Modified metal two-dimensional olefin material, preparation method and application thereof

Abstract

The application discloses a modified metal two-dimensional alkene material, a preparation method thereof, a hole injection composite material, a hole transmission composite material and a light emitting diode. The modified metal two-dimensional alkene material comprises a metal two-dimensional alkene material body, an unsaturated bond part of the metal two-dimensional alkene material body is added by a halogen atom, and a HOMO energy level of the modified metal two-dimensional alkene material is in a HOMO energy level interval of a hole injection material and / or a hole transmission material, or the HOMO energy level of the modified metal two-dimensional alkene material is close to the HOMO energy level of the hole injection material and / or the hole transmission material. The hole injection composite material and the hole transmission composite material both contain the modified metal two-dimensional alkene material. A hole injection layer material of the light emitting diode is the hole injection composite material, and / or a hole transmission layer material is the hole transmission composite material.

Description

Technical Field

[0001] This invention belongs to the field of optoelectronic technology, and particularly relates to a modified metal two-dimensional olefin material and its preparation method, hole injection composite material, hole transport composite material, and light-emitting diode. Background Technology

[0002] Light-emitting diodes (LEDs), such as quantum dot LEDs (QLEDs), have become a new generation of excellent display technologies due to their advantages such as high luminous efficiency, high color purity, narrow emission spectrum, and tunable emission wavelength. However, one of the main problems currently limiting the large-scale commercial application of LEDs such as QLEDs is their low device lifespan and poor stability. The most significant problem lies in the low efficiency of the hole injection layer and hole transport layer in the device structure, which cannot be balanced with the electron transport efficiency, resulting in low luminous efficiency of the LED.

[0003] The most significant advantage of existing hole injection and hole transport layer materials, such as organic polymers like PEDOT:PSS, TFB, and PVK, lies in their high hole mobility and strong processability. However, the excitons generated by organic materials are primarily Frenkel excitons. These excitons have electrons and holes bound within the volume cell, exhibiting strong Coulomb interactions, resulting in low exciton (hole) mobility and a radiation distance of no more than 100 nm. Therefore, the hole injection and hole transport layers can only provide a limited radiation range for efficient hole excitons, thus restricting the exciton radiation range of QLED devices and leading to lower luminous efficiency in light-emitting diodes like QLEDs. Summary of the Invention

[0004] One objective of this invention is to overcome the aforementioned deficiencies of the prior art and provide a modified metal two-dimensional olefin material and its preparation method, as well as a hole injection layer, a hole transport layer, and a light-emitting diode containing the modified metal two-dimensional olefin material, to solve the technical problem that existing organic hole transport materials have low hole migration rate and short radiation distance, resulting in low luminous efficiency of light-emitting diodes.

[0005] To achieve the aforementioned objectives, one aspect of the present invention provides a modified metal two-dimensional olefin material. The modified metal two-dimensional olefin material comprises a metal two-dimensional olefin material body, wherein the unsaturated bonds contained in the metal two-dimensional olefin material body are added by halogen atoms, and the HOMO energy level of the modified metal two-dimensional olefin material is within the HOMO energy level range of hole injection materials and / or hole transport materials, or the HOMO energy level of the modified metal two-dimensional olefin material is close to the HOMO energy level of hole injection materials and / or hole transport materials.

[0006] In another aspect, the present invention provides a method for preparing a modified metal two-dimensional olefin material. The method for preparing the modified metal two-dimensional olefin material includes the following steps:

[0007] In an inert atmosphere, a metal two-dimensional olefin material is subjected to an addition reaction with a halogen source to generate a modified metal two-dimensional olefin material.

[0008] In another aspect, the present invention provides a hole-injection composite material. The hole-injection composite material includes a hole-injection material, and further includes the modified metal two-dimensional olefin material of the present invention or the modified metal two-dimensional olefin material prepared by the method of the present invention.

[0009] Furthermore, this invention also provides a hole transport composite material. The hole transport composite material includes a hole transport composite material, and further includes the modified metal two-dimensional olefin material of this invention or the modified metal two-dimensional olefin material prepared by the method of this invention.

[0010] In another aspect, the present invention provides a light-emitting diode (LED). The LED includes a hole transport layer, at least one hole transport layer structure, wherein the hole injection layer is made of the hole injection composite material of the present invention; and / or

[0011] The material of the hole transport layer is the hole transport composite material of the present invention.

[0012] Compared with the prior art, the present invention has the following technical effects:

[0013] The unsaturated bonds in the modified metal two-dimensional olefin material of the present invention are added by halogen atoms, which causes the HOMO energy level of the modified metal two-dimensional olefin material to be down-regulated. This enables the modified metal two-dimensional olefin material to effectively increase the hole exciton radiation distance of hole injection materials and / or hole transport materials, and to increase the hole exciton migration rate.

[0014] The method for preparing modified metal two-dimensional olefin materials of the present invention can not only effectively control the degree of addition reaction, thereby down-regulating the HOMO energy level of the prepared modified metal two-dimensional olefin material, which can improve the radiation distance and migration rate of hole excitons of hole injection materials and / or hole transport materials, but also the preparation conditions are easy to control, resulting in stable performance of the prepared modified metal two-dimensional olefin material, and the preparation efficiency is high and the cost is low.

