WO2022016820A1 - Quantum dot light-emitting diode and preparation method therefor - Google Patents

Abstract

A quantum dot light-emitting diode and a preparation method therefor. The preparation method comprises the following steps: providing an anode substrate, said anode substrate being provided with a hole functional layer, the material of the hole functional layer being a benzyl-containing organic material (S01); preparing on the surface of the hole functional layer a quantum dot light-emitting layer containing quantum dots and a crosslinking agent, and performing ultraviolet illumination to perform a crosslinking reaction (S02); or, providing a cathode substrate, said cathode substrate being provided with a quantum dot light-emitting layer containing quantum dots and a crosslinking agent (E01); preparing on the surface of the quantum dot light-emitting layer a hole functional layer, and performing ultraviolet illumination so as to perform a crosslinking reaction, wherein the material of the hole functional layer is a benzyl-containing organic material (E02). The preparation method stabilizes the interface contact between the quantum dot light-emitting layer and the hole functional layer, and reduces the non-radiative recombination caused by interface defects, thereby improving the electro-optical efficiency and service life of a component.

Description

Quantum dot light-emitting diode and preparation method thereof

This application claims the priority of the Chinese patent application with the application number of 202010709910.2 and the invention title "Quantum Dot Light Emitting Diode and its Preparation Method", which was filed with the China Patent Office on July 22, 2020, the entire contents of which are incorporated by reference in in this application.

technical field

The present application relates to the technical field of display devices, in particular to a quantum dot light-emitting diode and a preparation method thereof.

Background technique

Quantum Dot (QD) has the characteristics of wide excitation spectrum, narrow emission spectrum and symmetry. The peak position of the luminescence spectrum can be adjusted by changing its size, and the emission spectrum can be covered by changing the size and chemical composition of the quantum dot. to the entire visible light region; in addition, the manufacturing price of quantum dot light-emitting diodes (Quantum Dot Light Emitting Diode, QLED) is relatively lower than that of organic light-emitting diodes (Organic Light Emitting Diodes). Emitting Diode, OLED). Therefore, quantum dot light-emitting diodes are considered to be the most promising technology in the future solid-state lighting industry.

Common QLED devices generally have both forward and reverse structures. Whether it is a device with a forward or reverse structure, a hole transport layer and an electron transport layer can be provided on both sides of the quantum dot light-emitting layer. The layer materials are mostly inorganic nano-ions, which generally have high carrier mobility, and the interface contact barrier between electrodes is small, resulting in stronger electron injection and transport capabilities than hole transport materials. Therefore, in QLED devices, The main reason for the low electro-optical efficiency is due to the unbalanced charge injection. When there is an excess of electrons in the device, on the one hand, the electrons will pass through the QD light-emitting layer to the hole transport layer, resulting in the recombination of exciton radiation outside the QD light-emitting layer. On the other hand, the excess electrons will accumulate in the QD light-emitting layer. , resulting in quantum dots with dots and increasing the Auger recombination rate; so balancing the carrier injection efficiency of electrons and holes is the main way to improve the performance of quantum dot light-emitting diodes. In the existing technical solution, the forbidden band width is adjusted by doping Mg in the electron transport layer material such as ZnO, and the electron injection barrier is increased, so as to achieve the injection balance of electrons and holes. However, the relatively large energy level difference between the hole transport layer and the quantum dot light-emitting layer will block the injection of holes, and poor interfacial contact will still lead to an imbalance in the injection rates of electrons and holes, resulting in device efficiency and Lifespan is low.

Therefore, the related technology needs to be improved.

technical problem

The purpose of the embodiments of the present application is to provide a quantum dot light-emitting diode and a preparation method thereof, aiming at solving the technical problem that the interface contact between the quantum dot light-emitting layer and the hole functional layer of the existing quantum dot diode is not ideal, thereby causing interface defects .

technical solutions

In order to solve the above-mentioned technical problems, the technical solutions adopted in the embodiments of the present application are:

In a first aspect, the present application provides a method for preparing a quantum dot light-emitting diode, comprising the following steps:

An anode substrate is provided, a hole functional layer is provided on the anode substrate, and the material of the hole functional layer is an organic material containing a benzyl group;

A quantum dot light-emitting layer containing quantum dots and a cross-linking agent is prepared on the surface of the hole functional layer, and then the cross-linking reaction is carried out by ultraviolet light;

or,

A cathode substrate is provided, and a quantum dot light-emitting layer containing quantum dots and a cross-linking agent is provided on the cathode substrate;

A hole functional layer is prepared on the surface of the quantum dot light-emitting layer, and then cross-linking reaction is performed by ultraviolet light; wherein, the material of the hole functional layer is an organic material containing a benzyl group.

In a second aspect, the present application provides a quantum dot light-emitting diode, comprising an anode, a cathode, and a quantum dot light-emitting layer located between the anode and the cathode, and a quantum dot light-emitting layer is disposed between the anode and the quantum dot light-emitting layer A hole function layer; the material of the hole function layer is an organic material containing benzyl groups, the quantum dot light-emitting layer contains quantum dots and a crosslinking agent, and the quantum dot light-emitting layer and the hole function layer interface cross-linked.

beneficial effect

The beneficial effect of the preparation method of the quantum dot light-emitting diode provided by the embodiment of the present application is that when the quantum dot light-emitting diode prepares the adjacent hole functional layer and the quantum dot light-emitting layer, the material of the hole functional layer is a benzyl group-containing organic Materials, the material of the quantum dot light-emitting layer includes quantum dots and a cross-linking agent, so that during the ultraviolet irradiation process, at the interface between the quantum dot light-emitting layer and the hole functional layer, the cross-linking agent and the organic material containing benzyl groups will occur. Specifically, the cross-linking agent reacts with benzyl hydrogen to form stable free radicals, and the cross-linking reaction is carried out through free radical coupling, so as to stabilize the interface contact between the quantum dot light-emitting layer and the hole functional layer, which can reduce interface defects The resulting non-radiative recombination improves the electro-optical efficiency and lifetime of quantum dot light-emitting diodes.

The beneficial effect of the quantum dot light-emitting diode provided by the embodiments of the present application is that the quantum dot light-emitting diode can stabilize the interface contact between the quantum dot light-emitting layer and the hole functional layer, thereby reducing the non-radiative recombination caused by interface defects, and improving the quantum dot light-emitting diode. electro-optical efficiency and lifetime.

Description of drawings

In order to illustrate the technical solutions in the embodiments of the present application more clearly, the following briefly introduces the accompanying drawings that are used in the description of the embodiments or exemplary technologies. Obviously, the drawings in the following description are only for the present application. In some embodiments, for those of ordinary skill in the art, other drawings can also be obtained according to these drawings without any creative effort.

