Heterojunction nanomaterials, electron transport thin films, and display devices

Abstract

The application relates to a kind of heterojunction nanomaterials, electron transport film and display device.The heterojunction nanomaterials include: first metal selenide and second metal selenide compounded on the first metal selenide, second metal selenide is silver doped metal selenide, and heterojunction is formed between the first metal selenide and second metal selenide.The heterojunction nanomaterials contain first metal selenide and second metal selenide compounded on the first metal selenide, second metal selenide is silver doped metal selenide, and heterojunction is formed between the first metal selenide and second metal selenide, thereby facilitating free electron migration, so that the heterojunction nanomaterials have higher conductivity;In addition, the heterojunction nanomaterials have better light scattering effect than pure metal selenide nanomaterials.

Description

Technical Field

[0001] This invention relates to the field of display technology, and in particular to a heterojunction nanomaterial, an electron transport thin film, and a display device. Background Technology

[0002] With the rapid development of display technology, display devices such as quantum dot light-emitting diodes (QLEDs) have received widespread attention. Among them, quantum dot light-emitting diodes (QLEDs), which use semiconductor quantum dot materials as the light-emitting layer, have broad application prospects in flat panel displays, solid-state lighting, and other fields due to their excellent characteristics such as high color purity, high luminous efficiency, adjustable emission color, and device stability.

[0003] For quantum dot light-emitting diodes, zinc oxide is a common electron transport layer material. However, zinc oxide has many defect states, which can easily cause leakage current when used as an electron transport layer. In addition, zinc oxide has poor stability in the environment, which makes the display device have significant stability problems. Summary of the Invention

[0004] Based on this, the present invention provides a heterojunction nanomaterial, an electron transport thin film, and a display device. The heterojunction nanomaterial has high electrical conductivity and good light scattering effect. When used as an electron transport layer in a display device, it can effectively improve the light emission performance and stability of the display device.

[0005] The technical solution of the present invention to solve the above-mentioned technical problems is as follows.

[0006] A heterojunction nanomaterial, comprising:

[0007] A first metal selenide and a second metal selenide composited on the first metal selenide, wherein the second metal selenide is a silver-doped metal selenide, and a heterojunction is formed between the first metal selenide and the second metal selenide.

[0008] In some embodiments, in the heterojunction nanomaterial, the first metal selenide is a nanorod, and the second metal selenide is nanoparticles distributed on the surface of the first metal selenide.

[0009] In some embodiments, in the heterojunction nanomaterial, the diameter of the first metal selenide is 20 nm to 30 nm, and the length is 30 nm to 100 nm.

[0010] In some embodiments, the particle size of the second metal selenide in the heterojunction nanomaterial is 10 nm to 20 nm.

[0011] In some embodiments, in the heterojunction nanomaterial, the first metal selenide is selected from at least one of SnSe, Sb2Se3, In4Se3, ZnSe, MoSe2 and WSe2.

[0012] In some embodiments, in the heterojunction nanomaterial, the second metal selenide is selected from at least one of AgSnSe, AgSbSe2, AgIn3Se3, AgZnSe, AgMoSe2, and AgWSe2.

[0013] In some embodiments, the mass ratio of the second metal selenide to the first metal selenide in the heterojunction nanomaterial is (0.2-0.5):1.

[0014] The present invention provides an electron transport thin film, wherein the composition of the electron transport thin film comprises the above-mentioned heterojunction nanomaterial.

[0015] This invention provides a display device, comprising:

[0016] The anode, quantum dot light-emitting layer, electron transport layer, and cathode are stacked in sequence.

[0017] The electron transport layer comprises the heterojunction nanomaterials described above, or the electron transport layer is the electron transport thin film described above.

[0018] In some embodiments, the display device further includes:

[0019] A hole transport layer is disposed between the anode and the light-emitting layer; the hole transport layer comprises a third metal selenide, which is a p-type doped metal selenide.

[0020] In some embodiments, the p-type doping element in the display device is selected from at least one of Sn, Zn, and Mo.

[0021] In some embodiments, in the display device, the metal selenide in the third metal selenide is selected from at least one of SnSe, Sb2Se3, In4Se3, ZnSe, MoSe2 and WSe2, wherein the p-type dopant element is different from the element contained in the metal selenide in the third metal selenide.

[0022] In some embodiments, the general formula of the p-type doped metal selenide in the display device is (Sn x Sb 1-x )2Se3; where 0 < x < 0.9.

[0023] In some embodiments, the anode material in the display device is at least one of indium tin oxide, indium zinc oxide, and aluminum-doped zinc oxide.

[0024] In some embodiments, the material of the quantum dot light-emitting layer in the display device is selected from at least one of CdS, ZnSe, and CdZnS.

[0025] In some embodiments, the cathode material in the display device is selected from at least one of Ag, Au, Al, and Cu.

[0026] Compared with the prior art, the heterojunction nanomaterials and display devices of the present invention have the following beneficial effects:

[0027] The aforementioned heterojunction nanomaterial contains a first metal selenide and a second metal selenide composited on the first metal selenide. The second metal selenide is a silver-doped metal selenide. A heterojunction is formed between the first metal selenide and the second metal selenide, which is conducive to the migration of free electrons, resulting in the heterojunction nanomaterial having a high electrical conductivity. In addition, the heterojunction nanomaterial has better light scattering effect than simple metal selenide nanomaterials.