[0015] Because the hole injection composite material and hole transport composite material of the present invention contain the modified metal two-dimensional olefin material of the present invention, the hole injection composite material and the hole transport composite material can increase the radiation distance and migration rate of hole excitons. As a result, both the hole injection layer containing the hole injection composite material and the hole transport layer containing the hole transport composite material of the present invention can increase the radiation distance and migration rate of hole excitons, thereby increasing the number of hole excitons reaching the light-emitting layer and improving the luminous efficiency and intensity of the light-emitting layer.

[0016] The light-emitting diode of this invention contains a hole injection layer made of the hole injection composite material of this invention and / or a hole transport layer made of the hole transport composite material of this invention. Therefore, the hole injection layer and / or hole transport layer can significantly increase the hole exciton radiation distance and improve the hole exciton transport efficiency to reach the light-emitting layer, thereby exciting more light-emitting material within the same area of ​​the light-emitting layer to emit light, thus improving the luminous efficiency, EQE, and brightness of the light-emitting diode. Furthermore, the thickness of the light-emitting layer can be further increased to further improve the luminous efficiency, EQE, and brightness of the light-emitting diode. Attached Figure Description

[0017] 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.

[0018] Figure 1 This is a schematic diagram of a positive-type light-emitting diode structure provided in an embodiment of the present invention;

[0019] Figure 2 This is a schematic diagram of an inverted configuration light-emitting diode structure provided in an embodiment of the present invention. Detailed Implementation

[0020] To make the technical problems to be solved, the technical solutions, and the beneficial effects of the present invention clearer, the present invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0021] In this application, the term "and / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0022] In this application, "at least one" means one or more, and "more than one" means two or more. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or multiple items. For example, "at least one of a, b, or c", or "at least one of a, b, and c", can both mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be single or multiple.

[0023] It should be understood that in the various embodiments of this application, the order of the above processes does not imply the order of execution. Some or all steps may be executed in parallel or sequentially. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0024] The terminology used in the embodiments of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of this application. The singular forms "a" and "the" as used in the embodiments of this application and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise.

[0025] The weights of the relevant components mentioned in the embodiments of this application 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 application is within the scope disclosed in the embodiments of this application. Specifically, the mass in the embodiments of this application can be a well-known unit of mass in the chemical industry, such as μg, mg, g, or kg.

[0026] Because conventional metal two-dimensional olefin materials have very low band gaps, their HOMO energy levels differ significantly from those of hole injection and / or hole transport materials. Holes need to cross energy levels that are too deep to be transported. Therefore, conventional metal two-dimensional olefin materials cannot be directly used to improve the performance of hole materials. However, conventional metal two-dimensional olefin materials contain abundant unsaturated bonds, such as double bonds.

[0027] Based on the aforementioned characteristics of conventional two-dimensional metallo-propylene materials, this invention provides a modified two-dimensional metallo-propylene material. This modified two-dimensional metallo-propylene material comprises a metal two-dimensional propylene material body. In this invention, the unsaturated bonds in the metal two-dimensional propylene material body are added with halogen atoms. Because the unsaturated bonds are added with halogen atoms, the HOMO energy level of the modified metal two-dimensional propylene material resulting from the halogen atom addition is lowered. In this invention, by controlling and adjusting the degree of halogen atom addition to the unsaturated bonds, the HOMO energy level of the modified metal two-dimensional propylene material is made to be within the HOMO energy level range of the hole injection material and / or hole transport material, or the HOMO energy level of the modified metal two-dimensional propylene material is close to the HOMO energy level of the hole injection material and / or hole transport material. Because the HOMO energy level of the modified metal two-dimensional olefin material in this embodiment of the invention has this characteristic, after being doped with hole injection material and / or hole transport material, holes can freely migrate in the modified metal two-dimensional olefin material and hole injection material and / or hole transport material, which can effectively increase the hole injection material and / or hole transport material to the hole exciton radiation distance and increase the hole exciton migration rate.

[0028] In one embodiment, the HOMO energy level of the modified metal two-dimensional olefin material is -5.0 to -6.0 eV. By adjusting the HOMO energy level of the modified metal two-dimensional olefin material to this range, its doping effect on hole injection materials and / or hole transport materials can be further improved, enhancing the free migration of holes in the modified metal two-dimensional olefin material, hole injection materials, and / or hole transport materials, thereby increasing the hole exciton migration rate and the hole exciton radiation distance of the hole injection materials and / or hole transport materials.