1 is a schematic flow chart of a method for preparing a quantum dot light-emitting diode with an upright structure of the present application;

2 is a schematic flowchart of a method for preparing a quantum dot light-emitting diode with an inverted structure of the present application;

3 is a schematic structural diagram of a quantum dot light-emitting diode with an upright structure of the present application;

Fig. 4 is the device electroluminescence spectrogram of Example 1, Example 2 and Comparative Example 1;

5 is a graph of the current efficiency of the quantum dot light-emitting diode device of Example 1;

6 is a graph of the current efficiency of the quantum dot light-emitting diode device of Example 2;

7 is a graph of the current efficiency of the quantum dot light-emitting diode device of Comparative Example 1;

FIG. 8 is a graph of device life test curves of Example 1, Example 2 and Comparative Example 1. FIG.

Embodiments of the present invention

In order to make the purpose, technical solutions and advantages of the present application more clearly understood, the present application will be described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application, but not to limit the present application.

On the one hand, some embodiments of the present application provide a preparation method of a quantum dot light-emitting diode. When the quantum dot light-emitting diode is a quantum dot light-emitting diode with an upright structure, as shown in FIG. 1 , the preparation method includes the following steps:

S01: Provide an anode substrate, the anode substrate is provided with a hole functional layer, and the material of the hole functional layer is an organic material containing a benzyl group;

S02: prepare a quantum dot light-emitting layer containing quantum dots and a cross-linking agent on the surface of the hole functional layer, and then perform a cross-linking reaction with ultraviolet light.

Alternatively, when the quantum dot light-emitting diode is a quantum dot light-emitting diode with an inverted structure, as shown in FIG. 2 , the preparation method includes the following steps:

E01: Provide a cathode substrate, on which a quantum dot light-emitting layer containing quantum dots and a cross-linking agent is provided;

E02: Prepare a hole functional layer on the surface of the quantum dot light-emitting layer, and then perform a cross-linking reaction with ultraviolet light; wherein, the material of the hole functional layer is an organic material containing a benzyl group.

In the preparation method of the quantum dot light-emitting diode provided in the embodiment of the present application, whether it is an upright structure or an inverted structure, when preparing the adjacent hole function layer and the quantum dot light-emitting layer, the material of the hole function layer is a material containing Benzyl-based organic materials, quantum dot light-emitting layer materials include quantum dots and cross-linking agents, so that in the process of ultraviolet irradiation, at the interface between the quantum dot light-emitting layer and the hole functional layer, the cross-linking agent and benzyl-containing organic materials. The material will undergo a cross-linking reaction. Specifically, the cross-linking agent reacts with benzyl hydrogen to form a stable free radical, and the cross-linking reaction is carried out through free radical coupling, so as to stabilize the interface contact between the quantum dot light-emitting layer and the hole functional layer, so that The non-radiative recombination caused by interface defects can be reduced, thereby improving the electro-optical efficiency and lifetime of quantum dot light-emitting diodes.

For QLED devices, in the upright structure or the inverted structure, the quantum dot light-emitting layer and the hole functional layer are formed into adjacent deposited film layers by spin coating, blade coating, printing, spraying and other film forming processes. The hole is transported to the quantum dot light-emitting layer through the hole functional layer. The interface contact quality and defects of the quantum dot light-emitting layer film and the hole functional layer film will affect the non-radiative recombination probability of excitons, and the current efficiency and lifetime of the QLED device. Great impact. Quantum dots are inorganic nano-quantum dot materials, and the hole functional layer is generally an organic polymer material. If the interface between the two is not in good contact, the hole injection efficiency will be low, resulting in a more unbalanced injection of electrons and holes in QLED devices. serious, thereby reducing the electro-optical efficiency and life of the light-emitting diode device. In the embodiment of the present application, in order to obtain better interface contact between the quantum dot light-emitting layer and the hole functional layer film, reduce interface defects, and improve the rate of hole carriers injected into the quantum dot light-emitting layer, the quantum dot material is used in the quantum dot material. Doping the cross-linking agent, after the quantum dot light-emitting layer thin film is prepared in this way, the cross-linking agent doped in the quantum dot light-emitting layer and the organic material containing benzyl groups in the hole functional layer are freed at the interface by means of ultraviolet light. Base coupling cross-linking reaction, thus forming the interface between the quantum dot light-emitting layer and the hole functional layer in close contact.

In some embodiments, the cross-linking agent in the quantum dot light-emitting layer is selected from at least one of benzophenone and benzophenone derivatives. Specifically, the cross-linking agent may be benzophenone, or It is a benzophenone derivative or a combination of benzophenone and benzophenone derivatives. In the embodiment of the present application, a certain proportion of benzophenone and benzophenone derivatives are doped in the quantum dot light-emitting layer, and the above-mentioned benzophenone and benzophenone derivatives are combined with the hole functional layer under the condition of ultraviolet light. The highly active benzyl hydrogen on the surface reacts, and after the reaction, stable free radicals can be formed, and the free radicals are coupled and cross-linked to form a stable interface contact between the quantum dot light-emitting layer and the hole functional layer, which can reduce the undesired effects of interface defects. Radiation recombination, thereby improving the electro-optical efficiency and lifetime of quantum dot light-emitting diodes. Further, the benzophenone derivative is selected from 2,4-dinitrobenzophenone, 2-hydroxy-4-methoxybenzophenone and 2-hydroxy-4-n-octyloxydiphenone At least one of the benzophenones, specifically, can be 2,4-dinitrobenzophenone, or 2-hydroxy-4-methoxybenzophenone, or 2-hydroxy-4-normal Octyloxybenzophenone, or 2,4-dinitrobenzophenone, 2-hydroxy-4-methoxybenzophenone and 2-hydroxy-4-n-octyloxybenzophenone above A combination of two or three of the ketones. The quantum dots in the above-mentioned quantum dot light-emitting layer include at least one of II-VI, IV-VI, III-V, I-VI group compound single structure and composite structure quantum dots, and the composite structure quantum dot includes a core-shell structure Quantum dots, the cores constituting the core-shell quantum dots include CdSe, CdS, CdTe, CdSeTe, CdZnS, PbSe, ZnTe, CdSeS, PbS, PbTe, HgS, HgSe, HgTe, GaN, GaP, GaAs, InP, InAs, At least one of InZnP, InGaP and InGaN; the shell constituting the core-shell structure quantum dot contains at least one of ZnSe, ZnS and ZnSeS.

