the present disclosure can also be applied to quantum dot light-emitting diodes that emit light of other colors, such as red light quantum dot diodes that emit red light and green light quantum dot diodes that emit green light.
  • Figure 5 is a simulated luminescence spectrum diagram of the light control layer in the quantum dot light-emitting diode shown in Figure 3 when it is at different thicknesses.
  • the light regulation layer 5 in Figure 3 is made of semiconductor material and the refractive index is about 0.2
  • the conditions of the light regulation layer 5 with different thicknesses were simulated. From the simulation results shown in Figure 5, it can be seen that When the thickness of the light regulation layer 5 in the quantum dot light-emitting diode shown in Figure 3 is between 5 nm and 35 nm, the light emission intensity of the quantum dot light-emitting diode is improved compared to the light emission intensity of the quantum dot light-emitting diode shown in Figure 2.
  • Figure 6 is a simulated luminescence spectrum diagram of the light control layer in the quantum dot light-emitting diode shown in Figure 3 under different refractive index conditions.
  • the light regulation layer 5 in Figure 3 is made of semiconductor material and has a thickness of 10 nm
  • the conditions of the light regulation layer 5 with different refractive indexes were simulated. From the simulation results shown in Figure 6, it can be seen that when When the refractive index of the light control layer 5 in the quantum dot light-emitting diode shown in Figure 3 is between 0.1 and 0.3, the light emission intensity of the quantum dot light-emitting diode is improved compared to the light emission intensity of the quantum dot light-emitting diode shown in Figure 2.
  • This disclosure also simulates the case where the light control layer 5 is made of metal material and is located at other positions.
  • 7 to 10 are schematic cross-sectional views of the light control layer 5 located at different positions in the quantum dot light-emitting diode according to the embodiment of the present disclosure. As shown in Figures 7 to 10, in the case shown in Figure 7, the light regulation layer 5 is located between the metal oxide electrode 9 and the hole injection layer 8; in the case shown in Figure 8, the light regulation layer 5 is located in the hole.
  • the light regulation layer 5 is located between the quantum dot light-emitting layer 3 and the electron transport layer 4; in the case shown in Figure 10, the light regulation layer 5 is located between the electron transport layer 4 and the second electrode 2 .
  • Figure 11 is a simulated luminescence spectrum diagram of the quantum dot light-emitting diode shown in Figures 2 and 7 to 10.
  • the thickness of the first electrode 1 is 100nm
  • the thickness of the metal oxide electrode 9 is 8nm
  • the thickness of the hole transport layer 7 is 24.5nm
  • the thickness of the hole transport layer 7 is 24.5nm.
  • the thickness of the injection layer 8 is 26.8nm
  • the thickness of the quantum dot light-emitting layer 3 is 14.1nm
  • the thickness of the electron transport layer 4 is 8.9nm
  • the second electrode 2 is a semi-transparent and semi-counter electrode with a thickness of 10nm; in Figure 7 to Figure In 10, the light control layer 5 is made of metal material and has a thickness of 3 nm.
  • the light regulation layer 5 is provided between the metal oxide electrode 9 and the hole injection layer 8 as shown in Figure 7.
  • a light regulation layer 5 is provided between the quantum dot light-emitting layer 3 and the electron transport layer 4.
  • a light regulation layer 5 is provided between the electron transport layer 4 and the second electrode 2.
  • Figure 12 is a graph showing the relationship between luminous brightness and current efficiency of the quantum dot light-emitting diodes shown in Figures 2 and 10.
  • Figure 13 is a relationship diagram between the luminous brightness and the external quantum efficiency of the quantum dot light-emitting diodes shown in Figures 2 and 10. As shown in Figures 12 and 13, the current efficiency (Current Efficiency) of the quantum dot light-emitting diode with the light regulation layer 5 shown in Figure 10 is about the same as the quantum dot light emitting diode without the light regulation layer 5 shown in Figure 2.
  • the external quantum efficiency (External Quantum Efficiency, referred to as EQE) of the quantum dot light-emitting diode with the light regulation layer 5 shown in Figure 10 is about the same as that of the quantum dot without the light regulation layer 5 shown in Figure 2. 7 times that of the diode; that is to say, under the same voltage, the luminous intensity of the quantum dot light-emitting diode with the light regulation layer 5 shown in Figure 10 is higher than that of the quantum dot without the light regulation layer 5 shown in Figure 2 The luminous intensity of the diode is high.
  • ⁇ is the electron-hole equilibrium constant
  • eta rc is the luminous efficiency of the quantum dot light-emitting layer 3
  • eta out is the light extraction efficiency of the quantum dot light-emitting diode.
  • the electron-hole balance constant of the quantum dot light-emitting diode shown in Figure 2 and Figure 10 has an approximate value. equal.
  • the quantum dot light-emitting layer 3 of the same material and the same thickness is used in Figure 2 and Figure 10
  • the luminous efficiency of the quantum dot light-emitting layer 3 in Figure 2 and Figure 10 is equal. Therefore, the difference in the external quantum efficiency of the quantum dot light-emitting diodes shown in FIG. 2 and FIG.
  • the dual microcavity structure shown in Figure 10 the light control layer 5 and the reflective electrode
  • the formation of a microcavity structure between the semi-transmissive semi-reflective electrode and the reflective electrode can effectively improve the light extraction efficiency of the quantum dot light-emitting diode.
  • the microcavity structure formed by the light control layer 5 and the reflective electrode has a negative impact on the light extraction efficiency of the quantum dot light-emitting diode.
  • the amount of improvement is less than the decrease in the light extraction efficiency of the quantum dot light-emitting diode caused by the weakening of the microcavity effect between the semi-transparent counter electrode and the reflective electrode after the addition of the light control layer 5, making the actual light extraction efficiency of the quantum dot light-emitting diode Shows a decline.
  • the microcavity effect between the semi-transparent counter electrode and the reflective electrode is weakened after adding the light control layer 5, because the optical path between the semi-transparent counter electrode and the reflective electrode changes after adding the light control layer 5, and This results in the weakening of the microcavity effect between the semi-transparent counter electrode and the reflective electrode.
  • adding the light control layer 5 has the same impact on the microcavity effect between the semi-transparent counter electrode and the reflective electrode; that is to say, in Figures 7, 9, and 10
  • the microcavity structure formed by the light control layer 5 and the reflective electrode improves the light extraction efficiency of the quantum dot light-emitting diode by more than the microcavity effect between the semi-transparent and semi-reflective electrode after adding the light control layer 5.
  • the decrease in light extraction efficiency caused by the weakening of the quantum dot light-emitting diode increases the actual light extraction efficiency of the quantum dot light-emitting diode.
  • the optical path between the semi-transmissive counter electrode and the reflective electrode changes after adding the light control layer 5, causing a slight gap between the semi-transmissive counter electrode and the reflective electrode.
  • the cavity effect is enhanced.
  • the light emission peak of the quantum dot light-emitting diode shown in Figure 2 is near 458nm
  • the light emission peak of the quantum dot light-emitting diode shown in Figure 7 is near 450nm
  • the light emission peak of the quantum dot light-emitting diode shown in Figure 10 is near 465nm. Taking the light emission peak position of the quantum dot light-emitting diode shown in Figure 2 as a benchmark, the light emission peak position of the quantum dot light-emitting diode shown in Figures 7, 9 and 10 drifts, and the drift amount is less than 10 nm.
  • adding the light control layer 5 can cause a certain degree of peak position blue shift of the quantum dot light-emitting diode.
  • the quantum dot diode is applied to the display panel At medium time, the color gamut of full-color display can be improved to a certain extent.
  • the light output half-peak width of the quantum dot light-emitting diodes shown in Figures 7, 9 and 10 is narrowed, which is also conducive to improving the color gamut of full-color display.