[0029] The inventors further discovered in their research that controlling and optimizing the degree of halogen atom addition to the unsaturated bonds in the bulk of the metal two-dimensional olefin material can effectively control and adjust the HOMO energy level of the modified metal two-dimensional olefin material. In one embodiment, the molar percentage of unsaturated bonds in the bulk of the metal two-dimensional olefin material added by halogen atoms is 5% to 10%. By controlling and adjusting the molar ratio of unsaturated bonds added by halogen atoms, the HOMO energy level of the modified metal two-dimensional olefin material can be effectively adjusted to be within the HOMO energy level range of hole injection materials and / or hole transport materials, or the HOMO energy level of the modified metal two-dimensional olefin material is close to the HOMO energy level of hole injection materials and / or hole transport materials, preferably in the range of -5.0 to -6.0 eV, so as to exert its doping effect on hole injection materials and / or hole transport materials. Furthermore, the inventors discovered that if the addition ratio of halogen atoms decreases, such as below 5%, the deep energy level modification sites of the modified metal two-dimensional olefin material are lower, resulting in the above-mentioned doping effect of the modified metal two-dimensional olefin material on hole injection materials and / or hole transport materials being unsatisfactory; if the addition ratio is higher than 10%, the HOMO energy level of the modified metal two-dimensional olefin material is easily made too deep, leading to difficulty in injection and a decrease in the hole migration energy level.

[0030] In a specific embodiment, the metal two-dimensional olefin material body is composed of layered or / and sheet-like nanocrystals with a sheet diameter of 0.5–5 nm. The metal two-dimensional olefin material body includes at least one of tinene, leadene, and germanene. Thus, by selecting and optimizing the size and type of the metal two-dimensional olefin material body, the aforementioned doping effect of the modified metal two-dimensional olefin material on hole injection materials and / or hole transport materials can be improved.

[0031] Accordingly, embodiments of the present invention also provide a method for preparing the modified metal two-dimensional olefin material described above. The method for preparing the modified metal two-dimensional olefin material described above includes the following steps:

[0032] In an inert atmosphere, a metal two-dimensional olefin material is subjected to an addition reaction with a halogen source to generate a modified metal two-dimensional olefin material.

[0033] Thus, this method for preparing modified metal two-dimensional olefin materials not only effectively controls the degree of addition reaction, resulting in a downregulation of the HOMO energy level of the prepared modified metal two-dimensional olefin material, thereby increasing the exciton radiation distance and exciton migration rate of the hole injection and / or hole transport materials, achieving a doping effect on the hole injection and / or hole transport materials, but also ensures that the preparation conditions are easily controlled, resulting in stable performance of the prepared modified metal two-dimensional olefin material, and that the preparation is efficient and low-cost.

[0034] In one embodiment, the halogen source participating in the addition reaction is introduced into the reaction environment along with an inert gas, and the volume of the halogen source accounts for 2% to 5% of the total volume of the halogen source and the inert gas, with a gas introduction time of 10 to 60 minutes. By controlling and optimizing the contact method between the halogen source and the metal two-dimensional olefin material, the concentration of the halogen source in the addition reaction, and the addition time, the degree of addition of halogen atoms to the unsaturated bonds contained in the metal two-dimensional olefin material is controlled and optimized, thereby improving the doping effect of the generated modified metal two-dimensional olefin material on hole injection materials and / or hole transport materials as described above. Of course, the halogen source can also be directly placed in the reaction chamber with the metal two-dimensional olefin material first, and then the addition conditions are controlled to initiate the addition reaction.

[0035] In one embodiment, the addition reaction is carried out at 100–200°C for 10–60 minutes. Optimizing the addition reaction conditions improves the efficiency of the addition reaction and controls and optimizes the extent of the addition reaction.

[0036] In specific embodiments, the halogen source includes at least one of elemental halogens and halogen compounds. Elemental halogens can be chlorine, bromine, or iodine; halogen compounds include, but are not limited to, hydrogen halides, such as HCl. When the halogen source is liquid or solid, such as elemental bromine or iodine, it is preferable to first vaporize it and then introduce it into the addition reaction environment along with an inert gas. Alternatively, it can be directly placed in the reaction chamber with the two-dimensional metal olefin material, and then the addition conditions can be controlled to initiate the addition reaction.

[0037] Furthermore, metal two-dimensional olefin materials that undergo addition reactions with halogen sources, such as the metal two-dimensional olefin material contained in the modified metal two-dimensional olefin materials mentioned above, specifically include at least one of stanene, leadene, and germanene. While these metal two-dimensional olefin materials, such as stanene, leadene, and germanene, possess the intrinsic material property of high charge mobility, their extremely high charge mobility gives them exceptional hole transport capabilities, making them potential high-mobility hole transport materials. More importantly, as inorganic metal two-dimensional crystals, they exhibit the trajectory velocity and radiation range of Wannier excitons, with performance far exceeding that of Frenkel excitons in organic materials by hundreds or even thousands of times. However, these metal two-dimensional olefin materials have very low band gaps, and their HOMO energy levels differ significantly from those of hole-injection and / or hole-transporting materials. Therefore, through the above-mentioned addition reaction, their HOMO energy levels can be effectively lowered to reach the HOMO energy level range of hole-injection and / or hole-transporting materials, or the HOMO energy level of the modified metal two-dimensional olefin material can be close to that of hole-injection and / or hole-transporting materials, thereby fully leveraging its doping effect on hole-injection and / or hole-transporting materials.