In some embodiments, the benzyl-containing organic material of the hole functional layer is selected from poly(9-vinylcarbazole), poly[(9,9-di-n-octylfluorenyl-2,7-di base)-alt-(4,4′-(N-(4-n-butyl)phenyl)-diphenylamine)] (TFB), poly[(9,9-di-n-octylfluorenyl-2,7 -Phenyleneethylene)-alt-(2-methoxy-5-(2-ethylhexyloxy)-1,4diyl)], poly(9,9-dioctylfluorene-2, 7-diyl)-alt-(N,N'-diphenylbenzidine-N,N'-diyl), poly(9,9-di-n-octylfluorenyl-2,7-diyl), Poly[(N,N'-(4-n-butylphenyl)-N,N'-diphenyl-1,4-phenylenediamine)-alt-(9,9-di-n-octylfluorenyl- 2,7-diyl)], poly[9-(1-octylnonyl)-9H-carbazole], poly[2-methoxy-5-(2-ethylhexyloxy)-1,4- Phenylacetylene], poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylacetylene], poly[(9,9-dioctylfluorenyl-2,7-di yl)-co-thiophene] and poly[(9,9-dioctylfluorenyl-2,7-diyl)-alt-(benzo[2,1,3]thiadiazole-4,8- At least one of the benzyl group)], for example, may be one of the above-mentioned benzyl group-containing organic materials, or a combination of two or three thereof. The hole function layer can be a hole transport layer, and the hole function material not only contains a benzyl group, can be cross-linked with benzophenone or a benzophenone derivative, but also has good hole transport performance.

For the preparation method of a quantum dot light-emitting diode with an upright structure, the step of preparing a quantum dot light-emitting layer containing quantum dots and a cross-linking agent on the surface of the hole functional layer includes: mixing a mixture containing the cross-linking agent and the hole functional material The solution is deposited on the surface of the hole functional layer and then annealed.

In some embodiments, the mixed solution containing the cross-linking agent and quantum dots is formulated by dissolving the above-mentioned cross-linking agent and quantum dot material in a solvent. Wherein, the concentration of the quantum dot material in the mixed solution is 10-50mg/ml, specifically, the concentration of the quantum dot material can be 10mg/ml, 20mg/ml, 30mg/ml, 40mg/ml, 50mg/ml ml, etc., the quantum dot material dispersion effect is better within the above concentration range; the mass ratio of the crosslinking agent and the quantum dot material in the mixed solution is (0.5-5): 100, specifically, the crosslinking agent The mass ratio of the quantum dot material can be 0.5:100, 1:100, 2:100, 4:100, 5:100, etc. When the proportion of the crosslinking agent is too low, the quantum dot light-emitting layer and hole functional layer If the crosslinking agent component at the interface is too small, it is difficult to fully crosslink with the hole functional layer material, and the interface contact effect is not good; Conductive cross-linking agent, although excessive cross-linking agent is beneficial to cross-linking, it will increase the difficulty of electron and hole injection and transport in the quantum dot light-emitting layer, and reduce the probability of the radiative recombination of carriers in the quantum dot light-emitting layer. Therefore, the quantum dot light-emitting layer formed by the crosslinking agent and the quantum dot material within the above ratio range can not only obtain a good interface morphology, but also improve the electro-optical efficiency and lifetime performance of the QLED device.

Further, the solvent in the mixed solution is selected from non-polar solvents such as hydrocarbon solvents. Specifically, the hydrocarbon solvent is selected from at least one of saturated or unsaturated alkanes and saturated or unsaturated aromatic hydrocarbons. The mixed solution dispersed with the cross-linking agent and quantum dots is deposited on the surface of the hole functional layer, and annealed to remove the solvent, and then cross-linked with the benzyl-containing organic material on the surface of the hole functional layer under the condition of ultraviolet light to form a stable solution. interface contact.

In some embodiments, the method of depositing the mixed solution containing the crosslinking agent and the quantum dots on the surface of the hole functional layer includes spin coating, blade coating, printing, spray coating, and the like. The subsequent annealing process can be performed in an anhydrous and oxygen-free environment.

In some embodiments, the temperature of the annealing treatment is 50-250°C, for example, the temperature of the annealing treatment may be 50°C, 80°C, 100°C, 150°C, 200°C, 250°C, etc.; The temperature is 10-30min, for example, the time of annealing treatment can be 10min, 15min, 20min, 25min, 30min, etc. The film-forming effect is better under the above annealing conditions.

In some embodiments, the wavelength of the ultraviolet light is 200-410nm, such as 200nm, 250nm, 300nm, 400nm, etc.; the time of the ultraviolet light is 5-15min, such as 5min, 10min, 15min; the above-mentioned ultraviolet light conditions Under 200-410nm ultraviolet light, the carbonyl group on benzophenone and benzophenone derivatives reacts with the highly active benzyl hydrogen on the hole functional layer material, and the reaction After that, stable free radicals can be formed, and the generated free radicals can undergo a cross-linking reaction through free radical coupling, thereby obtaining a quantum dot light-emitting layer and a hole functional group layer film with closely adjacent interfaces.

When the substrate is an anode substrate, step S02: preparing a quantum dot light-emitting layer containing quantum dots and a cross-linking agent on the surface of the hole functional layer, and then performing a cross-linking reaction with ultraviolet light, and also including the quantum dot light-emitting layer on the surface of the hole functional layer. Prepare the cathode. The quantum dot light-emitting diode thus obtained comprises an anode, a cathode and a quantum dot light-emitting layer between the anode and the cathode, and a hole functional layer is arranged between the anode and the quantum dot light-emitting layer; the material of the hole functional layer is benzyl-containing The organic material of the quantum dot light-emitting layer contains quantum dots and a cross-linking agent, and the quantum dot light-emitting layer and the hole functional layer interface are cross-linked. Further, after preparing the electronic functional layer on the quantum dot light-emitting layer, the cathode is prepared.

In some embodiments, the mixed solution further contains a high molecular polymer, and the temperature of the annealing treatment is greater than or equal to the glass transition temperature of the high molecular polymer.

Deposit a mixed solution containing a crosslinking agent, quantum dots and a high molecular polymer on the surface of the above hole functional layer, and perform annealing treatment to obtain a quantum dot light-emitting layer, because in the process of the annealing treatment, the temperature of the annealing treatment is greater than or equal to the polymer polymerization. Specifically, when the temperature of the annealing treatment is equal to the glass transition temperature of the polymer, the polymer is in a highly elastic state, and when the temperature of the annealing treatment is greater than the glass transition temperature of the polymer When the temperature is high, the polymer is in a viscous fluid state, and the above conditions can make the molecular structure of the polymer more relaxed, so that the positions of the quantum dots in the quantum dot light-emitting layer are rearranged, and the polymer is densely packed and compacted. The arrangement is regular to form a flat quantum dot film; at the same time, under the condition of subsequent ultraviolet irradiation, the cross-linking reaction is carried out with the organic material containing the benzyl group on the surface of the hole functional layer to form a stable interface contact, and the quantum dot obtained by this preparation method emits light. layers can significantly improve the electro-optical efficiency and lifetime of the device.