[0028] The aforementioned display device contains the aforementioned heterojunction nanomaterial in its electron transport layer, which can effectively reduce the potential barrier of charge carriers during interface transport, increase the carrier mobility, and improve the light extraction performance of the device by utilizing the heterojunction effect and better light scattering effect, thereby improving the external quantum efficiency and other light extraction performance; at the same time, it can also improve the stability of the display device and extend the service life of the display device. Attached Figure Description

[0029] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0030] Figure 1 This is a schematic diagram of the structure of a display device provided in one embodiment.

[0031] Explanation of reference numerals in the attached figures:

[0032] 11: Anode; 12: Quantum dot light-emitting layer; 13: Electron transport layer; 14: Cathode; 15: Substrate; 16: Hole transport layer. Detailed Implementation

[0033] The heterojunction nanomaterials, electron transport thin films, and display devices of the present invention are further described in detail below with reference to specific embodiments. The present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the present invention.

[0034] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the specification of this invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0035] In the description of this invention, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0036] The weights of the relevant components mentioned in the embodiments of this invention can refer not only to the specific content of each component, but also to the proportional relationship between the weights of the components. Therefore, any scaling up or down of the content of the relevant components according to the embodiments of this invention is within the scope disclosed in the embodiments of this invention. Specifically, the weights mentioned in the embodiments of this invention can be well-known units of mass in the chemical industry, such as μg, mg, g, and kg.

[0037] One embodiment of the present invention provides a heterojunction nanomaterial, comprising: a first metal selenide and a second metal selenide composited on the first metal selenide, wherein the second metal selenide is a silver-doped metal selenide, and a heterojunction is formed between the first metal selenide and the second metal selenide.

[0038] It is understandable that silver is a doped metal in the second metal selenide; in other words, the metal element in the metal selenide of the second metal selenide is not silver.

[0039] The aforementioned heterojunction nanomaterial contains a first metal selenide and a second metal selenide composited on the first metal selenide. The second metal selenide is a silver-doped metal selenide. A heterojunction is formed between the first metal selenide and the second metal selenide, which is conducive to the migration of free electrons, resulting in the heterojunction nanomaterial having a high electrical conductivity. In addition, the heterojunction nanomaterial has better light scattering effect than simple metal selenide nanomaterials.

[0040] In some examples, in the heterojunction nanomaterial, the first metal selenide is a nanorod, and the second metal selenide is nanoparticles distributed on the surface of the first metal selenide. This further facilitates the migration of free electrons from the second metal selenide to the surface of the first metal selenide, thereby further enhancing the electrical conductivity of the heterojunction nanomaterial. It should be noted that when the second metal selenide is nanoparticles distributed on the surface of the nanorod-shaped first metal selenide, the specific distribution of the second metal selenide is not particularly limited, as long as it is distributed on the surface of the first metal selenide; for example, it can be spaced apart on the surface of the first metal selenide.

[0041] In some examples, in the heterojunction nanomaterial, the diameter of the first metal selenide is 20 nm to 30 nm and the length is 1000 nm to 2000 nm; alternatively, the diameter of the first metal selenide is 20 nm to 25 nm and the length is 1000 nm to 1500 nm; alternatively, the diameter of the first metal selenide is 20 nm and the length is 1000 nm.

[0042] In some of these examples, the particle size of the second metal selenide in the heterojunction nanomaterial is 10 nm to 20 nm; alternatively, the particle size of the second metal selenide is 10 nm to 15 nm; alternatively, the particle size of the second metal selenide is 10 nm.

[0043] In some of these examples, the first metal selenide in the heterojunction nanomaterial is selected from at least one of SnSe, Sb2Se3, In4Se3, ZnSe, MoSe2, and WSe2.

[0044] In some specific examples, in heterojunction nanomaterials, the first metal selenide is selected from at least one of Sb₂Se₃ and ZnSe.

[0045] In some of these examples, the second metal selenide in the heterojunction nanomaterial is selected from at least one of AgSnSe, AgSbSe3, AgIn3Se3, AgZnSe, AgMoSe2, and AgWSe2.

[0046] It is understood that the type of metal selenide in the second metal selenide can be the same as or different from that in the first metal selenide; optionally, the type of metal selenide in the second metal selenide can be the same as that in the first metal selenide. For example, when the first metal selenide is SnSe, the second metal selenide is AgSnSe; when the first metal selenide is Sb2Se3, the second metal selenide is AgSbSe3; when the first metal selenide is In4Se3, the second metal selenide is AgIn3Se3; when the first metal selenide is ZnSe, the second metal selenide is AgZnSe; when the first metal selenide is MoSe2, the second metal selenide is AgMoSe2; when the first metal selenide is WSe2, the second metal selenide is AgWSe2.

[0047] In some specific examples, the first metal selenide in the heterojunction nanomaterial is Sb₂Se₃, and the second metal selenide is AgSbSe₃. This can further improve the performance of the heterojunction nanomaterial.

[0048] In some examples, the mass ratio of the second metal selenide to the first metal selenide in the heterojunction nanomaterial is (0.2–0.5):1; alternatively, the mass ratio is (0.25–0.43):1. By controlling the mass ratio of the second metal selenide to the first metal selenide, it is beneficial to control the electrical conductivity of the material and the transport of charge carriers.

[0049] One embodiment of the present invention provides the above-mentioned heterojunction nanomaterial as an electron transport layer material, or its application in the preparation of an electron transport layer.

[0050] One embodiment of the present invention provides an electron transport thin film, wherein the composition of the electron transport thin film includes the above-mentioned heterojunction nanomaterial.

[0051] In some of these examples, the electron transport thin film is made of the aforementioned heterojunction nanomaterial.