[0038] Therefore, the above-mentioned method for preparing modified metal two-dimensional olefin materials can effectively control the degree of halogen atom addition and the HOMO energy level of the generated modified metal two-dimensional olefin materials, thereby improving their doping effect on hole injection materials and / or hole transport materials. Furthermore, the process conditions are controllable, resulting in stable performance of the prepared modified metal two-dimensional olefin materials and high preparation efficiency.

[0039] On the other hand, based on the modified metal two-dimensional olefin material and its preparation method described above, embodiments of the present invention also provide hole injection composite material and hole transport composite material.

[0040] The hole injection composite material of this invention includes an organic hole injection material and a modified metal two-dimensional olefin material. The organic hole injection material in the hole injection composite material can be a conventional organic hole injection material. For example, in a specific embodiment, the organic hole injection material includes, but is not limited to, PEDOT:PSS (poly(3,4-ethylenedioxythiophene):poly(styrenesulfonic acid)).

[0041] The modified two-dimensional metallene material contained in the hole injection composite material is the modified two-dimensional metallene material described in the embodiments of the present invention above. Therefore, the modified two-dimensional metallene material contained in the hole injection composite material can increase the exciton radiation distance and migration rate of the organic hole injection material, thereby enabling the hole injection layer containing the hole injection composite material of the embodiments of the present invention to increase the exciton radiation distance, improve the hole injection efficiency and migration rate, and increase the number of hole excitons reaching the light-emitting layer to improve the luminous efficiency and intensity of the light-emitting layer.

[0042] In one embodiment, the mass ratio of modified metal two-dimensional olefin material to organic hole injection material in the hole injection composite material is 5:95 to 20:80. By controlling and optimizing the ratio, the doping effect of the modified metal two-dimensional olefin material on the organic hole injection material can be improved, thereby increasing the exciton radiation distance and exciton migration rate of the organic hole injection material. Tests have shown that the hole injection composite material formed by doping the modified metal two-dimensional olefin material with organic hole injection material at a mass ratio of 5:95 to 20:80 can increase the exciton radiation distance of the hole injection composite material by 2 to 10 times. Further testing revealed that if the modified metal two-dimensional olefin material doping ratio is less than 5%, i.e., doped at a ratio of 5:95, the low proportion of modified two-dimensional olefin metal reduces the effectiveness of adding organic hole injection material to increase exciton radiation distance, thus reducing the exciton radiation distance of the hole injection composite material. If the modified metal two-dimensional olefin material doping ratio is higher than 20%, i.e., doped at a ratio of 20:80, the organic hole injection material content is low, which may affect the hole injection efficiency and migration rate of the hole injection composite material, reducing the hole injection effect.

[0043] Furthermore, the organic hole-injecting material and modified metal two-dimensional olefin material contained in the hole-injection composite material can be a mixture or set separately. When the two components are a mixture, for example, when formulating a film slurry (or ink), simply prepare the hole-injection composite material into a slurry according to the application requirements. When the two components are set separately, for example, when formulating a film slurry (or ink), then mix the two components evenly according to the application requirements.

[0044] Similarly, the hole transport composite material of this invention includes an organic hole transport material and a modified metal two-dimensional olefin material. The organic hole transport material in the hole transport composite material can be a conventional organic hole transport material. For example, in a specific embodiment, the organic hole transport material includes, but is not limited to, TEB.

[0045] The modified two-dimensional metallene material contained in the hole transport composite material is the modified two-dimensional metallene material described in the embodiments of the present invention above. Therefore, the modified two-dimensional metallene material contained in the hole transport composite material can increase the radiation distance of the organic hole transport material for hole excitons and increase the migration rate of hole excitons. As a result, the hole transport layer containing the hole transport composite material of the embodiments of the present invention can increase the radiation distance of hole excitons and increase the hole exciton transport efficiency and migration rate, and increase the number of hole excitons reaching the light-emitting layer to improve the luminous efficiency and intensity of the light-emitting layer.

[0046] In one embodiment, the mass ratio of modified metal two-dimensional olefin material to organic hole transport material in the hole transport composite material is 5:95 to 20:80. By controlling and optimizing the ratio, the doping effect of the modified metal two-dimensional olefin material on the organic hole transport material can be improved, thereby increasing the exciton radiation distance and exciton migration rate of the organic hole transport material. Tests have shown that hole transport composite materials formed by doping modified metal two-dimensional olefin material with organic hole transport material at a mass ratio of 5:95 to 20:80 can increase the exciton radiation distance of the hole transport composite material by 2 to 10 times. Further testing revealed that if the modified metal two-dimensional olefin material doping ratio is less than 5%, i.e., doped at a ratio of 5:95, the low proportion of modified two-dimensional olefin metal reduces the effectiveness of adding organic hole transport materials to increase exciton radiation distance, thus reducing the exciton radiation distance of the hole transport composite material. If the modified metal two-dimensional olefin material doping ratio is higher than 20%, i.e., doped at a ratio of 20:80, the content of organic hole transport materials is low, which may affect the hole migration rate of the hole transport composite material and reduce the hole transport effect.