  • the simulation results shown in Figure 11 do not indicate that the light regulation layer 5 in the present disclosure cannot be disposed between the hole injection layer 8 and the hole transport layer 7, but indicate that the first electrode 1 is
  • the reflective electrode has a thickness of 100nm
  • the metal oxide electrode 9 has a thickness of 8nm
  • the hole transport layer 7 has a thickness of 24.5nm
  • the hole injection layer 8 has a thickness of 26.8nm
  • the quantum dot light-emitting layer 3 has a thickness of 14.1nm.
  • the light control layer 5 prepared from a metal material and with a thickness of 3nm is placed between the hole injection layer 8 and the hole transport layer. Between layer 7, the light intensity of the quantum dot light-emitting diode cannot be increased.
  • certain dielectric layers including but not limited to hole injection layer 8, hole transport layer 7, light regulation layer 5, quantum The thickness and/or refractive index of the point light-emitting layer 3 and the electron transport layer 4) are adjusted (for example, the thickness of the light control layer 5 is adjusted, the refractive index of the light control layer 5 is adjusted, the thickness of the hole transport layer 7 is adjusted, the holes are adjusted The refractive index of the transmission layer 7, etc.), so that the light intensity of the quantum dot light-emitting diode can be improved after the light regulation layer 5 is placed between the hole injection layer 8 and the hole transport layer 7.
  • the luminous efficiency of the quantum dot light-emitting layer 3 is low due to the unbalanced carrier transmission rate; for example, the hole transmission rate is significantly greater than the electron transmission rate (generally It is called a "multi-hole system”), or the electron transfer rate is significantly greater than the hole transfer rate (generally called a "multi-electron system”).
  • a semiconductor material with an electron transmission rate greater than the hole transmission rate can be selected to prepare the light control layer 5, and the light control layer 5 is disposed on Between the anode and the quantum dot light-emitting layer 3, it serves as a hole blocking layer.
  • At least one light regulation layer 5 includes: a first light regulation layer 5 , the material of the first light regulation layer 5 includes a semiconductor material; the first light regulation layer 5 is located between the anode and the quantum dot light-emitting layer 3 (for example, the situations shown in Figures 3, 7, and 8), the absolute value of the difference between the HOMO energy level of the first light regulation layer 5 and the HOMO energy level of the hole transport layer 7 is greater than 1 eV, and the first light The control layer 5 is multiplexed as a hole blocking layer.
  • a semiconductor material with a hole transmission rate greater than the electron transmission rate can be selected to prepare the light control layer 5, and the light control layer 5 is disposed on the cathode and the quantum dot light-emitting layer 3 to multiplex as an electron blocking layer.
  • at least one light regulation layer 5 includes: a second light regulation layer 5 , and the material of the second light regulation layer 5 includes a semiconductor material; the second light regulation layer 5 is located between the cathode and the quantum dot light-emitting layer.
  • the absolute value of the difference between the HOMO energy level of the second light regulation layer 5 and the HOMO energy level of the hole transport layer 7 is less than 0.5 eV, and the second light regulation layer
  • the absolute value of the difference between the LUMO energy level of 5 and the LUMO energy level of the hole transport layer 7 is greater than 1 eV, and the first light regulation layer 5 is reused as a hole blocking layer.
  • At least part of the surface of the light regulation layer 5 away from the quantum dot light-emitting layer 3 has a convex or concave shape; and/or, the light regulation layer 5 is close to the quantum dot light-emitting layer 3 At least part of the surface of one side has a convex or concave shape.
  • the first electrode 1 serves as an anode and the second electrode 2 serves as a cathode
  • the first electrode 1 serves as a transparent electrode
  • the second electrode 2 serves as a reflective electrode.
  • the quantum dot light-emitting diode is a positive bottom-emitting type.
  • the material of the first electrode 1 can be a metal oxide material
  • the material of the second electrode 2 can be a metal material.
  • FIG. 14 is a schematic cross-sectional view of yet another quantum dot light-emitting diode provided by an embodiment of the present disclosure.
  • the first electrode 1 serves as the cathode and the second electrode 2 serves as the anode in the quantum dot light-emitting diode shown in Figure 14.
  • the electron transport layer 4 is located on the side of the quantum dot light-emitting layer 3 close to the base substrate 6
  • the hole transport layer 7 and the hole injection layer 8 are located on the side of the quantum dot light-emitting layer 3 away from the base substrate 6 .
  • the first electrode 1 in Figure 14 is a reflective electrode
  • the second electrode 2 is a transparent electrode or a semi-transparent and semi-counter electrode, that is, the quantum dot light-emitting diode is an inverted top-emitting quantum dot diode.
  • the first electrode 1 in FIG. 14 is a transparent electrode
  • the second electrode 2 is a reflective electrode, that is, the quantum dot light-emitting diode is an inverted bottom-emitting quantum dot diode.
  • FIG. 14 only illustrates the case where the quantum dot light-emitting diode includes a light control layer 5 and the light control layer 5 is located between the first electrode 1 and the quantum dot light-emitting layer 3. In this case, it only serves It serves as an example and does not limit the technical solution of the present disclosure.
  • the quantum dot light-emitting diode may be a positive top-emitting quantum dot light-emitting diode, a positive bottom-emitting quantum dot light-emitting diode, an inverted top-emitting quantum dot light-emitting diode, or an inverted bottom-emitting quantum dot light-emitting diode. Any situation.
  • the number of light control layers 5 provided in the quantum dot light-emitting diode is not limited, such as one layer, two layers, or multiple layers; at the same time, the location of the light control layer 5 is not limited, and can be located between the first electrode 1 and the second electrode At any position between 2, it is only necessary to ensure that the light control layer 5 is not adjacent to the reflective electrode.
  • the quantum dot light-emitting diode is a top-emission quantum dot light-emitting diode (the first electrode 1 is a reflective electrode, and the second electrode 2 is a transparent electrode or a semi-transparent semi-reverse electrode), the second electrode 2 can be positioned far away from the substrate.
  • a light-extraction layer (Capping Layer) is provided on one side to improve the light extraction efficiency of the quantum dot light-emitting diode; no corresponding drawing is given in this case.
  • FIG. 15 is a flow chart of a method for preparing a quantum dot light-emitting diode according to an embodiment of the present disclosure. As shown in Figure 15, the preparation method includes:
  • Step S0 forming a first electrode, a second electrode, a quantum dot light-emitting layer and at least one light control layer.
  • the quantum dot light-emitting layer is located between the first electrode and the second electrode.
  • One of the first electrode and the second electrode is a reflective electrode, and the other is a transmissive electrode or a semi-transparent and semi-reverse electrode.
  • the light control layer is located on the first electrode. Between the quantum dot light-emitting diode and the second electrode, the light control layer is configured to form a microcavity structure with the reflective electrode, so that the light extraction efficiency P of the quantum dot light-emitting diode satisfies: 25% ⁇ P ⁇ 98%.
  • the light control layer is prepared through an evaporation process, a spin coating process or a printing process.
  • the specific process for preparing the light control layer can be selected according to the material of the light control layer, which is not limited by this disclosure.
  • the light control layer can be formed by spin-coating nanosheet materials. Such nanosheets can effectively enhance the light extraction performance of the light control layer in the vertical direction.
  • step S0 also includes forming an electron injection layer, forming a hole injection layer, and forming a hole transport layer. layers and other steps.
  • embodiments of the present disclosure also provide a display panel, which includes the quantum dot light-emitting diode provided in any of the previous embodiments.
  • the quantum dot light-emitting diode can be prepared using the preparation method provided above.
  • the quantum dot light-emitting diode in the display panel and its preparation method please refer to the corresponding content in the previous embodiments, and will not be described again here.
  • the display panel in order to achieve color display of the display panel, includes: a first quantum dot light-emitting diode that emits blue light and a second quantum dot light-emitting diode that emits light of other colors. At least the first quantum dot light-emitting diode is the The quantum dot light-emitting diode; the number of microcavity structures in the first quantum dot light-emitting diode is greater than the number of microcavity structures in the second quantum dot light-emitting diode.