In some embodiments, the high molecular polymer is selected from at least one of vinyl-based polymers, acryl-based polymers, amide-based polymers, phenyl-based polymers and carbonate-based polymers, for example , which can be vinyl-based polymers, or propylene-based polymers, or amide-based polymers, or phenyl-based polymers, or carbonate-based polymers, or one or both of the above-mentioned polymers etc combination. From the above macromolecular polymers, select a suitable glass transition temperature (≤ annealing temperature) and mix with quantum dots and crosslinking agent materials to prepare a quantum dot light-emitting layer.

Specifically, the vinyl-based polymer is selected from at least one of polyvinyl alcohol, polyvinyl carbazole, polyvinyl acetate, polytetrafluoroethylene, polyvinylidene fluoride and polyvinyl chloride; the propylene The base polymer is selected from at least one of polyacrylic acid, polymethyl methacrylate, poly(α-butyl nitrile acrylate), polyacrylamide and polyacrylonitrile; the amide polymer is selected from polyamide At least one of decyl formamide and polyethylene sebacate; the phenyl-based polymer is selected from at least one of polyphenylene sulfide and polyethylene terephthalate; the carbonate The quasi-polymer is selected from at least one of polycarbonate diol and brominated polycarbonate.

In some embodiments, the glass transition temperature of the high-molecular polymer is 30-200° C.; the temperature of the annealing treatment is 50-250° C., and the temperature of the annealing treatment is greater than or equal to the glass transition temperature of the high-molecular polymer . Further, preferably, the glass transition temperature is selected to be in the range of 50-150°C, and the temperature of the annealing treatment is 120-180°C. The low glass transition temperature enables low-temperature annealing and has little effect on the thermal aging of the device. For example, the glass transition temperature of polymethyl methacrylate is 105°C, and the annealing temperature can be selected to be ≥105°C. The glass transition temperature of polytetrafluoroethylene is 130°C, so the annealing temperature can be selected to be ≥130°C; the glass transition temperature of polyacrylamide is 165°C, and the annealing temperature to be selected is ≥165°C.

In some embodiments, the mixed solution containing the cross-linking agent, quantum dots and high molecular polymer is prepared by dissolving the above-mentioned cross-linking agent, quantum dots and high molecular polymer in a solvent. Wherein, the concentration of the quantum dots in the mixed solution is 10-50mg/ml, and specifically, the concentration of the quantum dot material can be 10mg/ml, 20mg/ml, 30mg/ml, 40mg/ml, 50mg/ml etc., the dispersion effect of quantum dots is better at this concentration; the mass ratio of the high molecular polymer and the quantum dots in the mixed solution is (0.5-10): 100, specifically, the high molecular polymer and quantum The mass ratio of the dot material can be 0.5:100, 1:100, 4:100, 5:100, 10:100, etc. Under this mass ratio, the quantum dots can be better stacked and arranged into regular quantum dots Point film.

For the preparation method of quantum dot light-emitting diode with inverted structure, the step of preparing a quantum dot light-emitting layer containing quantum dots and a cross-linking agent on a cathode substrate includes: depositing a mixed solution containing a cross-linking agent and quantum dots on the cathode substrate , perform annealing treatment. The preparation of the specific mixed solution and the annealing conditions are the same as the preparation method of the quantum dot light-emitting diode with the vertical structure.

Further, in some embodiments, the mixed solution further contains a high-molecular polymer, and the temperature of the annealing treatment is greater than or equal to the glass transition temperature of the high-molecular polymer. Specifically, a mixed solution containing a cross-linking agent, quantum dots and a high molecular polymer is deposited on the cathode substrate, and annealed to obtain a quantum dot light-emitting layer, because during the annealing process, the annealing temperature is greater than or equal to the polymer The glass transition temperature of the polymer, specifically, when the temperature of the annealing treatment is equal to the glass transition temperature of the polymer, the polymer has a high elastic state, and when the temperature of the annealing treatment is greater than the glass transition temperature of the polymer At the transition temperature, the polymer is in a viscous fluid state. All the above conditions can make the molecular structure of the polymer more relaxed, so that the positions of the quantum dots in the light-emitting layer of the quantum dots are rearranged and packed tightly in the polymer. , and the arrangement is regular to form a flat quantum dot film; at the same time, under the condition of subsequent ultraviolet irradiation, the cross-linking reaction is carried out with the organic material containing the benzyl group on the surface of the hole functional layer to form a stable interface contact. The quantum dots obtained by such a preparation method The light-emitting layer can significantly improve the electro-optical efficiency and lifetime of the device. The selection of high molecular polymers, the specific glass transition temperature and the temperature of annealing treatment, the concentration of quantum dots in the mixed solution, the mass ratio of high molecular polymer and quantum dots can be compared with the preparation of quantum dot light-emitting diodes with upright structure The method is the same.

When the substrate is a cathode substrate, in step E02: preparing a hole functional layer on the surface of the quantum dot light-emitting layer, and then performing a cross-linking reaction with ultraviolet light, further comprising preparing an anode on the hole functional layer. The quantum dot light-emitting diode thus obtained comprises an anode, a cathode and a quantum dot light-emitting layer between the anode and the cathode, and a hole functional layer is arranged between the anode and the quantum dot light-emitting layer; the material of the hole functional layer is benzyl-containing The organic material of the quantum dot light-emitting layer contains quantum dots and a cross-linking agent, and the quantum dot light-emitting layer and the hole functional layer interface are cross-linked. Further, on the cathode substrate, an electronic functional layer and the quantum dot light-emitting layer containing quantum dots and a cross-linking agent are stacked in sequence.

On the other hand, an embodiment of the present application also provides a quantum dot light-emitting diode, comprising an anode, a cathode, and a quantum dot light-emitting layer located between the anode and the cathode, the anode and the quantum dot light-emitting layer are A hole functional layer is arranged between; the material of the hole functional layer is an organic material containing a benzyl group, the quantum dot light-emitting layer contains quantum dots and a cross-linking agent, and the quantum dot light-emitting layer and the hole Functional layer interface cross-linking.

The quantum dot light-emitting diode provided by the embodiment of the present application can stabilize the interface contact between the quantum dot light-emitting layer and the hole functional layer, thereby reducing the non-radiative recombination caused by interface defects, and improving the electro-optical efficiency and life of the quantum dot light-emitting diode.