[0047] Furthermore, the organic hole transport material and modified metal two-dimensional olefin material contained in the hole transport composite material can be a mixture or set separately. When the two components are a mixture, for example, when formulating a film slurry (or ink), simply prepare the hole transport composite material into a slurry according to the application requirements. When the two components are set separately, for example, when formulating a film slurry (or ink), then mix the two components evenly according to the application requirements.

[0048] Furthermore, based on the hole injection composite material and hole transport composite material described above, embodiments of the present invention also provide a light-emitting diode (LED). The LED includes a hole functional layer, such as a structure comprising at least one layer including a hole injection layer and a hole transport layer. Of course, the LED also contains other necessary layer structures, such as a light-emitting layer, an anode and a cathode, and an electronic functional layer. When the LED contains a hole injection layer, the material of the hole injection layer is the hole injection composite material described in the embodiments of the present invention above.

[0049] When the light-emitting diode contains a hole transport layer, the material of the hole transport layer is the hole transport composite material described in the above embodiment of the present invention.

[0050] When a light-emitting diode (LED) simultaneously contains a hole injection layer and a hole transport layer, the material of the hole injection layer is the hole injection composite material described in the embodiments of the present invention, or the material of the hole transport layer is the hole transport composite material described in the embodiments of the present invention, or both the hole injection layer and the hole transport layer are made of the same material. Thus, because the hole injection layer and / or hole transport layer in the LED of the present invention are made of the same material, the hole injection layer and / or hole transport layer can significantly increase the hole exciton radiation distance and improve the hole exciton transport efficiency to reach the light-emitting layer, thereby exciting more light-emitting material within the same area of ​​the light-emitting layer to emit light, thereby improving the luminous efficiency, EQE, and brightness of the LED. Furthermore, the thickness of the light-emitting layer can be further increased to further improve the luminous efficiency, EQE, and brightness of the LED.

[0051] Furthermore, depending on the light-emitting material contained in the light-emitting layer, the light-emitting diode in this embodiment of the invention can be a quantum dot light-emitting diode (QLED) or an organic light-emitting diode (OLED). Depending on the structural configuration of the light-emitting diode, the light-emitting diode in this embodiment of the invention can be a positive-type light-emitting diode or an inverted-type light-emitting diode.

[0052] In one embodiment, the structure of a positive light-emitting diode is as follows: Figure 1As shown, it includes a stacked structure of an anode 10 and a cathode 50 disposed opposite to each other. The anode 10 can be stacked and bonded on a substrate 01, and a light-emitting functional layer is stacked and bonded between the anode 10 and the cathode 50. The light-emitting functional layer includes a light-emitting layer 30, a hole transport layer 20, and an electron transport layer 40. From the anode 10 to the cathode 50, the hole transport layer 20, the light-emitting layer 30, and the electron transport layer 40 are stacked sequentially. Furthermore, a hole injection layer can also be disposed between the hole transport layer 20 and the anode 10. Figure 1 (Not shown), an electron injection layer can also be provided between the electron transport layer 40 and the cathode 50. Figure 1 (Not displayed).

[0053] So, in the preparation of such Figure 1 When a positive light-emitting diode is shown, a hole transport layer 20, a light-emitting layer 30, an electron transport layer 40 (or a hole injection layer is further formed), and a cathode 50 are sequentially formed on the surface of the anode 10.

[0054] In another embodiment, the structure of the inversion-type light-emitting diode is as follows: Figure 2 As shown, it includes a stacked structure of an anode 10 and a cathode 50 disposed opposite to each other. The cathode 50 can be stacked and bonded on a substrate 01. A light-emitting functional layer is stacked and bonded between the anode 10 and the cathode 50. The light-emitting functional layer includes a light-emitting layer 30, a hole transport layer 20, and an electron transport layer 40. From the anode 10 to the cathode 50, the hole transport layer 20, the light-emitting layer 30, and the electron transport layer 40 are stacked sequentially. Furthermore, a hole injection layer can also be disposed between the hole transport layer 20 and the anode 10. Figure 2 (Not shown), an electron injection layer can also be provided between the electron transport layer 40 and the cathode 50. Figure 2 (Not shown). This inverted structure LED is the preferred structure of this invention.

[0055] So, in the preparation of such Figure 2 In the case of the inverted light-emitting diode shown, the cathode 50 is formed sequentially with an electron transport layer 40, a light-emitting layer 30, a hole transport layer 20, and an anode 10 (if there is a hole injection layer, a hole injection layer is formed first) on the surface of the cathode 50.

[0056] In a further embodiment, substrate 01 includes rigid substrates, flexible substrates, etc.

[0057] The anode 10 is made of conductive glass substrates such as ITO, FTO, or ZTO. To form a high-quality charge material film, the anode 10 requires pretreatment. This can be done by following these basic steps: cleaning the substrate 01 containing the anode 10 with a cleaning agent to initially remove surface contaminants; then, sequentially ultrasonically cleaning it for 20 minutes each in deionized water, acetone, anhydrous ethanol, and deionized water to remove surface impurities; finally, drying it with high-purity nitrogen to obtain the anode 10.