  • the above-mentioned other color lights may specifically be at least one of red light, green light, cyan light, magenta light and yellow light.
  • the display panel includes a blue quantum dot light emitting diode (a first quantum dot light emitting diode) that emits blue light, a red light quantum dot light emitting diode that emits red light (a second quantum dot light emitting diode), a green light emitting diode. Green quantum dot light-emitting diode (a second quantum dot light-emitting diode).
  • the light control layer can be provided only in the blue quantum dot light-emitting diode, and no layer is provided in the red light quantum dot light-emitting diode and the green light quantum dot light-emitting diode, so that the number of microcavity structures in the blue light quantum dot light-emitting diode is more than that of the red light quantum dot light-emitting diode.
  • the number of microcavity structures in point light-emitting diodes and green quantum dot light-emitting diodes; or, the light control layer is provided in blue light quantum dot light-emitting diodes, red light quantum dot light-emitting diodes and green light quantum dot light-emitting diodes, but in blue light quantum dot light-emitting diodes
  • the number of light regulation layers is greater than the number of light regulation layers in the red quantum dot light emitting diode and the green light quantum dot light emitting diode.
  • the blue quantum dot light-emitting diode it is preferable to provide a light control layer in the blue quantum dot light-emitting diode. This is because experimental simulations show that after the above-mentioned light control layer is provided in the blue quantum dot light-emitting diode, the light of the blue quantum dot light-emitting diode will be extracted. The efficiency can be significantly improved, and the light extraction rate of quantum dot light-emitting diodes can reach a level of ⁇ 25%.
  • the display panel provided by the embodiments of the present disclosure can be applied to a display device, and the display device can be any product or component with a display function, such as a television, a digital camera, a mobile phone, a tablet computer, etc.

Abstract

本公开提供了一种量子点发光二极管，其中，包括：第一电极、第二电极、设置在所述第一电极与所述第二电极之间的量子点发光层，所述第一电极和所述第二电极中之一为反射电极，另一为透射电极或半透半反电极；在所述第一电极与所述第二电极之间设置有至少一层光调控层，所述光调控层配置为与所述反射电极构成微腔结构，使所述量子点发光二极管的光取出效率P满足：25％≤P≤98％。本公开实施例还提供了一种量子点发光二极管的制备方法和显示面板。

Description

量子点发光二极管及其制备方法和显示面板 技术领域
本公开涉及显示领域，特别涉及一种量子点发光二极管及其制备方法和显示面板。
背景技术
量子点发光二极管(Quantum Dot Light Emitting Diodes，简称QLED)通常包括阴极、阳极和具有多个量子点纳米晶体的量子点发光层，量子点发光层夹在阴极和阳极之间。通过将电场施加到量子点发光二极管，使电子和空穴移动到量子点发光层中，发量子点光层中的电子和空穴被捕获在量子点中并被重新组合，发射光子。与有机发光二极管相比，量子点发光二极管的发射光谱更窄。然而，现有的量子点发光二极管的光取出效率普遍偏低，发光强度(Emission Intensity)难以作进一步提升。
发明内容
本公开旨在至少解决现有技术中存在的技术问题之一，提出了一种量子点发光二极管及其制备方法和显示面板。
第一方面，本公开实施例提供了一种量子点发光二极管，其中，包括：第一电极、第二电极、设置在所述第一电极与所述第二电极之间的量子点发光层，所述第一电极和所述第二电极中之一为反射电极，另一为透射电极或半透半反电极；
在所述第一电极与所述第二电极之间设置有至少一层光调控层，所述光调控层配置为与所述反射电极构成微腔结构，使所述量子点发光二极管的光取出效率P满足：25％≤P≤98％。
在一些实施例中，所述光调控层的透过率Q满足：70％≤Q＜100％；
所述光调控层的反射率R满足：0＜R≤30％。
在一些实施例中，所述光调控层的厚度包括：1nm～35nm。
在一些实施例中，所述光调控层的折射率包括：0.1～0.3。
在一些实施例中，所述光调控层的材料包括半导体材料或金属材料。
在一些实施例中，所述光调控层的材料包括所述金属材料，所述光调控层与所述量子点发光层不直接接触。
在一些实施例中，所述光调控层与所述反射电极之间存在至少一层功能介质层且满足：
Figure PCTCN2022088688-appb-000001
φ 1表示光线在所述反射电极上发生反射所产生的相移，φ 2表示光线在所述光调控层上发生反射所产生的相移，k表示位于所述光调控层与所述反射电极之间的所述功能介质层的数量，n i和d i分别表示靠近所述反射电极的第i层所述功能介质层的折射率和厚度，m 1为预先配置的正整数，λ表示量子点发光层的发光峰值波长，i为整数且1≤i≤k。