Specifically, the quantum dot light-emitting diodes described in the embodiments of the present application are prepared by the preparation methods described in the embodiments of the present application. The quantum dot light-emitting diodes provided in the embodiments of the present application are obtained by the unique preparation methods of the embodiments of the present application. Such quantum dot light-emitting diodes can stabilize the interface contact between the quantum dot light-emitting layer and the hole functional layer, thereby reducing the non-radiative recombination caused by interface defects. , to improve the electro-optical efficiency and lifespan of quantum dot light-emitting diodes.

Specifically, the crosslinking agent is selected from at least one of benzophenone and benzophenone derivatives; the benzyl group-containing organic material is selected from poly(9-vinylcarbazole), poly[(( 9,9-Di-n-octylfluorenyl-2,7-diyl)-alt-(4,4′-(N-(4-n-butyl)phenyl)-diphenylamine)], poly[(9 ,9-Di-n-octylfluorenyl-2,7-phenyleneethylene)-alt-(2-methoxy-5-(2-ethylhexyloxy)-1,4diyl)], Poly(9,9-dioctylfluorene-2,7-diyl)-alt-(N,N'-diphenylbenzidine-N,N'-diyl), poly(9,9-dinormal Octylfluorenyl-2,7-diyl), poly[(N,N'-(4-n-butylphenyl)-N,N'-diphenyl-1,4-phenylenediamine)-alt -(9,9-Di-n-octylfluorenyl-2,7-diyl)], poly[9-(1-octylnonyl)-9H-carbazole], poly[2-methoxy-5-( 2-ethylhexyloxy)-1,4-phenylacetylene], poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylacetylene], poly[(9, 9-dioctylfluorenyl-2,7-diyl)-co-thiophene] and poly[(9,9-dioctylfluorenyl-2,7-diyl)-alt-(benzo[2 ,1,3] at least one of thiadiazole-4,8-diyl)]; the mass ratio of the crosslinking agent to the quantum dots is (0.5-5):100. Specifically, the mass ratio of the crosslinking agent and the quantum dot material may be 0.5:100, 1:100, 2:100, 4:100, 5:100, and the like.

Further, the quantum dot light-emitting layer further contains a high molecular polymer, and the annealing temperature when the quantum dot light-emitting layer is annealed to form a film is greater than or equal to the glass transition temperature of the high molecular polymer. Specifically, the mass ratio of the high molecular polymer and the quantum dots is (0.5-10): 100; 4:100, 5:100, 10:100, etc. Further, the high molecular polymer is selected from at least one of vinyl-based polymers, acryl-based polymers, amide-based polymers, phenyl-based polymers and carbonate-based polymers.

In some embodiments, the hole functional layer is a hole transport layer, and the hole functional material is a benzyl group-containing hole transport material.

Further, an electronic functional layer is disposed between the cathode and the quantum dot light-emitting layer. Such as an electron transport layer, or a stacked electron injection layer and electron transport layer, wherein the electron injection layer is adjacent to the cathode.

In a preferred embodiment, the hole functional layer material is selected from poly[(N,N'-(4-n-butylphenyl)-N,N'-diphenyl-1,4-phenylenediamine)- ALT-(9,9-di-n-octylfluorenyl-2,7-diyl)](TFB), a quantum dot light-emitting layer is formed on the hole functional layer, and the preparation solution of the quantum dot light-emitting layer is added with 3 % poly(α-butyl cyanoacrylate) (mass fraction of quantum dots) in green quantum dot solution containing 2% bisbenzophenone (mass fraction of quantum dots), followed by irradiation with a 365nm UV curing lamp After 10 minutes, radical coupling and cross-linking reaction with TFB was carried out to obtain a tightly connected interface layer. After annealing at 100 °C, the positions of quantum dots in the light-emitting layer were rearranged. The prepared device had an external quantum efficiency (EQE) of 18.9% and a lifetime of T95@1000nit. is 1294h.

The quantum dot light-emitting diode provided by the embodiments of the present application includes an upside-down structure and an upside-down structure. The quantum dot light emitting diode with the upright structure is obtained by the preparation method shown in FIG. 1 , and the quantum dot light emitting diode with the inverted structure is obtained by the preparation method shown in FIG. 2 .

In one embodiment, the upright structure quantum dot light-emitting diode comprises a stacked structure of oppositely disposed anode and cathode, a quantum dot light-emitting layer disposed between the anode and the cathode, disposed between the anode and the cathode A hole transport layer between the quantum dot light-emitting layers, and the anode is disposed on the substrate. Further, a hole functional layer such as a hole injection layer and an electron blocking layer can also be arranged between the anode and the quantum dot light-emitting layer; an electron transport layer can also be arranged between the cathode and the quantum dot light-emitting layer. layer, electron injection layer and hole blocking layer and other electronic functional layers. In some upside structure device embodiments, the quantum dot light-emitting diode includes a substrate, an anode disposed on the surface of the substrate, the hole injection layer disposed on the surface of the anode, and the hole injection layer disposed on the surface of the anode. A hole transport layer on the surface of the layer, a quantum dot light-emitting layer provided on the surface of the hole transport layer, an electron transport layer provided on the surface of the quantum dot light-emitting layer, and a cathode provided on the surface of the electron transport layer.

In one embodiment, an inverted-structure quantum dot light-emitting diode includes a stacked structure of an anode and a cathode disposed opposite to each other, a quantum dot light-emitting layer disposed between the anode and the cathode, and disposed between the anode and the cathode. A hole transport layer between the quantum dot light-emitting layers, and the cathode is disposed on the substrate. Further, a hole functional layer such as a hole injection layer and an electron blocking layer can also be arranged between the anode and the quantum dot light-emitting layer; an electron transport layer can also be arranged between the cathode and the quantum dot light-emitting layer. layer, electron injection layer and hole blocking layer and other electronic functional layers. In some embodiments of the inverted structure device, the quantum dot light-emitting diode comprises a substrate, a cathode disposed on the surface of the substrate, the electron transport layer disposed on the surface of the cathode, and an electron transport layer disposed on the surface of the electron transport layer. A quantum dot light-emitting layer, a hole transport layer provided on the surface of the quantum dot light-emitting layer, a hole injection layer provided on the surface of the hole transport layer, and an anode provided on the surface of the hole injection layer.

Substrates include rigid, flexible substrates, specifically glass, silicon wafers, polycarbonate, polymethyl methacrylate, polyethylene terephthalate, polyethylene naphthalate, polyamide, Polyethersulfone, or a combination thereof.

Anodes include metals or alloys thereof such as nickel, platinum, vanadium, chromium, copper, zinc, or gold; conductive metal oxides such as zinc oxide, indium oxide, tin oxide, indium tin oxide (ITO), indium zinc oxide (IZO), or fluorine-doped tin oxide; or a combination of metals and oxides such as ZnO and Al or SnO ₂ and Sb, but not limited thereto, any two or more of the above may be combined.