[0052] Please see Figure 1 One embodiment of the present invention provides a display device 10, comprising: an anode 11, a quantum dot light-emitting layer 12, an electron transport layer 13 and a cathode 14 stacked sequentially, wherein the electron transport layer 14 comprises the heterojunction nanomaterial described above, or the electron transport thin film described above.

[0053] The aforementioned display device 10 contains a heterojunction nanomaterial with a specific composition in its electron transport layer 14. This heterojunction nanomaterial contains a first metal selenide and a second metal selenide that have heterojunction effects, which facilitates the migration of free electrons from the second metal selenide to the surface of the first metal selenide, resulting in high electrical conductivity of the heterojunction nanomaterial. Therefore, this display device can effectively reduce the potential barrier for charge carriers during interface transport, increase charge carrier mobility, and improve the light extraction performance of the device by utilizing the heterojunction effect and good light scattering effect, thereby improving the external quantum efficiency and other light extraction performance. At the same time, it can also improve the thermal stability of the display device, thereby extending the service life of the display device.

[0054] In some examples, the electron transport layer 13 in the display device 10 has a thickness of 20 nm to 100 nm; optionally, the electron transport layer 13 has a thickness of 30 nm to 100 nm; optionally, the electron transport layer 13 has a thickness of 50 nm.

[0055] Understandably, in some examples, the display device 10 also includes a substrate 15. Further, an anode 11, a light-emitting layer 12, an electron transport layer 13, and a cathode 14 are sequentially stacked on the substrate 15.

[0056] Furthermore, the substrate 15 may be a rigid material (e.g., glass) or a flexible material (e.g., polyimide).

[0057] In some examples, the display device 10 also includes a hole transport layer 16 disposed between the anode 11 and the light-emitting layer 13. The hole transport layer 16 contains a third metal selenide, which is a P-type doped metal selenide.

[0058] In some of these examples, the p-type dopant element in the display device 10 is selected from at least one of Sn, Zn, and Mo.

[0059] In some of these examples, in the display device 10, the metal selenide in the third metal selenide is selected from at least one of SnSe, Sb2Se3, In4Se3, ZnSe, MoSe2 and WSe2, wherein the p-type dopant element is different from the element contained in the metal selenide in the third metal selenide.

[0060] It is understandable that when the metal selenide in the third metal selenide is SnSe, the p-type dopant element can be selected from Zn or Mo; in this case, the general formula of the third metal selenide is Zn. x Sn 1-x Se or Mo x Sn 1-xSe; When the metal selenide in the third metal selenide is Sb₂Se₃, the p-type dopant element can be selected from Sn, Zn, or Mo. In this case, the third metal selenide is (Sn x Sb 1-x )2Se3、(Zn x Sb 1-x )2Se3 or (Mo x Sb 1-x When the metal selenide in the third metal selenide is In4Se3, the p-type dopant element can be selected from Sn, Zn, or Mo. In this case, the third metal selenide is (Sn2Se3); x In 1-x )4Se3、(Zn x In 1-x )4Se3 or (Mo x In 1-x )4Se3; When the metal selenide in the third metal selenide is ZnSe, the p-type dopant element is selected from Sn or Mo, and the third metal selenide is Sn x Zn 1-x Se or Mo x Zn 1-x Se; When the metal selenide in the third metal selenide is MoSe2, the p-type dopant can be selected from Sn or Zn, in which case the third metal selenide is Sn. x Mo 1-x Se2 or Zn x Mo 1-x Se2; When the metal selenide in the third metal selenide is WSe2, the p-type dopant can be selected from Sn, Zn, or Mo, in which case the third metal selenide is Sn. x W 1-x Se2, Zn x W 1-x Se2 or Mo x W 1-x Se2; where x > 0, 1-x > 0. Traditional hole transport layer materials are typically TFB (poly[(9,9-di-n-octylfluorenyl-2,7-diyl)-alt-(4,4'-(N-(4-n-butyl)phenyl)-diphenylamine)]), but TFB, as a hole transport layer, has a high potential barrier when injected into the quantum dot light-emitting (QD) layer, making injection difficult. This leads to holes easily clogging the interface between the hole transport layer and the light-emitting layer, causing the TFB layer to degrade and affecting device stability. Doping metal selenides with specific types of p-type elements effectively improves the conductivity of p-type selenides. Using this p-type selenide as the hole transport layer in a quantum dot LED effectively reduces the potential barrier for carrier transport at the interface, thereby promoting hole transport and enabling faster recombination of holes and electrons.

[0061] In some of the preferred examples, in display device 10, the metal selenide in the third metal selenide is Sb2Se3.

[0062] The defect binding energy of Sb2Se3 is relatively small, and the defects have a low ability to trap charge carriers, which reduces the nonradiative recombination of holes and electrons in the transport layer.

[0063] It can also be understood that when the metal selenide in the third metal selenide is Sb2Se3, the P-type dopant element is selected from at least one of Sn, Zn and Mo.

[0064] Sn, Zn, and Mo have a lower valence electron ratio than Sb, which is beneficial for the formation of hole conductivity in the materials.

[0065] It is understandable that the general formula for the third metal selenide (P-type doped metal selenide) is (Sn x Sb 1-x )2Se3、(Zn x Sb 1-x )2Se3 or (Mo x Sb 1-x )2Se3; where 0 < x < 0.9. Further, x can be 0.1, 0.3, 0.5, 0.7, 0.9, etc. Optionally, 0.1 < x < 0.5; alternatively, x = 0.5.

[0066] The carrier mobility of the hole transport layer can be adjusted by using different doping ratios.