在一些实施例中，所述第一电极和所述第二电极中之一为反射电极，另一为半透半反电极；
位于所述半透半反电极与所述反射电极之间的功能介质层满足：
Figure PCTCN2022088688-appb-000002
φ 3表示光线在所述半透半反电极上发生反射所产生的相移，s表示位于所述半透半反电极与所述反射电极之间的所述功能介质层的数量，n j和d j分别表示靠近所述反射电极的第j层所述功能介质层的折射率和厚度，m 2为预先配置的正整数且m 2＞m 1，j为整数且1≤j≤s。
在一些实施例中，所述第一电极与所述第二电极中之一作为所述量 子点发光二极管的阴极，另一作为所述量子点发光二极管的阳极；
所述阴极与所述量子点发光层之间设置有电子传输层；
所述阳极与所述量子点发光层之间设置有空穴注入层和空穴传输层。
在一些实施例中，所述至少一层光调控层包括：第一光调控层，所述第一光调控层的材料包括半导体材料；
所述第一光调控层位于所述阳极与所述量子点发光层之间，所述第一光调控层的HOMO能级与所述空穴传输层的HOMO能级的差的绝对值大于1eV。
在一些实施例中，所述至少一层光调控层包括：第二光调控层，所述第二光调控层的材料包括半导体材料；
所述第二光调控层位于所述阴极与所述量子点发光层之间，所述第二光调控层的HOMO能级与所述空穴传输层的HOMO能级的差的绝对值小于0.5eV，所述第二光调控层的LUMO能级与所述空穴传输层的LUMO能级的差的绝对值大于1eV。
在一些实施例中，所述光调控层远离所述量子点发光层的一侧表面上的至少部分区域呈外凸形貌或内凹形貌；
和/或，所述光调控层靠近所述量子点发光层的一侧表面上的至少部分区域呈外凸形貌或内凹形貌。
在一些实施例中，还包括：衬底基板，所述第一电极位于所述衬底基板上，所述第二电极位于所述第一电极远离所述衬底基板的一侧；
所述第一电极为反射电极，所述第二电极为半透半反电极；
或者，所述第一电极为透射电极，所述第二电极为反射电极。
在一些实施例中，所述反射电极作为所述量子点发光二极管的阳极，所述反射电极的材料包括金属材料；
在所述反射电极靠近所述量子点发光层的一侧设置有与所述反射电 极相邻的金属氧化物电极。
第二方面，本公开实施例还提供了一种显示面板，其中，包括：如上述第一方面中提供的所述量子点发光二极管。
所述显示面板包括：发出蓝色光的第一量子点发光二极管和发出其他颜色光的第二量子点发光二极管，至少所述第一量子点发光二极管为所述量子点发光二极管；
所述第一量子点发光二极管中微腔结构的数量多于所述第二量子点发光二极管中微腔结构的数量。
第三方面，本公开实施例还提供了一种用于制备第一方面中所述量子点发光二极管的制备方法，包括：
形成第一电极、第二电极、量子点发光层和至少一层光调控层，所述量子点发光层位于所述第一电极与所述第二电极之间，所述第一电极和所述第二电极中之一为反射电极，另一为透射电极或半透半反电极，所述光调控层位于所述第一电极与所述第二电极之间，所述光调控层配置为与所述反射电极构成微腔结构，使所述量子点发光二极管的光取出效率P满足：25％≤P≤98％。
在一些实施例中，所述光调控层通过蒸镀工艺、旋涂工艺或打印工艺进行制备。
附图说明
图1为本公开实施例提供的一种量子点发光二极管的截面示意图；
图2为本公开实施例中未设置光调控层的一种量子点发光二极管的截面示意图；
图3为在图2所示量子点发光二极管内位于空穴传输层与量子点发光层之间设置一层光调控层的截面示意图；
图4为模拟出的图2和图3所示量子点发光二极管的发光光谱图；
图5为模拟出的图3中所示量子点发光二极管内光调控层处于不同厚度情况下的发光光谱图；
图6为模拟出的图3中所示量子点发光二极管内光调控层处于不同折射率情况下的发光光谱图；
图7～图10为本公开实施例中光调控层位于量子点发光二极管内不同位置的截面示意图；
图11为模拟出的图2、图7～图10所示量子点发光二极管的发光光谱图；
图12为图2和图10所示量子点发光二极管的发光亮度-电流效率关系图；
图13为图2和图10所示量子点发光二极管的发光亮度-外量子效率关系图；
图14为本公开实施例提供的再一种量子点发光二极管的截面示意图；
图15为本公开实施例提供的一种量子点发光二极管的制备方法的流程图。
具体实施方式
为使本领域的技术人员更好地理解本公开的技术方案，下面结合附图对本公开提供的一种量子点发光二极管及其制备方法和显示面板进行详细描述。
如本文中使用的“约”或“大约”包括所陈述的值且意味着在如由本领域普通技术人员考虑到所讨论的测量和与具体量的测量有关的误差(即，测量系统的限制)而确定的对于具体值的可接受的偏差范围内。例如，“约”可意味着相对于所陈述的值的差异在一种或多种标准偏差范围内，或者在±30％、20％、10％、5％范围内。
下文中，最高占据分子轨道(“HOMO”)能级或最低未占分子轨道(LUMO)能级是作为来自真空的绝对值表示的。此外，当HOMO能级或LUMO能级被称为‘深的’、‘高的’、或‘大的’时，所述HOMO能级或LUMO能级具有大的相对于‘0eV’即真空能级的绝对值，而当HOMO能级或LUMO能级被称为‘浅的’、‘低的’、或‘小的’时，所述HOMO能级或LUMO能级具有小的距离‘0eV’即真空能级的绝对值。
图1为本公开实施例提供的一种量子点发光二极管的截面示意图。如图1所示，该量子点发光二极管包括：第一电极1、第二电极2、设置在第一电极1与第二电极2之间的量子点发光层3，第一电极1和第二电极2中之一为反射电极，另一为透射电极或半透半反电极；在第一电极1与第二电极2之间设置有至少一层光调控层5，光调控层5配置为与所述反射电极构成微腔结构，使所述量子点发光二极管的光取出效率P满足：25％≤P≤98％。
其中，第一电极1和第二电极2中之一作为量子点发光二极管的阳极，另一作为量子点发光二极管的阴极。通过向第一电极1和第二电极2施加不同电压以形成电场，从而能够驱动量子点发光层3发光。
在本公开实施例中，在本公开实施例中，微腔结构能够有效提升量子点发光二极管的光取出效率。量子点发光二极管的光取出效率等于量子点发光二极管的实际出光量(本公开用量子点发光二极管的发光强度来表示)与量子点发光层3的出光量(本公开用量子点发光层3的发光强度来表示)的比值。
本公开的技术方案通过在第一电极1与第二电极2之间设置至少一层光调控层5，且光调控层5与反射电极形成微腔结构，基于该微腔结构的微腔效应可使得量子点发光二极管的光取出效率得到提升，有利于提升量子点发光二极管的发光强度。在本公开实施例中，光调控层5具体为具有半透半反特性的功能膜层。
当器件的发光区位于一个反射膜(即本公开中的反射电极)和半透半反射膜(即本公开中的光调控层5)构成的谐振腔内，腔长与光波的波长在同一数量级时，特定波长的光会得到选择和加强，光谱发生窄化，此为微腔效应。
需要说明的是，在图1所示情况中仅示例性画出了在第一电极1与第二电极2之间设置有一层光调控层5的情况，该情况仅起到示例性作用，其不会对本公开的技术方案产生限制。
另外，为使得光调控层5能够与反射电极形成微腔结构，则需保证在光调控层5与反射电极之间存在至少一层功能介质层；也就是说，光调控层5与反射电极不相邻。在图1所示情况中，第一电极1作为反射电极、第二电极2作为透明电极或半透半反电极，为使得光调控层5与反射电极(第一电极1)不相邻，则需将光调控层5设置于量子点发光层3与第二电极2之间，此时，光调控层5与反射电极之间存在一层功能介质层：量子点发光层3。
当然，在图1所示情况中还可以在该光调控层5与第二电极2/量子点发光层3之间设置其他光调控层5，以实现位于第一电极1与第二电极2之间的光调控层5数量大于或等于2，且每个光调控层5均能够与反射电极形成能够用于提升量子点发光二极管的光取出效率的微腔结构。此种情况未给出相应附图。
在一些实施例中，光调控层5与反射电极之间存在至少一层功能介质层且满足：
Figure PCTCN2022088688-appb-000003
φ 1表示光线在反射电极上发生反射所产生的相移，φ 2表示光线在光调控层5上发生反射所产生的相移，k表示位于光调控层5与反射电极之间的功能介质层的数量，n i和d i分别表示靠近反射电极的第i层功能介 质层的折射率和厚度，m 1为预先配置的正整数(m 1表示光调控层5与反射电极所形成微腔的模数)，λ表示量子点发光层3的发光峰值波长，i为整数且1≤i≤k。