The hole injection layer includes conductive compounds, including polythiophene, polyaniline, polypyrrole, poly(p-phenylene), polyfluorene, poly(3,4-ethylenedioxythiophene), poly(3,4-ethylenediene) ethyldioxythiophene) polystyrene sulfonate (PEDOT: PSS), MoO ₃ , WoO ₃ , NiO, HATCN, CuO, V ₂ O ₅ , CuS, or a combination thereof.

The benzyl-containing organic material of the hole transport layer is selected from poly(9-vinylcarbazole), poly[(9,9-di-n-octylfluorenyl-2,7-diyl)-alt-(4, 4′-(N-(4-n-butyl)phenyl)-diphenylamine)], poly[(9,9-di-n-octylfluorenyl-2,7-phenylethylene)-alt-( 2-methoxy-5-(2-ethylhexyloxy)-1,4diyl)], poly(9,9-dioctylfluorene-2,7-diyl)-alt-(N, N'-diphenylbenzidine-N,N'-diyl), poly(9,9-di-n-octylfluorenyl-2,7-diyl), poly[(N,N'-(4- n-butylphenyl)-N,N'-diphenyl-1,4-phenylenediamine)-alt-(9,9-di-n-octylfluorenyl-2,7-diyl)], poly[ 9-(1-Octylnonyl)-9H-carbazole], poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylethyne], poly[2-methoxyl -5-(2-ethylhexyloxy)-1,4-phenylacetylene], poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-thiophene] and poly[ At least one of (9,9-dioctylfluorenyl-2,7-diyl)-alt-(benzo[2,1,3]thiadiazole-4,8-diyl)].

The quantum dots in the quantum dot light-emitting layer are group II-VI CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe, CdSeS, CdSeTe, CdSTe, ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, CdZnS, CdZnSe, CdZnTe, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, HgZnTe, CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe, HgZnSTe; or III-V GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, InSb, GaNP, GaNAs, GaNSb, GaPAs, GaPSb, AlNP, AlNAs, AlNSb, AlPAs, AlPSb, InNP, InNAs, InNSb, InPAs, InPSb, GaAlNP, GaAlNAs, GaAlNSb, GaAlPAs, GaAlPSb, GaInNP, GaInNAs, GaInNSb, GaInPAs, GaInPSb, InAlNP, InAlNAs, InAlNSb, InAlPAs, InAlPSb; or SnS, SnSe, SnTe, PbS, PbSe, PbTe, SnSeS, SnSeTe, SnSTe, PbSeS, PbSeTe, PbSTe, SnPbS, SnPbSe, SnPbTe, SnPbSSe, SnPbSeTe, SnPbSTe; or a combination of any one or more of the above.

Wherein, the crosslinking agent in the quantum dot light-emitting layer is selected from at least one of benzophenone and benzophenone derivatives, wherein the benzophenone derivatives are selected from 2,4-dinitrodi At least one of benzophenone, 2-hydroxy-4-methoxybenzophenone, and 2-hydroxy-4-n-octyloxybenzophenone. Further, the quantum dot light-emitting layer also contains a high molecular polymer, and the high molecular polymer is selected from vinyl-based polymers, acryl-based polymers, amide-based polymers, phenyl-based polymers and carbonate-based polymers at least one of them.

The material of the electron transport layer is one or more _{of ZnO, TiO 2} , Alq ₃ , SnO ₂ , ZrO, AlZnO, ZnSnO, BCP, TAZ, PBD, TPBI, Bphen, and CsCO _{3 .}

Cathodes include metals or their alloys such as magnesium, calcium, sodium, potassium, titanium, indium, yttrium, lithium, gadolinium, aluminum, silver, tin, lead, cesium, or barium; multilayer construction materials include alkali metal halides, alkaline earth metals A structure of a first layer of halide, alkali metal oxide, or a combination thereof, and a metal layer, wherein the metal layer comprises an alkaline earth metal, a Group 13 metal, or a combination thereof. For example, LiF/Al, LiO ₂ /Al, LiF/Ca, Liq/Al, and BaF ₂ /Ca, but not limited thereto.

In a specific embodiment, in the upright structure quantum dot light-emitting diode, the anode is selected from indium tin oxide (ITO), the hole injection layer is PEDOT:PSS, the hole transport layer is TFB, and the quantum dot light-emitting layer is doped The red quantum dot material containing 2% bisbenzophenone, the electron transport layer is ZnO, and the cathode is Al.

In a specific embodiment, the thickness of the anode is 20-200 nm; the thickness of the hole injection layer is 20 nm. ~ 200 nm; the thickness of the hole transport layer is 30 ~ 180 nm; the total thickness of the quantum dot light-emitting layer is 30 ~ 180 nm; the thickness of the electron transport layer is 10 ~ 180 nm; the thickness of the cathode is 40 nm ~190 nm.

The application has been subjected to several tests successively, and now a part of the test results are taken as a reference to further describe the application in detail.

Example 1

This embodiment provides a QLED device, the structure of which is shown in FIG. 3 , the QLED device includes a substrate 1 , an anode 2 , a hole injection layer 3 , a hole transport layer 4 , and a quantum dot light-emitting layer 5 in order from bottom to top , electron transport layer 6 , cathode 7 . The material of substrate 1 is glass sheet, the material of anode 2 is ITO substrate, the material of hole injection layer 3 is PEDOT:PSS, the material of hole transport layer 4 is TFB, the material of quantum dot light-emitting layer 5 is CdZnSe /ZnSe/ZnS green quantum dots and bisbenzophenone, the material of the electron transport layer 6 is ZnO, and the material of the cathode 7 is Al.

The preparation method of the device includes the following steps:

A hole injection layer PEDOT:PSS material was spin-coated on the anode ITO, and then annealed at 100 °C for 15 min; then a TFB hole transport layer was formed on the hole injection layer, and annealed at 100 °C for 15 min; A quantum dot light-emitting layer containing bisbenzophenone, poly(α-butyl cyanoacrylate) and CdZnSe/ZnSe/ZnS green quantum dots with a mass ratio of 2:3:100; and irradiated under a 365nm UV lamp for 10min, The bisbenzophenone at the bottom of the quantum dot light-emitting layer and the TFB on the surface of the hole transport layer are subjected to radical coupling for cross-linking reaction; an ethanol solution of ZnO is prepared on the quantum dot light-emitting layer to obtain an electron transport layer; Al cathode electrode layer, encapsulated to form an electroluminescent device.