[0067] Furthermore, in some examples, when the metal selenide in the third metal selenide of the display device 10 is Sb₂Se₃, the P-type dopant can be Sn. Using Sn doping, Sn replaces Sb to form a P-type semiconductor, and Sn doping can also form a smaller interface barrier with the ITO electrode, resulting in higher stability of the hole transport layer. In other words, the general formula for the third metal selenide (P-type doped metal selenide) is (Sn₂Se₃)₂Se₃. x Sb 1-x )2Se3(0<x<0.9).

[0068] In some examples, the hole transport layer 16 in the display device 10 has a thickness of 20 nm to 100 nm; optionally, the hole transport layer 16 has a thickness of 20 nm to 50 nm; optionally, the hole transport layer 16 has a thickness of 25 nm.

[0069] It is understood that the anode 11, the light-emitting layer 12 and the cathode 14 can be made of materials commonly used in the art, and the present invention does not limit them.

[0070] In some of these examples, the anode material in display device 10 is selected from at least one of indium tin oxide, indium zinc oxide, and aluminum-doped zinc oxide; alternatively, the anode material is indium tin oxide.

[0071] In some of these examples, the anode in display device 10 also includes a metallic reflective layer.

[0072] In some specific examples, the anode 11 in the display device 10 has an Ag / ITO or ITO / Ag / ITO structure.

[0073] In some examples, the light-emitting layer in display device 10 is a quantum dot light-emitting layer 12, in which case display device 10 is a quantum dot light-emitting diode. It is understood that the light-emitting layer in display device 10 can be a blue, red, or green light-emitting layer. It is also understood that the type of light-emitting layer is not limited to these; in some examples, the light-emitting layer can also be an organic light-emitting layer.

[0074] In some of these examples, the quantum dot light-emitting layer 12 in the display device 10 is made of core-shell quantum dots or gradient-shell-based quantum dot materials.

[0075] In some examples, the quantum dot light-emitting layer 12 in the display device 10 is made of at least one of CdS, ZnSe and CdZnS; alternatively, the quantum dot light-emitting layer 12 is made of CdS / ZnSe or CdZnS / ZnSe.

[0076] In some of these examples, the cathode material in display device 10 is selected from at least one of Ag, Au, Al, and Cu.

[0077] In some of these examples, the thickness of the light-emitting layer in the display device 10 is 20 nm to 30 nm.

[0078] An embodiment of the present invention provides a method for preparing the above-described display device 10, including steps S100 to S600.

[0079] Step S100: Form an anode 11 on the substrate 16. Step S200: Form a hole transport layer 16 on the anode 11.

[0080] In some of these examples, in step S200, the material of the hole transport layer 16 described above is used to prepare a target for magnetron sputtering, and the hole transport layer 16 is formed on the anode 11 by magnetron sputtering.

[0081] In some of these examples, the magnetron sputtering conditions in step S200 are: power 60W to 80W, speed 1nm / min to 5nm / min, pressure 0.6Pa to 1.2Pa, and time 10min to 30min.

[0082] In some of these examples, in step S200, magnetron sputtering is performed under argon conditions at a flow rate of 5 sccm to 20 sccm.

[0083] In some specific examples, in step S200, the magnetron sputtering conditions are: power 12W, rate 2nm / min, pressure 1Pa, argon flow rate 10sccm, and sputtering time 15min.

[0084] Step S300: Form a light-emitting layer on the hole transport layer 16.

[0085] Step S400: An electron transport layer 13 is formed on the light-emitting layer, wherein the preparation of the electron transport layer 13 includes steps S410 to S450.

[0086] Step S410: Mix the selenium source and the first organic solvent, and keep it at 100℃~500℃ for 2h~8h to obtain the first precursor solution.

[0087] In some of these examples, in step S410, the selenium source is selected from at least one of selenium dioxide, amine selenide, and hydrogen selenide; alternatively, the selenium source is selenium oxide.

[0088] In some examples, in step S410, the first organic solvent is selected from at least one of octadecene (ODE), oleic acid, and oleylamine; optionally, the first organic solvent is selected from at least one of octadecene and oleic acid; optionally, the first organic solvent is octadecene.

[0089] In some of these examples, in step S410, the temperature is maintained at 100℃ to 300℃ for 3 to 6 hours.

[0090] In some specific examples, in step S410, the temperature is maintained at 200°C for 5 hours.

[0091] Step S420: Mix the metal salt, surfactant, and second organic solvent, and keep warm at 100℃~500℃ for 0.1h~1h to obtain the second precursor solution.

[0092] In some of these examples, in step S420, the temperature is maintained in a nitrogen atmosphere.

[0093] In some of these examples, in step S420, the metal salt is selected from at least one of tin acetate, antimony acetate, indium acetate, zinc acetate, molybdenum acetate, and tungsten acetate.

[0094] In some of these examples, in step S420, the surfactant is selected from at least one of hexadecylacrylamide (HDA) and oleic acid (OA); alternatively, the surfactant is selected from both hexadecylacrylamide (HDA) and oleic acid (OA).

[0095] In some of these examples, in step S420, the second organic solvent is selected from at least one of octadecene (ODE), oleic acid, and oleylamine; alternatively, the second organic solvent is selected from at least one of octadecene and oleic acid; alternatively, the second organic solvent is octadecene.

[0096] It is understood that the first organic solvent and the second organic solvent can be the same or different. Optionally, the first organic solvent and the second organic solvent can be the same.

[0097] In some of these examples, in step S420, the temperature is maintained at 100℃ to 300℃ for 0.5h to 1h.