在图1所示情况中，光调控层5与反射电极之间仅存在一层功能介质层：量子点发光层3，即k取值为1。
通过满足上述式(1)，可使得光调控层5与反射电极所形成的微腔结构能够实现较强的微腔效应。
在一些实施例中，第一电极1和第二电极2中之一为反射电极，另一为半透半反电极(例如图1中第一电极1为反射电极，第二电极2为半透半反电极)，位于半透半反电极与反射电极之间的功能介质层满足：
Figure PCTCN2022088688-appb-000004
φ 3表示光线在半透半反电极上发生反射所产生的相移，s表示位于半透半反电极与反射电极之间的功能介质层的数量，n j和d j分别表示靠近反射电极的第j层功能介质层的折射率和厚度，m 2为预先配置的正整数(m 2表示半透半反电极与反射电极所形成微腔的模数)且m 2＞m 1，j为整数且1≤j≤s。
也就是说，不仅光调控层5能够与反射电极形成提升量子点发光二极管的出光量的微腔结构，半透半反电极也能够与反射电极形成提升量子点发光二极管的出光量的微腔结构。此时，在图1所示情况中，存在两个能够提升量子点发光二极管的出光量的微腔结构，有利于进一步提升量子点发光二极管的光取出效率和发光强度。
在图1所示情况中，半透半反电极(第二电极2)与反射电极(第一电极1)之间存在两层功能介质层：量子点发光层3和光调控层5，即s取值为2。
通过满足上述式(2)，可使得半透半反电极与反射电极所形成的微 腔结构能够实现较强的微腔效应。
在本公开实施例中，m 1和m 2的具体取值可根据实际需要来进行设定。例如，在仅设置有1层光调控层5时，m 1＝1且m 2＝2,或者m 1＝1且m 2＝3，或者m 1＝2且m 2＝3；在设置有至少2层光调控层5时，各光调控层5与反射电极所形成微腔所对应的模数取值均不相同，且半透半反电极与反射电极所形成微腔的模数大于任意一层光调控层5与反射电极所形成微腔所对应的模数。在实际应用中，为避免量子点发光二极管的厚度过大，一般会将光调控层5/半透半反电极与反射电极所形成微腔的模数设计的较小。
在一些实施例中，光调控层5的透过率为Q，光调控层5的反射率R为1-Q，其中Q和R分别满足：70％≤Q＜100％，0＜R≤30％。
在一些实施例中，光调控层5的厚度包括：1nm～35nm。需要说明的是，本公开中范围A～B的表述方式中，限定的范围包括A和B两个端点值。
在一些实施例中，光调控层5的折射率包括：0.1～0.3。
在一些实施例中，光调控层5的材料包括半导体材料或金属材料(例如金、银、铜、铝、镁、锂等)。
进一步可选地，在光调控层5为金属材料时，光调控层5与量子点发光层3不直接接触，以避免量子点发光层3中的量子点发生淬灭，而使得量子点发光层3的发光强度降低，不利于量子点发光二极管的出光量的提升。另外，在光调控层5的材料为金属材料时，光调控层5的厚度为1nm～10nm，以保证其透过率70％≤Q＜100％。
需要说明的是，在一些情况中，即便将由金属材料制成的光调控层5与量子点发光层3相邻设置可能会使得量子点发光层3的出光量降低，但是，由于光调控层5的存在形成了微腔效应，相比于未设置光调控层5的量子点发光二极管，仍可在一定程度上提升量子点发光二极管的整 体出光效率。具体情况可参见后面的示例。
在光调控层5的材料为半导体材料时，对于光调控层5的设置位置，原则上不作限定。
下面将继续结合一些示例来对本公开的技术方案进行详细描述。
图2为本公开实施例中未设置光调控层的一种量子点发光二极管的截面示意图。图3为在图2所示量子点发光二极管内位于空穴传输层7与量子点发光层3之间设置一层光调控层的截面示意图。如图2和图3所示，在一些实施例中，为提升注入至量子点发光层3内载流子(包括电子和空穴)的数量，在阴极与量子点发光层3之间设置有电子传输层4(Electron Transport Layer，简称ETL)，阳极与量子点发光层3之间设置有空穴注入层8(Hole Injection Layer，简称HIL)和空穴传输层7(Hole Transport Layer，简称HTL)。
在一些实施例中，量子点发光二极管还包括衬底基板6，第二电极2位于第一电极1远离衬底基板6的一侧。
在图2和图3所示情况中，以第一电极1作为阳极、第二电极2作为阴极，且第一电极1为反射电极，第二电极2为半透半反电极或透明电极的情况为例；此时，量子点发光二极管为正置顶发射型量子点发光二极管。在将顶发射型量子点发光二极管应用至显示面板中时，由于用于驱动量子点发光二极管的薄膜晶体管(TFT)阵列是位于量子点发光二极管的非出光侧，故薄膜晶体管阵列不会对量子点发光二极管的出光造成遮挡，因此量子点发光二极管的出光面积可设计的相对较大，有利于提升像素开口率。
在一些实施例中，反射电极的材料包括金属材料。为实现功函数匹配(也可以看作是费米能级匹配)，在由金属材料所制成的反射电极靠近量子点发光层3的一侧设置有与反射电极相邻的金属氧化物电极9，金属氧化物电极9的材料为透明且导电的金属氧化物材料。
参见图2和图3所示，第一电极1(反射电极)的材料包括具有高的功函数的金属材料，包括但不限于镍、铂、钒、铬、铜、锌、金中至少之一。为尽可能达到全反射效果(反射率为100％或接近100％)以及保证良好的导电性，其厚度可设计的相对厚一些。可选地，作为反射电极的第一电极1的厚度为70nm～150nm，例如100nm。
金属氧化物电极9的材料包括但不限于金属氧化物，具体可以包括氧化锌(ZnO)、氧化铟(InO)、氧化锡(SnO)、氧化铟锡(ITO)、氧化铟锌(IZO)、或氟掺杂氧化锡(FTO)中至少之一。金属氧化物电极9主要起到功函数匹配的作用，其厚度可设计的相对薄一些。可选地，金属氧化物电极9的厚度为5nm～12nm，例如8nm。
空穴注入层8的材料包括但不限于聚(3,4-亚乙二氧基噻吩)聚苯乙烯磺酸盐(PEDOT：PSS)、聚噻吩、聚苯胺、聚吡咯、铜酞菁。
空穴传输层7的材料包括但不限于p型聚合物材料和各种p型低分子量材料，例如，聚噻吩、聚苯胺、聚吡咯、具有聚-3,4-亚乙基二氧噻吩和聚(对苯乙烯磺酸钠)、4,4’-亚环己基双[N,N-双(4-甲基苯基)苯胺(TAPC)或者4,4’,4”-三(N-咔唑基)三苯胺(TCTA),N,N'-二(1-萘基)-N,N'-二苯基联苯胺(NPB)的混合物。
空穴注入层8和空穴传输层7的厚度是根据所需要的空穴传输速率来设定。可选地，空穴注入层8的厚度包括20nm～30nm，例如24.5nm；空穴传输层7的厚度包括20nm～30nm，例如26.8nm。
量子点发光层3的材料包括但不限于无镉(Cd)量子点材料或蓝光含镉量子点材料；其中，无镉量子点材料可以为磷化铟(InP)量子点或InP衍生的核壳结构量子点，例如InP/ZnSe/ZnS，InP/ZnSeS/ZnS；蓝光含镉量子点材料可以为CdS/ZnSe/ZnS,CdSe/ZnSe/ZnS,CdInS/ZnSe/ZnS。当然，量子点发光层3的材料还可以采用其他量子点，例如GaP/ZnSe，CsPbBr3/ZnS等量子点。 可选地，量子点发光层3的厚度为10nm～20nm，例如14.1nm。
电子传输层4的材料包括但不限于氧化锌(ZnO)、氧化镁锌(ZnMgO)、氧化铝锌(AZO)和氧化镁铝锌中的至少一种。可选地，电子传输层4的厚度包括5nm～20nm，例如8.9nm。
第二电极2可以为透明电极或半透半反电极。其中，当第二电极2为透明电极时，第二电极2的材料可采用导电的金属氧化物材料，具体可以包括氧化锌、氧化铟、氧化锡、氧化铟锡、氧化铟锌中至少之一；此时，为保证第二电极2的导电效果，由金属氧化物材料所形成的透明电极的厚度大于30nm，例如70nm。当第二电极2为半透半反电极时，第二电极2可采用具有比第一电极1功能函数更低的金属材料，包括但不限于铝、镁、钙、钠、钾、钛、铟、钇、锂、钆、银、锡、铅、铯、钡中至少之一；此时，为保证第二电极2具有一定的导电性以及呈现半透半反效果，其厚度不能设置过厚或过薄，可选地，由金属材料所形成的半透半反电极的厚度为1nm～15nm，例如10nm。