[0058] The material of the hole injection layer is the hole injection composite material described in the above embodiment of the present invention. Of course, it can also be a conventional organic hole injection material, which can be prepared by methods not limited to drop coating, spin coating, immersion, coating, printing, vapor deposition, etc.

[0059] The hole transport layer 20 is made of the hole transport composite material described in the above embodiment of the invention. Of course, it can also be a conventional organic hole transport material. However, the material of at least one of the hole transport layer 20 and the hole injection layer is the hole composite material (hole injection composite material or hole transport composite material) described above. The hole transport layer 20 can be prepared by methods not limited to drop coating, spin coating, immersion, coating, printing, evaporation, etc.

[0060] The luminescent layer 30 can be a quantum dot or an organic fluorescent luminescent material. When it is a quantum dot, the quantum dot is an oil-based quantum dot, and its surface is attached with ligands that are readily soluble in solvents with low polarity. The ligands of the quantum dot include at least one of acid ligands, thiol ligands, amine ligands, (oxy)phosphine ligands, phospholipids, lecithin, polyvinylpyridine, etc. As a specific embodiment, the acid ligand is at least one of decacarboxylic acid, undecenoic acid, tetradecanoic acid, oleic acid, and stearic acid; the thiol ligand is at least one of octaalkylthiol, dodecylthiol, and octadecylthiol; the amine ligand includes at least one of oleylamine, octadecylamine, and octadecylamine; and the (oxy)phosphine ligand is at least one of trioctylphosphine and trioctylphosphine oxide. The luminescent quantum dots are oil-soluble quantum dots, including binary, ternary, and quaternary phase quantum dots; among them, binary phase quantum dots include CdS, CdSe, CdTe, InP, AgS, PbS, PbSe, HgS, etc., but are not limited to these; ternary phase quantum dots include Zn X Cd 1-X S, Cu X In 1-X S, Zn X Cd 1-X Se、Zn X Se 1-X S, Zn X Cd 1- X Te, PbSe X S 1-XAnd not limited to this, quaternary quantum dots include Zn X Cd 1-X S / ZnSe, Cu X In 1-X S / ZnS, Zn X Cd 1-X Se / ZnS, CuInSeS, Zn X Cd 1-X Te / ZnS, PbSe X S 1-X / ZnS, etc., are not limited to these. In quantum dot inks, the concentration of quantum dots is 1-200 mg / mL, preferably 20-50 mg / mL. Within this concentration range, the solution processing performance and dispersibility of quantum dots are good. The light-emitting layer 30 can be prepared by the following method: a substrate with a hole transport layer 20 (positive light-emitting diode) or electron transport layer 40 spin-coated is placed on a spin coater, and a precursor solution of a certain concentration of light-emitting layer 30 is spin-coated into a film. The thickness of the light-emitting layer 30, approximately 5-100 nm, is controlled by adjusting the concentration of the solution, the spin-coating speed (preferably between 2000-6000 rpm), and the spin-coating time. Then, the film is annealed at a temperature of 200℃-250℃ (e.g., 200℃). This step can be annealed in an inert atmosphere; the specific annealing temperature and atmosphere are selected according to actual needs.

[0061] The electron transport material of the electron transport layer 40 can be made of conventional electron transport materials in the art, including but not limited to one or more of zinc oxide (ZnO), titanium oxide (TiO2), zirconium oxide (ZrO2), CsF, LiF, CsCO3, and Alq3, as well as their dopants. Preparation of the electron transport layer: A substrate with a spin-coated light-emitting layer 30 (positive light-emitting diode), cathode 50, or electron injection layer (inverting light-emitting diode) is placed in a vacuum evaporation chamber, and an electron transport layer 400 of approximately 80 nm thickness is deposited at a evaporation rate of approximately 0.01–0.5 nm / s, followed by annealing at an appropriate temperature.

[0062] The cathode 50 is made of Al, Ag, Au, Cu, Mo, or alloys thereof. In one embodiment, it can be formed by vapor deposition, such as by thermally vapor-depositing a 15-30 nm layer of metallic silver or aluminum in a vapor deposition chamber using a mask as the cathode 50, or by using nano-Ag wires or Cu wires, which have low resistance to allow for smooth carrier injection.

[0063] To enable those skilled in the art to clearly understand the above-described implementation details and operations of the present invention, and to demonstrate the significant advancements in the performance of the modified metal two-dimensional olefin material, hole injection composite material, hole transport composite material, and light-emitting diode and their preparation methods in the embodiments of the present invention, the above technical solutions are illustrated below through multiple embodiments.

[0064] 1. Examples of Modified Metal Two-Dimensional olefin Materials and Their Preparation Methods

[0065] Example 11

[0066] This embodiment provides a modified two-dimensional tinene metal material and its preparation method. The preparation method of the modified two-dimensional tinene metal material includes the following steps:

[0067] Two-dimensional stanene metal nanosheets with a diameter of 0.5–2 nm were heated to 120 °C in an argon atmosphere, followed by the introduction of 5% HCl-argon combined gas and holding for 30 minutes to obtain 5% mol / L stanene chloride metal nanosheets with Cl atom addition.