[0098] In some specific examples, in step S420, the temperature is maintained at 220°C for 1 hour.

[0099] Step S430: Take a certain volume of the first precursor solution and the second precursor solution, mix them, and react at 200℃~300℃. It can be understood that the volume of the first precursor solution is based on the mass ratio of the second metal selenide to the first metal selenide.

[0100] Step S440: Add silver salt and the remaining first precursor solution to the reaction solution from step S430 and continue the reaction.

[0101] It is understandable that step S430 generates a first metal selenide nanorod, and step S440 generates a second metal selenide particle on the surface of the first metal selenide nanorod.

[0102] Step S500: Form a cathode 14 on the electron transport layer 13.

[0103] Step S600: An encapsulation layer (not shown) is formed on the cathode 14 to encapsulate the light-emitting layer.

[0104] The aforementioned display device uses selenide semiconductor materials as the transport layer material. Specifically, it uses a heterojunction nanomaterial of a first metal selenide and a second metal selenide (silver-doped metal selenide) as the electron transport layer and a specific third metal selenide (P-type-doped metal selenide) as the hole transport layer. This effectively reduces the carrier transport interface barrier and increases carrier mobility. The interfaces of each functional layer have good thermal matching, which effectively improves the thermal stability of the display device and extends its lifespan. Specific Implementation

[0106] The following examples of heterojunction nanomaterials, electron transport films, and display devices according to the present invention are for illustrative purposes only. It should be understood that the heterojunction nanomaterials, electron transport films, and display devices of the present invention are not limited to the following embodiments.

[0107] Example 1

[0108] The specific structure of a quantum dot light-emitting diode is: substrate / anode [(Ag, 150nm) / ITO, 15nm)] / hole transport layer (Sn) 0.1 Sb 0.9 )2Se3, 25nm) / Light-emitting layer (CdS / ZnSe, 20nm) / Electron transport layer (AgSbSe2 / Sb2Se3, 30nm) / Cathode (silver, 20nm) / Encapsulation layer.

[0109] (1) Provide an Ag(150nm) / ITO(15nm) electrode, which is the anode, formed on the substrate;

[0110] (2) Preparation of hole transport layer

[0111] 60g (Sn) 0.1 Sb 0.9 2Se3 (containing 3g Sn, 27.4g Sb, and 29.6g Se) was prepared as a target for magnetron sputtering. A hole transport layer was formed on an Ag (150nm) / ITO (15nm) electrode using magnetron sputtering. The RF sputtering power was 72W, the sputtering rate was 2nm / min, the sputtering pressure was 1Pa, the Ar gas flow rate was 10sccm, the sputtering time was 15min, and the film thickness was 25nm.

[0112] (3) Fabrication of quantum dot light-emitting layer

[0113] CdS / ZnSe nanoparticles with a particle size of approximately 12 nm were dissolved in chloroform solvent at a concentration of 10 mg / ml, and 9 drops were printed on the hole transport layer and dried; the film thickness was approximately 20 nm.

[0114] (4) Preparation of electron transport layer (AgSbSe2 / Sb2Se3 material):

[0115] Add 24 mmol SeO2 and 30 mL of organic solvent octadecene (ODE), stir and heat to 200 °C, keep warm for 5 h, SeO2 completely dissolves, and 0.8 mol / L Se-ODE precursor solution is obtained;

[0116] 1.2 mmol Sb(CH3COO)3, 8 mmol hexadecylacrylamide (HDA), 15 mL ODE and 6 mL oleic acid (OA) were added to a flask, stirred and heated to 220 °C under a nitrogen atmosphere, and kept at this temperature for 1 h to obtain the antimony precursor solution.

[0117] 2 mL of Se-ODE precursor solution was added to antimony precursor solution and reacted at 240 °C for 2 min. Then, 0.4 mmol of CH3COOAg was added and stirred for 3 min. Next, 6 mL of Se-ODE precursor solution was added and reacted for 10 min to obtain AgSbSe2 / Sb2Se3 heterojunction nanorods with a mass ratio of AgSbSe2 to Sb2Se3 of 0.25:1. The Sb2Se3 particles had a diameter of 20 nm and a length of 1000 nm, while the AgSbSe2 particles had a diameter of 10 nm.

[0118] AgSbSe2 / Sb2Se3 heterojunction nanorods were prepared into 20 mg / mL ink, and 10 drops were printed on the quantum dot luminescent layer film. After drying, the thickness was about 30 nm, which is the electron transport layer film.

[0119] (5) Stacked cathodes.

[0120] (6) Packaging.

[0121] Example 2

[0122] The specific structure of a quantum dot light-emitting diode is: substrate / anode [(Ag, 150nm) / ITO, 15nm)] / hole transport layer (Sn) 0.5 Sb 0.5 )2Se3, 25nm) / Light-emitting layer (CdS / ZnSe, 20nm) / Electron transport layer (AgSbSe2 / Sb2Se3, 30nm) / Cathode (silver, 20nm) / Encapsulation layer.

[0123] The process is basically the same as in Example 1, except that the hole transport layer is prepared differently in step (2); that is, the hole transport layer is different. Step (2) is as follows:

[0124] (2) Preparation of hole transport layer

[0125] 60g (Sn) 0.5 Sb 0.5 2Se3 (containing 14.9 g Sn, 15.3 g Sb, and 29.8 g Se) was prepared as a target for magnetron sputtering. A hole transport layer was formed on an Ag (150 nm) / ITO (15 nm) substrate electrode using magnetron sputtering. The RF sputtering power was 70 W, the sputtering rate was 2 nm / min, the sputtering pressure was 1 Pa, the Ar gas flow was 10 sccm, the sputtering time was 15 min, and the film thickness was 25 nm.