图4为依据图2和图3所示量子点发光二极管的发光光谱图。如图4所示，在图2和图3中，第一电极1(反射电极)的厚度为100nm，金属氧化物电极9的厚度为8nm，空穴传输层7的厚度为24.5nm，空穴注入层8的厚度为26.8nm，量子点发光层3的厚度为14.1nm，量子点发光层的材料为能够发出蓝色光的量子点材料，电子传输层4的厚度为8.9nm，第二电极2为半透半反电极且厚度为10nm。在图4中，以图3所示半透半反介质的材料为半导体材料(折射率约为0.2)且厚度为10nm的情况进行模拟。
通过图4所示模拟结果来看，相较于图2中未设置光调控层5的情况，图3中所示在空穴传输层7与量子点发光层3之间设置光调控层5的方案可有效提升量子点发光二极管的发光强度。具体地，相较于图2中所示单个微腔结构(半透半反电极与反射电极之间形成微腔结构)， 图4中所示双重微腔结构(光调控层5与反射电极之间形成微腔结构、半透半反电极与反射电极之间形成微腔结构)，其出光强度提升了约32％，半峰宽由优化前的39nm缩窄为27nm。其中，半峰宽的缩窄，即表示量子点发光二极管所发出的光的颜色越纯净，在将其应用至显示面板上时，有利于提升显示面板的色域。
需要说明的是，本公开实施例中以发出蓝色光的量子点发光二极管进行了模拟，以验证设置光调控层5后可对量子点发光二极管的光取出效率进行提升，该情况仅到示例性作用，其不会对本公开的技术方案产生限制。本公开的技术方案还可以适用于发出其他颜色光的量子点发光二极管，例如发出红色光的红光量子点二极管和发出绿色光的绿光量子点二极管。
图5为模拟出的图3中所示量子点发光二极管内光调控层处于不同厚度情况下的发光光谱图。如图5所示，以图3中光调控层5采用半导体材料且折射率约为0.2为前提，对不同厚度的光调控层5的情况分别进行了模拟，通过图5所示模拟结果可见，当图3所示量子点发光二极管内光调控层5的厚度在5nm～35nm时，该量子点发光二极管的出光强度相较于图2中所示量子点发光二极管的出光强度有所提升。
图6为模拟出的图3中所示量子点发光二极管内光调控层处于不同折射率情况下的发光光谱图。如图6所示，以图3中光调控层5采用半导体材料且厚度为10nm为前提，对不同折射率的光调控层5的情况分别进行了模拟，通过图6所示模拟结果可见，当图3所示量子点发光二极管内光调控层5的折射率在0.1～0.3时，该量子点发光二极管的出光强度相较于图2中所示量子点发光二极管的出光强度有所提升。
当然，基于前面式(1)和式(2)可见，在增设光调控层5时为实现较佳的微腔效应，需综合考虑到位于第一电极1与第二电极2之间其他各介质层的厚度、折射率。
本公开还对光调控层5采用金属材料且位于其他位置的情况进行模拟。图7～图10为本公开实施例中光调控层5位于量子点发光二极管内不同位置的截面示意图。如图7至图10所示，在图7所示情况中，光调控层5位于金属氧化物电极9与空穴注入层8之间；在图8所示情况中，光调控层5位于空穴注入层8与空穴传输层7之间；在图9所示情况中，光调控层5位于量子点发光层3与电子传输层4之间；在图10所示情况中，光调控层5位于电子传输层4与第二电极2之间。
图11为模拟出的图2、图7～图10所示量子点发光二极管的发光光谱图。如图11所示，在图7至图10中，第一电极1(反射电极)的厚度为100nm，金属氧化物电极9的厚度为8nm，空穴传输层7的厚度为24.5nm，空穴注入层8的厚度为26.8nm，量子点发光层3的厚度为14.1nm，电子传输层4的厚度为8.9nm，第二电极2为半透半反电极且厚度为10nm；在图7至图10中，光调控层5采用金属材料且厚度为3nm。
通过图11所示模拟结果来看，相较于图2中未设置光调控层5的情况，图7中所示在金属氧化物电极9与空穴注入层8之间设置光调控层5、图9中所示在量子点发光层3与电子传输层4之间设置光调控层5、图10中所示在电子传输层4与第二电极2之间设置光调控层5，该三种方案均可有效提升量子点发光二极管的发光强度。
图12为图2和图10所示量子点发光二极管的发光亮度-电流效率关系图。图13为图2和图10所示量子点发光二极管的发光亮度-外量子效率关系图。如图12和图13所示，图10中所示设置有光调控层5的量子点发光二极管的电流效率(Current Efficiency)约为图2中所示未设置有光调控层5的量子点发光二极管的2倍；图10所示设置有光调控层5的量子点发光二极管的外量子效率(External Quantum Efficiency,简称EQE)约为图2中所示未设置有光调控层5的量子点发光二极管的7倍；也就是说，在相同的电压下，图10所示设置有光调控层5的量子点 发光二极管的发光强度比图2中所示未设置有光调控层5的量子点发光二极管的发光强度高。
量子点发光二极管的外量子效率η EQE：
η EQE＝γ×η rc×η out
其中，γ为电子空穴平衡常数，η rc为量子点发光层3的发光效率，η out为量子点发光二极管的光取出效率。
通过预先实验测得光调控层5的增设，不会对量子点发光二极管内部的电子空穴平衡产生很大影响，图2和图10所示量子点发光二极管的电子空穴平衡常数取值近似相等。同时，由于图2和图10中使用相同材料、相同厚度的量子点发光层3，故图2和图10中量子点发光层3的发光效率相等。因此，图2和图10中所示量子点发光二极管的外量子效率的差异，必然是因为图2和图10所示量子点发光二极管的光取出效率的不同所导致。也就是说，相较于图2中所示单个微腔结构(半透半反电极与反射电极之间形成微腔结构)，图10中所示双重微腔结构(光调控层5与反射电极之间形成微腔结构、半透半反电极与反射电极之间形成微腔结构)可以有效提升量子点发光二极管的光取出效率。
此外，再参见图2、图8和图11，在图8所示方案中虽然存在光调控层5，但光调控层5与反射电极所形成微腔结构对量子点发光二极管的光取出效率的提升量，小于增设光调控层5后半透半反电极与反射电极之间的微腔效应减弱而导致量子点发光二极管的光取出效率降低的下降量，使得量子点发光二极管的实际光取出效率呈现下降。其中，增设光调控层5后半透半反电极与反射电极之间的微腔效应减弱，是因为增设光调控层5后半透半反电极与反射电极之间的光程发生了变化，并造成了半透半反电极与反射电极之间的微腔效应减弱。
在图7～图10所示方案中，增设光调控层5后对半透半反电极与反 射电极之间的微腔效应的影响相同；也就是说，在图7、图9、图10所示方案中，光调控层5与反射电极所形成微腔结构对量子点发光二极管的光取出效率的提升量，大于增设光调控层5后半透半反电极与反射电极之间的微腔效应减弱而导致量子点发光二极管的光取出效率降低的下降量，使得量子点发光二极管的实际光取出效率呈现提升。
当然，在一些情况中，也可能会出现在增设光调控层5后半透半反电极与反射电极之间的光程发生了变化，并造成了半透半反电极与反射电极之间的微腔效应增强的情况。
再次参见图11所示，图2所示量子点发光二极管的出光峰位在458nm附近，图7所示量子点发光二极管的出光峰位在450nm附近，图9所示量子点发光二极管的出光峰位在452nm附近，图10所示量子点发光二极管的出光峰位在465nm附近。以图2所示量子点发光二极管的出光峰位作为基准，图7、图9和图10所示量子点发光二极管的出光峰位发生漂移，且漂移量均小于10nm。以量子点发光层3中的量子点为蓝光量子点为例，则增设光调控层5后，可使得量子点发光二极管出现一定程度的峰位蓝移，在将该量子点二极管应用至显示面板中时，可以在一定程度上提升全彩显示的色域。此外，通过图11可见，图7、图9和图10所示量子点发光二极管的出光半峰宽缩窄，也有利于提升全彩显示的色域。
当然，需要说明的是，图11所示模拟结果并不是表明本公开中的光调控层5无法设置在空穴注入层8与空穴传输层7之间，而是表明在第一电极1为反射电极且厚度为100nm，金属氧化物电极9的厚度为8nm，空穴传输层7的厚度为24.5nm，空穴注入层8的厚度为26.8nm，量子点发光层3的厚度为14.1nm，电子传输层4的厚度为8.9nm，第二电极2为半透半反电极且厚度为10nm时，将采用金属材料制备且厚度为3nm光调控层5放置于空穴注入层8与空穴传输层7之间，无法提升量子点 发光二极管的出光强度。但是，在实际应用中，可通过对位于第一电极1和第二电极2之间的某些介质层(包括但不限于空穴注入层8、空穴传输层7、光调控层5、量子点发光层3、电子传输层4)的厚度和/或折射率进行调整(例如调整光调控层5的厚度、调整光调控层5的折射率、调整空穴传输层7的厚度、调整空穴传输层7的折射率等)，以使得将光调控层5放置于空穴注入层8与空穴传输层7之间后量子点发光二极管的出光强度能够得到提升。