Example 2

This embodiment provides a QLED device, the structure of which is shown in FIG. 3 , the QLED device includes a substrate 1 , an anode 2 , a hole injection layer 3 , a hole transport layer 4 , and a quantum dot light-emitting layer 5 in order from bottom to top , electron transport layer 6 , cathode 7 . The material of substrate 1 is glass sheet, the material of anode 2 is ITO substrate, the material of hole injection layer 3 is PEDOT:PSS, the material of hole transport layer 4 is TFB, the material of quantum dot light-emitting layer 5 is CdZnSe /ZnSe/ZnS green quantum dots and 2,4-dinitrobenzophenone, the material of the electron transport layer 6 is ZnO, and the material of the cathode 7 is Al.

The preparation method of the device includes the following steps:

A hole injection layer PEDOT:PSS material was spin-coated on the anode ITO, and then annealed at 100 °C for 15 min; then a TFB hole transport layer was formed on the hole injection layer, and annealed at 100 °C for 15 min; The quantum dot light-emitting layer containing 2,4-dinitrobenzophenone and CdZnSe/ZnSe/ZnS green quantum dots with a mass ratio of 1.5:100; 2,4-dinitrobenzophenone and TFB on the surface of the hole transport layer undergo free radical coupling for cross-linking reaction; spin-coat ZnO ethanol solution on the quantum dot light-emitting layer to obtain an electron transport layer; finally, by evaporation Al cathode electrode layer, encapsulated to form an electroluminescent device.

Example 3

This embodiment provides a QLED device, the structure of which is shown in FIG. 3 , the QLED device includes a substrate 1 , an anode 2 , a hole injection layer 3 , a hole transport layer 4 , and a quantum dot light-emitting layer 5 in order from bottom to top , electron transport layer 6 , cathode 7 . The material of the substrate 1 is a glass sheet, the material of the anode 2 is an ITO substrate, the material of the hole injection layer 3 is PEDOT:PSS, the material of the hole transport layer 4 is poly(9-vinylcarbazole), the quantum The material of the point light-emitting layer 5 includes CdZnSe/ZnSe/ZnS green quantum dots and 2-hydroxy-4-methoxybenzophenone, the material of the electron transport layer 6 is ZnO, and the material of the cathode 7 is Al.

The preparation method of the device includes the following steps:

A hole injection layer PEDOT:PSS material was spin-coated on the anode ITO, and then annealed at 100 °C for 15 min; then a poly(9-vinylcarbazole) hole transport layer was formed on the hole injection layer, annealed at 100 °C for 15 min; A quantum dot light-emitting layer containing 2-hydroxy-4-methoxybenzophenone and CdZnSe/ZnSe/ZnS green quantum dots with a mass ratio of 5:100 was formed on the supported hole transport layer; and under a 365 nm UV lamp Irradiate for 10 min, so that the 2-hydroxy-4-methoxybenzophenone at the bottom of the quantum dot light-emitting layer and the poly(9-vinylcarbazole) on the surface of the hole transport layer undergo free radical coupling for cross-linking reaction; An ethanol solution of ZnO is spin-coated on the spot light-emitting layer to obtain an electron transport layer; finally, an electroluminescent device is formed by evaporating an Al cathode electrode layer by encapsulation.

Comparative Example 1

The quantum dot light-emitting diode device of this comparative example is the same as that of Example 1 except that the material of the quantum dot light-emitting layer is only CdZnSe/ZnSe/ZnS green quantum dots.

Comparative Example 2

The quantum dot light-emitting diode device of this comparative example is the same as that of Example 3 except that the material of the quantum dot light-emitting layer is only CdZnSe/ZnSe/ZnS green quantum dots.

Performance Testing

The photoelectric properties and lifespan of the quantum dot light-emitting diode devices of the above examples and comparative examples were tested, and the test results are shown in Table 1 and FIGS. 4-8 .

The life test of the device adopts the 128-channel life test system customized by Guangzhou New Vision Company. The system architecture is to drive the QLED with a constant voltage and constant current source, and test the change of voltage or current; the photodiode detector and test system test the change of the brightness (photocurrent) of the QLED; the luminance meter tests and calibrates the brightness (photocurrent) of the QLED.

Table 1

From the data in Table 1, it can be seen that the quantum dot light-emitting layer of the device in the embodiment of the present application contains benzophenone or benzophenone derivative that can undergo interfacial cross-linking reaction with the hole transport layer in the green quantum dot material used. , which can stabilize the interface contact between the quantum dot light-emitting layer and the hole functional layer, reduce the non-radiative recombination caused by interface defects, and thus improve the electro-optical efficiency and life of the quantum dot light-emitting diode. Compared with Comparative Example 1, Examples 1 and 2 have a nearly 3 times improvement in current efficiency, and due to the optimization of the interface between the quantum dot light-emitting layer and the hole transport layer, the life of the device is improved by 5-8 times; the same conclusion is as follows: The experimental results of Example 3 and Comparative Example 2 are consistent.

The above are only optional embodiments of the present application, and are not intended to limit the present application. Various modifications and variations of this application are possible for those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of this application shall be included within the scope of the claims of this application.

Claims (20)

1. A method for preparing a quantum dot light-emitting diode, comprising the following steps:

   An anode substrate is provided, a hole functional layer is provided on the anode substrate, and the material of the hole functional layer is an organic material containing a benzyl group;

   A quantum dot light-emitting layer containing quantum dots and a cross-linking agent is prepared on the surface of the hole functional layer, and then the cross-linking reaction is carried out by ultraviolet light;

   or,

   A cathode substrate is provided, and a quantum dot light-emitting layer containing quantum dots and a cross-linking agent is provided on the cathode substrate;

   A hole functional layer is prepared on the surface of the quantum dot light-emitting layer, and then cross-linking reaction is performed by ultraviolet light; wherein, the material of the hole functional layer is an organic material containing a benzyl group.
2. The method for preparing a quantum dot light-emitting diode according to claim 1, wherein the crosslinking agent is selected from at least one of benzophenone and benzophenone derivatives.
3. The method for preparing a quantum dot light-emitting diode according to claim 1, wherein the benzyl-containing organic material is selected from the group consisting of poly(9-vinylcarbazole), poly[(9,9-di-n-octyl) Fluorenyl-2,7-diyl)-alt-(4,4′-(N-(4-n-butyl)phenyl)-diphenylamine)], poly[(9,9-di-n-octylfluorene) (2,7-phenylethylene)-alt-(2-methoxy-5-(2-ethylhexyloxy)-1,4diyl)], poly(9,9-dioctyl) Fluorene-2,7-diyl)-alt-(N,N'-diphenylbenzidine-N,N'-diyl), poly(9,9-di-n-octylfluorenyl-2,7 -diyl), poly[(N,N'-(4-n-butylphenyl)-N,N'-diphenyl-1,4-phenylenediamine)-alt-(9,9-di-n-butylphenyl)- Octylfluorenyl-2,7-diyl)], poly[9-(1-octylnonyl)-9H-carbazole], poly[2-methoxy-5-(2-ethylhexyloxy) -1,4-phenylacetylene], poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylacetylene], poly[(9,9-dioctylfluorenyl- 2,7-Diyl)-co-thiophene] and poly[(9,9-dioctylfluorenyl-2,7-diyl)-alt-(benzo[2,1,3]thiadiazole -4,8-diyl)] at least one.
4. The method for preparing a quantum dot light-emitting diode according to claim 1, wherein the wavelength of the ultraviolet light is 200-410 nm; and/or,