[0126] Example 3

[0127] The specific structure of a quantum dot light-emitting diode is: substrate / anode [(Ag, 150nm) / ITO, 15nm)] / hole transport layer (Sn) 0.3 Sb 0.7)2Se3, 25nm) / Light-emitting layer (CdS / ZnSe, 20nm) / Electron transport layer (AgSbSe2 / Sb2Se3, 30nm) / Cathode (silver, 20nm) / Encapsulation layer.

[0128] The process is basically the same as in Example 1, except that the hole transport layer is prepared differently in step (2); that is, the hole transport layer is different. Step (2) is as follows:

[0129] (2) Preparation of hole transport layer

[0130] 60g (Sn) 0.3 Sb 0.7 2Se3 (containing 8.9 g Sn, 21.4 g Sb, and 29.7 g Se) was prepared as a target for magnetron sputtering. A hole transport layer was formed on an Ag (150 nm) / ITO (15 nm) substrate electrode using magnetron sputtering. The RF sputtering power was 70 W, the sputtering rate was 2 nm / min, the sputtering pressure was 1 Pa, the Ar gas flow was 10 sccm, the sputtering time was 15 min, and the film thickness was 25 nm.

[0131] Example 4

[0132] The specific structure of a quantum dot light-emitting diode is: substrate / anode [(Ag, 150nm) / ITO, 15nm)] / hole transport layer (Sn) 0.1 Sb 0.9 )2Se3, 25nm) / Light-emitting layer (CdS / ZnSe, 20nm) / Electron transport layer (ZnSe / AgZnSe, 30nm) / Cathode (silver, 20nm) / Encapsulation layer.

[0133] The process is basically the same as in Example 1, except that the electron transport layer material prepared in step (4) is different; that is, the electron transport layer is different. Step (4) is as follows:

[0134] (4) Preparation of electron transport layer (ZnSe / AgZnSe material): Add 24 mmol SeO2 and 30 mL organic solvent octadecene (ODE), stir and heat to 200℃, keep warm for 5 h, SeO2 completely dissolves, and 0.8 mol / L Se-ODE precursor solution is obtained;

[0135] 2 mmol Zn(CH3COO), 8 mmol hexadecylacrylamide (HDA), 15 mL ODE and 6 mL oleic acid (OA) were added to a flask, stirred and heated to 220 °C under a nitrogen atmosphere, and kept at this temperature for 1 h to obtain a zinc precursor solution.

[0136] 2 mL of Se-ODE precursor solution was added to zinc precursor solution and reacted at 240 °C for 2 min. Then 0.4 mmol of CH3COOAg was added and stirred for 3 min. Then 6 mL of Se-ODE precursor solution was added and reacted for 10 min to obtain ZnSe / AgZnSe heterojunction nanorods with a ZnSe / AgZnSe mass ratio of 0.43:1.

[0137] ZnSe / AgZnSe heterojunction nanorods were prepared into 20 mg / mL ink, and 10 drops were printed on the quantum dot luminescent layer film. After drying, the thickness was about 30 nm, which is the electron transport layer film.

[0138] Example 5

[0139] The specific structure of a quantum dot light-emitting diode is: substrate / anode [(Ag, 150nm) / ITO, 15nm)] / hole transport layer (Sn) 0.1 Sb 0.9 )2Se3, 25nm) / Light-emitting layer (CdS / ZnSe, 20nm) / Electron transport layer (AgSbSe2 / Sb2Se3, 30nm) / Cathode (silver, 20nm) / Encapsulation layer.

[0140] (1) Provide an Ag(150nm) / ITO(15nm) electrode, which is the anode, formed on the substrate;

[0141] (2) Preparation of hole transport layer

[0142] 60g (Sn) 0.1 Sb 0.9 2Se3 (containing 3g Sn, 27.4g Sb, and 29.6g Se) was prepared as a target for magnetron sputtering. A hole transport layer was formed on an Ag (150nm) / ITO (15nm) electrode using magnetron sputtering. The RF sputtering power was 70W, the sputtering rate was 2nm / min, the sputtering pressure was 1Pa, the Ar gas flow rate was 10sccm, the sputtering time was 15min, and the film thickness was 25nm.

[0143] (3) Fabrication of quantum dot light-emitting layer

[0144] CdS / ZnSe nanoparticles with a particle size of approximately 12 nm were dissolved in chloroform solvent at a concentration of 10 mg / ml, and 9 drops were printed on the hole transport layer and dried; the film thickness was approximately 20 nm.

[0145] (4) Preparation of electron transport layer (AgSbSe2 / Sb2Se3 material):

[0146] Add 24 mmol SeO2 and 30 mL of organic solvent octadecene (ODE), stir and heat to 200 °C, keep warm for 5 h, SeO2 completely dissolves, and 0.8 mol / L Se-ODE precursor solution is obtained;

[0147] 1.2 mmol Sb(CH3COO)3, 8 mmol hexadecylacrylamide (HDA), 15 mL ODE and 6 mL oleic acid (OA) were added to a flask, stirred and heated to 220 °C under a nitrogen atmosphere, and kept at this temperature for 1 h to obtain the antimony precursor solution.

[0148] 1.84 mL of Se-ODE precursor solution was added to antimony precursor solution and reacted at 240 °C for 2 min. Then 0.4 mmol of CH3COOAg was added and stirred for 3 min. Then 6 mL of Se-ODE precursor solution was added and reacted for 10 min to obtain AgSbSe2 / Sb2Se3 heterojunction nanorods with a mass ratio of AgSbSe2 to Sb2Se3 of approximately 0.4:1.