在相关技术所涉及的量子点发光二极管中，会出现因载流子传输速率不平衡而导致量子点发光层3的发光效率较低的问题；例如，空穴传输速率明显大于电子传输速率(一般称为“多空穴体系”)，或者电子传输速率明显大于空穴传输速率(一般称为“多电子体系”)。
针对相关技术所涉及“多空穴体系”的问题，在本公开实施例中可选择电子传输速率大于对空穴传输速率的半导体材料来制备光调控层5，且将该光调控层5设置于阳极与量子点发光层3之间，以复用作空穴阻挡层。具体地，在一些实施例中，至少一层光调控层5包括：第一光调控层5，第一光调控层5的材料包括半导体材料；第一光调控层5位于阳极与量子点发光层3之间(例如图3、图7、图8中所示情况)，第一光调控层5的HOMO能级与空穴传输层7的HOMO能级的差的绝对值大于1eV，第一光调控层5复用作空穴阻挡层。
针对相关技术所涉及“多电子体系”的问题，在本公开实施例中可选择空穴传输速率大于对电子传输速率的半导体材料来制备光调控层5，且将该光调控层5设置于阴极与量子点发光层3之间，以复用作电子阻挡层。具体地，在一些实施例中，至少一层光调控层5包括：第二光调控层5，第二光调控层5的材料包括半导体材料；第二光调控层5位于阴极与量子点发光层3之间(例如图9、图10中所示情况)，第二光调控层5的HOMO能级与空穴传输层7的HOMO能级的差的绝对值小于 0.5eV，第二光调控层5的LUMO能级与空穴传输层7的LUMO能级的差的绝对值大于1eV，第一光调控层5复用作空穴阻挡层。
在一些实施例中，光调控层5远离量子点发光层3的一侧表面上的至少部分区域呈外凸形貌或内凹形貌；和/或，光调控层5靠近量子点发光层3的一侧表面上的至少部分区域呈外凸形貌或内凹形貌。通过上述设计，有利于提升光调控层5表面的光取出性能，有利于提升量子点发光二极管的光取出效率。
需要说明的是，在第一电极1作为阳极、第二电极2作为阴极的同时，第一电极1为透明电极，第二电极2为反射电极，此时量子点发光二极管为正置底发射型量子点发光二极管；此时，第一电极1的材料可采用金属氧化物材料，第二电极2的材料可采用金属材料。其中，当第一电极1的材料采用金属氧化物材料(例如ITO)时，则在第一电极1远离衬底基板6一侧无需再设置用于功函数匹配的金属氧化物电极9。
图14为本公开实施例提供的再一种量子点发光二极管的截面示意图。如图14所示，与前面实施例中不同的是，图14所示量子点发光二极管中第一电极1作为阴极、第二电极2作为阳极。此时，电子传输层4位于量子点发光层3靠近衬底基板6的一侧，空穴传输层7和空穴注入层8位于量子点发光层3远离衬底基板6的一侧。
在一些实施例中，图14中第一电极1为反射电极，第二电极2为透明电极或半透半反电极，即该量子点发光二极管为倒置顶发射型量子点二极管。
在另一些实施例中，图14中第一电极1为透明电极，第二电极2为反射电极，即该量子点发光二极管为倒置底发射型量子点二极管。
当然，图14中仅示例性画出了量子点发光二极管包括一层光调控层5且该光调控层5位于第一电极1与量子点发光层3之间的情况，对于该情况仅起到示例性作用，其不会对本公开的技术方案产生限制。
在本公开实施例中，量子点发光二极管可以为正置顶发射型量子点发光二极管、正置底发射型量子点发光二极管、倒置顶发射型量子点发光二极管、倒置底发射型量子点发光二极管中任意情况。量子点发光二极管内所设置的光调控层5的数量不作限定，例如1层、2层或多层；同时，光调控层5的设置位置也不作限定，可位于第一电极1与第二电极2之间任意位置，仅需保证光调控层5与反射电极不相邻即可。
另外，当量子点发光二极管为顶发射型量子点发光二极管(第一电极1为反射电极，第二电极2为透明电极或半透半反电极)时，可在第二电极2远离衬底基板6一侧设置取光层(Capping Layer)，以提升量子点发光二极管的光取出效率；该情况未给出相应附图。
基于同一发明构思，本公开实施例还提供了一种量子点发光二极管的制备方法。图15为本公开实施例提供的一种量子点发光二极管的制备方法的流程图。如图15所示，该制备方法包括：
步骤S0、形成第一电极、第二电极、量子点发光层和至少一层光调控层。
其中，量子点发光层位于第一电极与第二电极之间，第一电极和第二电极中之一为反射电极，另一为透射电极或半透半反电极，光调控层位于第一电极与第二电极之间，光调控层配置为与反射电极构成微腔结构，使量子点发光二极管的光取出效率P满足：25％≤P≤98％。
在一些实施例中，光调控层通过蒸镀工艺、旋涂工艺或打印工艺进行制备。在实际应用中，制备光调控层的具体工艺可根据光调控层的材料来进行选择，本公开不作限定。作为一种可选实施方案，可以通过旋涂纳米片材料来形成光调控层，这种纳米片可以有效增强光调控层在垂直方向的光取出性能。
此外，当量子点发光二极管内设置有电子注入层、空穴注入层、空穴传输层等介质层时，在步骤S0中也相应包括形成电子注入层、形成空 穴注入层、形成空穴传输层等步骤。
基于同一发明构思，本公开实施例还提供了一种显示面板，该显示面板包括前面任一实施例提供的量子点发光二极管，该量子点发光二极管可采用前面所提供的制备方法来进行制备。对于显示面板内量子点发光二极管及其制备方法的具体描述可参见前面实施例中的相应内容，此处不再赘述。
在一些实施例中，为实现显示面板的彩色显示，显示面板包括：发出蓝色光的第一量子点发光二极管和发出其他颜色光的第二量子点发光二极管，至少第一量子点发光二极管为所述量子点发光二极管；第一量子点发光二极管中微腔结构的数量多于所述第二量子点发光二极管中微腔结构的数量。
其中，上述其他颜色光具体可以为红色光、绿色光、青色光、品红色光和黄色光中至少之一。作为一个示例，显示面板上包括发出蓝色光的蓝光量子点发光二极管(第一量子点发光二极管)、发出红色光的红光量子点发光二极管(一种第二量子点发光二极管)、发出绿色光的绿光量子点发光二极管(一种第二量子点发光二极管)。
其中，可以仅在蓝光量子点发光二极管中设置光调控层，而在红光量子点发光二极管和绿光量子点发光二极管中不设置层，以使得蓝光量子点发光二极管中微腔结构数量多于红光量子点发光二极管和绿光量子点发光二极管中的微腔结构数量；或者，蓝光量子点发光二极管、红光量子点发光二极管和绿光量子点发光二极管中均设置有光调控层，但是蓝光量子点发光二极管中光调控层的数量多于红光量子点发光二极管和绿光量子点发光二极管中光调控层的数量。
在本公开实施例中，优选是在蓝光量子点发光二极管中设置光调控层，这是因为通过实验模拟出在蓝光量子点发光二极管中设置上述光调控层后，蓝光量子点发光二极管的光取出率能够有明显提升，光量子点 发光二极管的光取出率可以达到≥25％的水平。
在红光量子点发光二极管和绿光量子点发光二极管中设置光调控层时，通过实现模拟结果发现，红光量子点发光二极管和绿光量子点发光二极管的光取出率相较于未设置光调控层时所有提升，但是光取出率的提升效果没有蓝光量子点发光二极管的提升效果明显。
本公开实施例所提供的显示面板可应用至显示装置中，显示装置可以为电视、数码相机、手机、平板电脑等任何具有显示功能的产品或者部件。
可以理解的是，以上实施方式仅仅是为了说明本公开的原理而采用的示例性实施方式，然而本公开并不局限于此。对于本领域内的普通技术人员而言，在不脱离本公开的精神和实质的情况下，可以做出各种变型和改进，这些变型和改进也视为本公开的保护范围。

Claims (18)

  1. 一种量子点发光二极管，其中，包括：第一电极、第二电极、设置在所述第一电极与所述第二电极之间的量子点发光层，所述第一电极和所述第二电极中之一为反射电极，另一为透射电极或半透半反电极；