[0068] Example 12

[0069] This embodiment provides a modified two-dimensional leadene metal material and its preparation method. The preparation method of the modified two-dimensional leadene metal material includes the following steps:

[0070] Two-dimensional leadene metal nanosheets with a diameter of 0.5–2 nm were heated to 120 °C in an argon atmosphere, followed by the introduction of 3% Br2-argon combined gas and holding for 30 minutes to obtain two-dimensional leadene metal nanosheets with 6% mol% Br atom addition.

[0071] Example 13

[0072] This embodiment provides a modified two-dimensional tinene metal material and its preparation method. The preparation method of the modified two-dimensional tinene metal material includes the following steps:

[0073] Two-dimensional stanene metal nanosheets with a diameter of 0.5–2 nm were heated to 120 °C in an argon atmosphere, followed by the introduction of a 10% HCl-argon gas mixture and holding for 30 minutes to obtain stanene metal nanosheets with 10% mol% Cl atom addition.

[0074] 2. Examples of Light Emitting Diodes and Their Fabrication Methods

[0075] In the following embodiments, the thickness of the ITO substrate is 30 nm, the thickness of the hole injection layer is 60 nm, the thickness of the hole transport layer is 60 nm, the thickness of the ZnO electron transport layer is 80 nm, and the thickness of the Ag cathode is 80 nm.

[0076] Example 21

[0077] This embodiment provides a QLED light-emitting diode and its fabrication method. The QLED light-emitting diode is a positive quantum dot light-emitting diode, comprising an ITO substrate / modified hole injection layer / TFB hole transport layer / (CdSeS / ZnS) green quantum dot light-emitting layer / ZnO electron transport layer / Ag cathode. The " / " indicates the layered structure connection relationship. The modified hole injection layer is a mixture of stannous chloride metal two-dimensional nanosheets and PEDOT:PSS provided in Example 11 at a mass ratio of 1:20, and the green quantum dot light-emitting layer has a thickness of 20 nm.

[0078] The QLED fabrication method in this embodiment includes the following steps:

[0079] S1: Provides ITO substrate (anode);

[0080] The entire ITO conductive glass is cleaned with a cleaning agent to initially remove the stains on the surface. Then, it is ultrasonically cleaned for 20 minutes each in deionized water, acetone, anhydrous ethanol, and deionized water to remove impurities on the surface. Finally, it is dried with high-purity nitrogen to obtain the ITO substrate.

[0081] S2: Under an argon atmosphere, the stannous chloride metal two-dimensional nanosheets prepared in Example 11 were added to a PEDOT:PSS solution at a mass ratio of stannous chloride metal two-dimensional nanosheets:PEDOT:PSS = 1:20. The mixture was stirred at room temperature for 30 minutes to obtain a stannous chloride metal-modified hole injection composite material. The hole injection composite material was then spin-coated into a film to form a modified hole injection layer.

[0082] S3: A TFB hole transport layer, a CdSeS / ZnS green quantum dot layer, and a ZnO electron transport layer are sequentially formed on the surface of the modified hole injection layer;

[0083] S4: Deposit Ag electrodes on the surface of the ZnO electron transport layer.

[0084] Example 22

[0085] This embodiment provides a QLED light-emitting diode and its fabrication method. The structure and fabrication method of the QLED light-emitting diode are the same as those of the QLED light-emitting diode in Embodiment 21, except that the thickness of the green quantum dot light-emitting layer is 80 nm.

[0086] Example 23

[0087] This embodiment provides a QLED light-emitting diode and its fabrication method. The structure and fabrication method of the QLED light-emitting diode are the same as those of the QLED light-emitting diode in Embodiment 21. The difference is that, based on the QLED light-emitting diode in Embodiment 21, the hole transport layer material is also a hole transport composite material prepared in Embodiment 11, in which stannous chloride metal two-dimensional nanosheets are doped and modified with TFB at a mass ratio of stannous chloride metal two-dimensional nanosheets:TFB = 1:20.

[0088] The hole transport composite material is prepared as follows: Under an argon atmosphere, the stannous chloride metal two-dimensional nanosheets prepared in Example 11 are added to a TFB solution at a mass ratio of stannous chloride metal two-dimensional nanosheets: TFB = 1:20. The mixture is stirred at room temperature for 30 minutes to obtain the stannous chloride metal-modified hole transport composite material. The hole transport composite material is then spin-coated into a film to form a modified hole transport layer.

[0089] Example 24

[0090] This embodiment provides a QLED light-emitting diode and its fabrication method. The QLED light-emitting diode is a positive quantum dot light-emitting diode, comprising an ITO substrate / modified hole injection layer / TFB hole transport layer / (CdSeS / ZnS) green quantum dot light-emitting layer / ZnO electron transport layer / Ag cathode. The " / " indicates the layered structure connection relationship. The modified hole injection layer is a mixture of lead bromide metal two-dimensional nanosheets and PEDOT:PSS provided in Example 12 at a mass ratio of 1:25, and the green quantum dot light-emitting layer has a thickness of 20 nm.