[0149] AgSbSe2 / Sb2Se3 heterojunction nanorods were prepared into 20 mg / mL ink, and 10 drops were printed on the quantum dot luminescent layer film. After drying, the thickness was about 30 nm, which is the electron transport layer film.

[0150] (5) Stacked cathodes.

[0151] (6) Packaging.

[0152] Comparative Example 1

[0153] Traditional hole transport layer and electron transport layer materials are used; the specific structure is Ag (140nm) / ITO (15nm) / TFB (25nm) / RQD (20nm) / ZnO (30nm) / Ag (20nm).

[0154] Comparative Example 2

[0155] The specific structure of a quantum dot light-emitting diode is: substrate / anode [(Ag, 150nm) / ITO, 15nm)] / hole transport layer (Sn) 0.1 Sb 0.9 )2Se3, 25nm) / Light-emitting layer (CdS / ZnSe, 20nm) / Electron transport layer (TiSbSe / Sb2Se3, 30nm) / Cathode (silver, 20nm) / Encapsulation layer.

[0156] (1) Provide an Ag(150nm) / ITO(15nm) electrode, which is the anode, formed on the substrate;

[0157] (2) Preparation of hole transport layer

[0158] 60g (Sn)0.1 Sb 0.9 2Se3 (containing 3g Sn, 27.4g Sb, and 29.6g Se) was prepared as a target for magnetron sputtering. A hole transport layer was formed on an Ag (150nm) / ITO (15nm) electrode using magnetron sputtering. The RF sputtering power was 70W, the sputtering rate was 2nm / min, the sputtering pressure was 1Pa, the Ar gas flow rate was 10sccm, the sputtering time was 15min, and the film thickness was 25nm.

[0159] (3) Fabrication of quantum dot light-emitting layer

[0160] CdS / ZnSe nanoparticles with a particle size of approximately 12 nm were dissolved in chloroform solvent at a concentration of 10 mg / ml, and 9 drops were printed on the hole transport layer and dried; the film thickness was approximately 20 nm.

[0161] (4) Fabrication of electron transport layer

[0162] Preparation of TiSbSe / Sb2Se3 materials:

[0163] Add 24 mmol SeO2 and 30 mL of organic solvent octadecene (ODE), stir and heat to 200 °C, keep warm for 5 h, SeO2 completely dissolves, and 0.8 mol / L first precursor solution is obtained;

[0164] 2 mmol Ti(CH3COO), 8 mmol hexadecylacrylamide (HDA), 15 mL ODE and 6 mL oleic acid (OA) were added to a flask, stirred and heated to 250 °C under a nitrogen atmosphere, and kept at this temperature for 1 h to obtain the second precursor solution.

[0165] 2 mL of the first precursor solution was added to the second precursor solution and reacted at 250 °C for 2 min. Then 0.4 mmol was added and stirred for 3 min. Then 6 mL of the first precursor solution was added and reacted for 10 min to obtain TiSbSe2 / Sb2Se3 heterojunction nanorods with a mass ratio of TiSbSe2 to Sb2Se3 of approximately 0.46:1.

[0166] TiSbSe2 / Sb2Se3 heterojunction nanorods were prepared into 20 mg / mL ink, and 10 drops were printed on the quantum dot luminescent layer film. After drying, the thickness was about 30 nm, which is the electron transport layer film.

[0167] Comparative Example 3

[0168] The specific structure of a quantum dot light-emitting diode is: substrate / anode [(Ag, 150nm) / ITO, 15nm)] / hole transport layer (Sn) 0.1 Sb 0.9(2S3, 25nm) / Light-emitting layer (CdS / ZnSe, 20nm) / Electron transport layer (AgSbSe2 / Sb2Se3, 30nm) / Cathode (silver, 20nm) / Encapsulation layer.

[0169] (1) Provide an Ag(150nm) / ITO(15nm) electrode, which is the anode, formed on the substrate;

[0170] (2) Preparation of hole transport layer

[0171] 60g (Sn) 0.1 Sb 0.9 2S3 (containing 4.2 g Sn, 38.8 g Sb, and 17 g S) was prepared as a target for magnetron sputtering. A hole transport layer was formed on the Ag (150 nm) / ITO (15 nm) substrate electrode using magnetron sputtering. The RF sputtering power was 70 W, the sputtering rate was 2 nm / min, the sputtering pressure was 1 Pa, the Ar gas flow rate was 10 sccm, the sputtering time was 15 min, and the film thickness was 25 nm.

[0172] (3) Fabrication of quantum dot light-emitting layer

[0173] CdS / ZnSe nanoparticles with a particle size of approximately 12 nm were dissolved in chloroform solvent at a concentration of 10 mg / ml, and 9 drops were printed on the hole transport layer and dried; the film thickness was approximately 20 nm.

[0174] (4) Preparation of electron transport layer (AgSbSe2 / Sb2Se3 material):

[0175] Add 24 mmol SeO2 and 30 mL of organic solvent octadecene (ODE), stir and heat to 200 °C, keep warm for 5 h, SeO2 completely dissolves, and 0.8 mol / L Se-ODE precursor solution is obtained;

[0176] 1.2 mmol Sb(CH3COO)3, 8 mmol hexadecylacrylamide (HDA), 15 mL ODE and 6 mL oleic acid (OA) were added to a flask, stirred and heated to 220 °C under a nitrogen atmosphere, and kept at this temperature for 1 h to obtain the antimony precursor solution.