    在所述第一电极与所述第二电极之间设置有至少一层光调控层，所述光调控层配置为与所述反射电极构成微腔结构，使所述量子点发光二极管的光取出效率P满足：25％≤P≤98％。
  2. 根据权利要求1所述的量子点发光二极管，其中，所述光调控层的透过率Q满足：70％≤Q＜100％；
    所述光调控层的反射率R满足：0＜R≤30％。
  3. 根据权利要求1所述的量子点发光二极管，其中，所述光调控层的厚度包括：1nm～35nm。
  4. 根据权利要求1所述的量子点发光二极管，其中，所述光调控层的折射率包括：0.1～0.3。
  5. 根据权利要求1所述的量子点发光二极管，其中，所述光调控层的材料包括半导体材料或金属材料。
  6. 根据权利要求5所述的量子点发光二极管，其中，所述光调控层的材料包括所述金属材料，所述光调控层与所述量子点发光层不直接接触。
  7. 根据权利要求1所述的量子点发光二极管，其中,所述光调控层与所述反射电极之间存在至少一层功能介质层且满足：
    Figure PCTCN2022088688-appb-100001
    φ 1表示光线在所述反射电极上发生反射所产生的相移，φ 2表示光线在所述光调控层上发生反射所产生的相移，k表示位于所述光调控层与所述反射电极之间的所述功能介质层的数量，n i和d i分别表示靠近所述反射电极的第i层所述功能介质层的折射率和厚度，m 1为预先配置的正整数，λ表示量子点发光层的发光峰值波长，i为整数且1≤i≤k。
  8. 根据权利要求5所述的量子点发光二极管，其中，所述第一电极和所述第二电极中之一为反射电极，另一为半透半反电极；
    位于所述半透半反电极与所述反射电极之间的功能介质层满足：
    Figure PCTCN2022088688-appb-100002
    φ 3表示光线在所述半透半反电极上发生反射所产生的相移，s表示位于所述半透半反电极与所述反射电极之间的所述功能介质层的数量，n j和d j分别表示靠近所述反射电极的第j层所述功能介质层的折射率和厚度，m 2为预先配置的正整数且m 2＞m 1，j为整数且1≤j≤s。
  9. 根据权利要求1所述的量子点发光二极管，其中，所述第一电极与所述第二电极中之一作为所述量子点发光二极管的阴极，另一作为所述量子点发光二极管的阳极；
    所述阴极与所述量子点发光层之间设置有电子传输层；
    所述阳极与所述量子点发光层之间设置有空穴注入层和空穴传输层。
  10. 根据权利要求9所述的量子点发光二极管，其中，所述至少一层光调控层包括：第一光调控层，所述第一光调控层的材料包括半导体材料；
    所述第一光调控层位于所述阳极与所述量子点发光层之间，所述第一光调控层的HOMO能级与所述空穴传输层的HOMO能级的差的绝对值大于1eV。
  11. 根据权利要求9所述的量子点发光二极管，其中，所述至少一层光调控层包括：第二光调控层，所述第二光调控层的材料包括半导体材料；
    所述第二光调控层位于所述阴极与所述量子点发光层之间，所述第二光调控层的HOMO能级与所述空穴传输层的HOMO能级的差的绝对值小于0.5eV，所述第二光调控层的LUMO能级与所述空穴传输层的LUMO能级的差的绝对值大于1eV。
  12. 根据权利要求1所述的量子点发光二极管，其中，所述光调控层远离所述量子点发光层的一侧表面上的至少部分区域呈外凸形貌或内凹形貌；
    和/或，所述光调控层靠近所述量子点发光层的一侧表面上的至少部分区域呈外凸形貌或内凹形貌。
  13. 根据权利要求1至12中任一所述的量子点发光二极管，其中，还包括：衬底基板，所述第一电极位于所述衬底基板上，所述第二电极位于所述第一电极远离所述衬底基板的一侧；
    所述第一电极为反射电极，所述第二电极为半透半反电极，所述反 射电极与所述半透半反电极构成微腔结构；
    或者，所述第一电极为透射电极，所述第二电极为反射电极。
  14. 根据权利要求13所述的量子点发光二极管，其中，所述反射电极作为所述量子点发光二极管的阳极，所述反射电极的材料包括金属材料；
    在所述反射电极靠近所述量子点发光层的一侧设置有与所述反射电极相邻的金属氧化物电极。
  15. 一种显示面板，其中，包括：如上述权利要求1至14中任一所述量子点发光二极管。
  16. 根据权利要求15所述的显示面板，其特征在于，所述显示面板包括：发出蓝色光的第一量子点发光二极管和发出其他颜色光的第二量子点发光二极管，至少所述第一量子点发光二极管为所述量子点发光二极管；
    所述第一量子点发光二极管中微腔结构的数量多于所述第二量子点发光二极管中微腔结构的数量。
  17. 一种如权利要求1至14中任一所述量子点发光二极管的制备方法，其中，包括：
    形成第一电极、第二电极、量子点发光层和至少一层光调控层，所述量子点发光层位于所述第一电极与所述第二电极之间，所述第一电极和所述第二电极中之一为反射电极，另一为透射电极或半透半反电极；所述光调控层配置为与所述反射电极构成微腔结构，使所述量子点发光二极管的光取出效率P满足：25％≤P≤98％
  18. 根据权利要求17所述的制备方法，其特征在于，所述光调控层通过蒸镀工艺、旋涂工艺或打印工艺进行制备。
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Citations (4)

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US20070075634A1 (en) * 2005-09-30 2007-04-05 Au Optronics Corp. Trans-reflective organic electroluminescent panel and method of fabricating the same
US20080272991A1 (en) * 2007-05-02 2008-11-06 Au Optronics Corp. Organic Electroluminescence Pixel, Organic Electroluminescence Device, and Manufacturing Method Thereof
US20090230845A1 (en) * 2005-03-17 2009-09-17 Idemitsu Kosan Co., Ltd Organic electroluminescent device
CN104335380A (zh) * 2012-07-30 2015-02-04 索尼公司 发光器件、包括该发光器件的显示部以及电子设备

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Publication number Priority date Publication date Assignee Title
US20090230845A1 (en) * 2005-03-17 2009-09-17 Idemitsu Kosan Co., Ltd Organic electroluminescent device
US20070075634A1 (en) * 2005-09-30 2007-04-05 Au Optronics Corp. Trans-reflective organic electroluminescent panel and method of fabricating the same
US20080272991A1 (en) * 2007-05-02 2008-11-06 Au Optronics Corp. Organic Electroluminescence Pixel, Organic Electroluminescence Device, and Manufacturing Method Thereof
CN104335380A (zh) * 2012-07-30 2015-02-04 索尼公司 发光器件、包括该发光器件的显示部以及电子设备

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