   The time of the ultraviolet irradiation is 5-15min.
5. The method for preparing a quantum dot light-emitting diode according to claim 1, wherein the step of preparing a quantum dot light-emitting layer containing quantum dots and a cross-linking agent on the surface of the hole functional layer comprises: adding a cross-linking agent and a cross-linking agent. The mixed solution of quantum dots is deposited on the surface of the hole functional layer and annealed.
6. The method for preparing a quantum dot light-emitting diode according to claim 5, wherein, in the mixed solution, the concentration of quantum dots is 10-50 mg/ml: and/or,

   In the mixed solution, the mass ratio of the crosslinking agent to the quantum dots is (0.5-5):100.
7. The method for preparing a quantum dot light-emitting diode according to claim 5, wherein the temperature of the annealing treatment is 50-250°C; and/or,

   The temperature of the annealing treatment is 10-30min.
8. The method for preparing a quantum dot light-emitting diode according to claim 5, wherein the mixed solution further contains a high molecular polymer, and the temperature of the annealing treatment is greater than or equal to the glass transition temperature of the high molecular polymer.
9. The method for preparing a quantum dot light-emitting diode according to claim 8, wherein the mass ratio of the high molecular polymer and the quantum dot is (0.5-10): 100; and/or,

   The glass transition temperature of the high molecular polymer is 50-150°C, and the temperature of the annealing treatment is 120-180°C.
10. The method for preparing a quantum dot light-emitting diode according to claim 8, wherein the high molecular polymer is selected from the group consisting of vinyl-based polymers, acryl-based polymers, amide-based polymers, phenyl-based polymers and At least one of carbonate-based polymers.
11. The method for preparing a quantum dot light-emitting diode according to claim 10, wherein the vinyl-based polymer is selected from the group consisting of polyvinyl alcohol, polyvinyl carbazole, polyvinyl acetate, polytetrafluoroethylene, polyvinylidene at least one of vinylidene fluoride and polyvinyl chloride; and/or,

    The acryl-based polymer is selected from at least one of polyacrylic acid, polymethyl methacrylate, poly(α-butyl cyanoacrylate), polyacrylamide and polyacrylonitrile; and/or,

    The amide polymer is selected from at least one of polydecylidene formamide and polyethylene sebacate; and/or,

    The phenyl-based polymer is selected from at least one of polyphenylene sulfide and polyethylene terephthalate; and/or,

    The carbonate-based polymer is selected from at least one of polycarbonate diol and brominated polycarbonate.
12. A quantum dot light-emitting diode, comprising an anode, a cathode and a quantum dot light-emitting layer located between the anode and the cathode, and a hole functional layer is arranged between the anode and the quantum dot light-emitting layer; it is characterized in that The material of the hole function layer is an organic material containing benzyl groups, the quantum dot light-emitting layer contains quantum dots and a cross-linking agent, and the quantum dot light-emitting layer and the hole function layer interface are cross-linked.
13. The quantum dot light-emitting diode of claim 12, wherein the cross-linking agent is selected from at least one of benzophenone and benzophenone derivatives.
14. The quantum dot light-emitting diode of claim 12, wherein the benzyl-containing organic material is selected from the group consisting of poly(9-vinylcarbazole), poly[(9,9-di-n-octylfluorenyl- 2,7-Diyl)-alt-(4,4′-(N-(4-n-butyl)phenyl)-diphenylamine)], poly[(9,9-di-n-octylfluorenyl-2 ,7-Phenyleneethylene)-alt-(2-methoxy-5-(2-ethylhexyloxy)-1,4diyl)], poly(9,9-dioctylfluorene- 2,7-diyl)-alt-(N,N'-diphenylbenzidine-N,N'-diyl), poly(9,9-di-n-octylfluorenyl-2,7-diyl) ), poly[(N,N'-(4-n-butylphenyl)-N,N'-diphenyl-1,4-phenylenediamine)-alt-(9,9-di-n-octylfluorene (2,7-diyl)], poly[9-(1-octylnonyl)-9H-carbazole], poly[2-methoxy-5-(2-ethylhexyloxy)-1, 4-phenylacetylene], poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylacetylene], poly[(9,9-dioctylfluorenyl-2,7 -diyl)-co-thiophene] and poly[(9,9-dioctylfluorenyl-2,7-diyl)-alt-(benzo[2,1,3]thiadiazole-4, 8-diyl)] at least one.
15. The quantum dot light-emitting diode according to claim 12, wherein the mass ratio of the crosslinking agent to the quantum dots is (0.5-5):100.
16. The quantum dot light-emitting diode according to claim 12, wherein the quantum dot light-emitting layer further contains a high molecular polymer, and the annealing temperature of the quantum dot light-emitting layer during annealing to form a film is greater than or equal to the high molecular polymer the glass transition temperature.
17. The quantum dot light-emitting diode according to claim 16, wherein the mass ratio of the high molecular polymer and the quantum dot is (0.5-10):100.
18. The quantum dot light-emitting diode of claim 16, wherein the high molecular polymer is selected from the group consisting of vinyl-based polymers, acryl-based polymers, amide-based polymers, phenyl-based polymers and carbonate-based polymers at least one of the polymers.
19. The quantum dot light-emitting diode of claim 18, wherein the vinyl-based polymer is selected from the group consisting of polyvinyl alcohol, polyvinylcarbazole, polyvinyl acetate, polytetrafluoroethylene, and polyvinylidene fluoride and at least one of polyvinyl chloride; and/or,

    The acryl-based polymer is selected from at least one of polyacrylic acid, polymethyl methacrylate, poly(α-butyl cyanoacrylate), polyacrylamide and polyacrylonitrile; and/or,

    The amide polymer is selected from at least one of polydecylidene formamide and polyethylene sebacate; and/or,

    The phenyl-based polymer is selected from at least one of polyphenylene sulfide and polyethylene terephthalate; and/or,

    The carbonate-based polymer is selected from at least one of polycarbonate diol and brominated polycarbonate.
20. The quantum dot light-emitting diode according to claim 12, wherein an electronic functional layer is disposed between the cathode and the quantum dot light-emitting layer.