[0177] 2 mL of Se-ODE precursor solution was added to antimony precursor solution and reacted at 240 °C for 2 min. Then 0.4 mmol of CH3COOAg was added and stirred for 3 min. Then 6 mL of Se-ODE precursor solution was added and reacted for 10 min to obtain AgSbSe2 / Sb2Se3 heterojunction nanorods with a mass ratio of AgSbSe2 to Sb2Se3 of 0.25:1.

[0178] AgSbSe2 / Sb2Se3 heterojunction nanorods were prepared into 20 mg / mL ink, and 10 drops were printed on the quantum dot luminescent layer film. After drying, the thickness was about 30 nm, which is the electron transport layer film.

[0179] (5) Stacked cathodes.

[0180] (6) Packaging.

[0181] The materials of the hole transport layer and electron transport layer in Examples 1-5 and Comparative Examples 1-3 are shown in Table 1.

[0182] Table 1

[0183]

[0184] The conductivity of the electron transport layer films prepared in the examples and comparative examples was tested using commonly used testing methods in the art. The EQE, brightness, and LT95@1000nit of the display devices prepared in the examples and comparative examples were also tested. The testing standards were as follows:

[0185] EQE: Represents the external quantum efficiency of a device, which is the proportion of excitons converted into photons and emitted. The higher the proportion, the higher the device efficiency.

[0186] Brightness: The brightness value is obtained by using a luminance meter under fixed voltage conditions. Here, the brightness of the comparison device is used under a fixed voltage of 3V.

[0187] LT95@1000nit: This refers to the time required for a device to decay from 1000nit brightness to 950nit brightness, representing the device's lifetime.

[0188] The results are shown in Table 2.

[0189] Table 2

[0190]

[0191]

[0192] As shown in Table 2, for the hole transport layer, doping the metal selenide with specific elements can promote carrier transport and improve device efficiency. The higher the doping ratio of the p-type dopant within a certain range, the better the carrier transport and the higher the device efficiency. In the electron transport layer, the higher the mass ratio of the second metal selenide to the first metal selenide, the better the material conductivity. The synergistic effect of the two promotes the stability of the device.

[0193] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0194] The embodiments described above are merely illustrative of several implementations of the present invention, designed to facilitate a detailed understanding of the technical solutions of the present invention, but should not be construed as limiting the scope of protection of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the scope of protection of the present invention. It should be understood that technical solutions obtained by those skilled in the art based on the technical solutions provided by the present invention through logical analysis, reasoning, or limited experimentation are all within the scope of protection of the appended claims. Therefore, the scope of protection of this invention patent should be determined by the content of the appended claims, and the specification and drawings can be used to interpret the content of the claims.

Claims

1. A display device, characterized in that, include: The anode, hole transport layer, quantum dot light-emitting layer, electron transport layer and cathode are stacked in sequence. The electron transport layer comprises heterojunction nanomaterials, which include: A first metal selenide and a second metal selenide composited on the first metal selenide, wherein the second metal selenide is a silver-doped metal selenide, and a heterojunction is formed between the first metal selenide and the second metal selenide; The hole transport layer comprises a third metal selenide.

2. The display device as claimed in claim 1, characterized in that, The first metal selenide is a nanorod, and the second metal selenide is nanoparticles distributed on the surface of the first metal selenide.

3. The display device as described in claim 2, characterized in that, The diameter of the first metal selenide is 20 nm to 30 nm, and the length is 1000 nm to 2000 nm; And / or, the particle size of the second metal selenide is 10 nm to 20 nm.

4. The display device as described in claim 3, characterized in that, The diameter of the first metal selenide is 20 nm to 25 nm, and the length is 1000 nm to 1500 nm; And / or, the particle size of the second metal selenide is 10 nm to 15 nm.

5. The display device according to any one of claims 1 to 4, characterized in that, The first metal selenide is selected from at least one of SnSe, Sb2Se3, In4Se3, ZnSe, MoSe2 and WSe2; And / or, the second metal selenide is selected from at least one of AgSnSe, AgSbSe2, AgIn3Se3, AgZnSe, AgMoSe2 and AgWSe2.

6. The display device according to any one of claims 1 to 4, characterized in that, The mass ratio of the second metal selenide to the first metal selenide is (0.2~0.5):

1.

7. The display device as claimed in claim 6, characterized in that, The mass ratio of the second metal selenide to the first metal selenide is (0.25~0.43):

1.

8. The display device according to any one of claims 1 to 4, 7, characterized in that, The third metal selenide is a P-type doped metal selenide.

9. The display device as claimed in claim 8, characterized in that, The P-type doped element is selected from at least one of Sn, Zn and Mo.

10. The display device as claimed in claim 9, characterized in that, The metal selenide in the third metal selenide is selected from at least one of SnSe, Sb2Se3, In4Se3, ZnSe, MoSe2 and WSe2, wherein the p-type doped element is different from the element contained in the metal selenide in the third metal selenide.

11. The display device as claimed in claim 8, characterized in that, The general formula of the p-type doped metal selenide is (Sn x Sb 1-x )2Se3; where 0 < x < 0.

9.

12. The display device according to any one of claims 1 to 4, 7, 9 to 11, characterized in that, The anode material is selected from at least one of indium tin oxide, indium zinc oxide, and aluminum-doped zinc oxide; And / or, the material of the quantum dot light-emitting layer is selected from at least one of CdS, ZnSe and CdZnS; And / or, the cathode material is selected from at least one of Ag, Au, Al and Cu.

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