[0091] The QLED fabrication method in this embodiment includes the following steps:

[0092] S1: Provide an ITO substrate (anode); clean the entire ITO conductive glass with a cleaning agent to initially remove the stains on the surface, and then ultrasonically clean it for 20 minutes in deionized water, acetone, anhydrous ethanol and deionized water respectively to remove the impurities on the surface. Finally, blow it dry with high-purity nitrogen to obtain the ITO substrate.

[0093] S2: Under an argon atmosphere, the lead bromide metal two-dimensional nanosheets prepared in Example 12 were added to a PEDOT:PSS solution at a mass ratio of lead bromide metal two-dimensional nanosheets:PEDOT:PSS = 1:25. The mixture was stirred at room temperature for 30 minutes to obtain a hole injection composite material modified with lead bromide metal two-dimensional nanosheets. The hole injection composite material was then spin-coated into a film to form a modified hole injection layer.

[0094] S3: A TFB hole transport layer, a CdSeS / ZnS green quantum dot layer, and a ZnO electron transport layer are sequentially formed on the surface of the modified hole injection layer;

[0095] S4: Deposit Ag electrodes on the surface of the ZnO electron transport layer.

[0096] Example 25

[0097] This embodiment provides a QLED light-emitting diode and its fabrication method. The QLED light-emitting diode is a positive quantum dot light-emitting diode, comprising an ITO substrate / modified hole injection layer / TFB hole transport layer / (CdSeS / ZnS) green quantum dot light-emitting layer / ZnO electron transport layer / Ag cathode. The " / " indicates the layered structure connection relationship. The modified hole injection layer is a mixture of stannous chloride metal two-dimensional nanosheets and PEDOT:PSS provided in Example 13 at a mass ratio of 1:10, and the thickness of the green quantum dot light-emitting layer is 20 nm.

[0098] The QLED fabrication method in this embodiment includes the following steps:

[0099] S1: Provide an ITO substrate (anode); clean the entire ITO conductive glass with a cleaning agent to initially remove the stains on the surface, and then ultrasonically clean it for 20 minutes in deionized water, acetone, anhydrous ethanol and deionized water respectively to remove the impurities on the surface. Finally, blow it dry with high-purity nitrogen to obtain the ITO substrate.

[0100] S2: Under an argon atmosphere, the stannous chloride metal two-dimensional nanosheets prepared in Example 13 were added to a PEDOT:PSS solution at a mass ratio of stannous chloride metal two-dimensional nanosheets:PEDOT:PSS = 1:10. The mixture was stirred at room temperature for 30 minutes to obtain a hole injection composite material modified with stannous chloride metal two-dimensional nanosheets. The hole injection composite material was then spin-coated into a film to form a modified hole injection layer.

[0101] S3: A TFB hole transport layer, a CdSeS / ZnS green quantum dot layer (20 nm thick) and a ZnO electron transport layer are sequentially formed on the surface of the modified hole injection layer;

[0102] S4: Deposit Ag electrodes on the surface of the ZnO electron transport layer.

[0103] Example 26

[0104] This embodiment provides a QLED light-emitting diode and its fabrication method. The structure and fabrication method of the QLED light-emitting diode are the same as those of the QLED light-emitting diode in Example 23, except that its hole injection layer material is PEDOT:PSS (that is, without the addition of the stannous chloride metal two-dimensional nanosheets prepared in Example 11), and the hole transport layer material is the same as that of the hole transport layer in Example 23. The hole transport composite material is a doped and modified TFB with the stannous chloride metal two-dimensional nanosheets prepared in Example 11 at a mass ratio of stannous chloride metal two-dimensional nanosheets:TFB = 1:20.

[0105] Comparative Example 1

[0106] This comparative example provides a QLED light-emitting diode and its fabrication method. The structure of the QLED light-emitting diode in this comparative example is the same as that in Example 21. The difference is that the hole injection layer material in the QLED light-emitting diode is PEDOT:PSS without stannous chloride metal two-dimensional nanosheets, that is, the hole injection layer material is the existing PEDOT:PSS.

[0107] Comparative Example 2

[0108] This comparative example provides a QLED light-emitting diode and its fabrication method. The structure of the QLED light-emitting diode in this comparative example is the same as that in Example 21. The difference is that the hole injection layer of the QLED light-emitting diode is made of PEDOT:PSS, a metal two-dimensional nanosheet without stannous chloride, and the thickness of the green quantum dot light-emitting layer is adjusted to 80 nm.

[0109] Quantum dot light-emitting diode photoelectric performance testing

[0110] The hole mobility and EQE of the QLED devices prepared in Examples 21 to 25 and Comparative Examples 1 to 2 were tested respectively. The specific methods are as follows:

[0111] First, the current density (J)-voltage (V) of the QLED devices prepared in Examples 21 to 25 and Comparative Examples 1 to 2 were tested respectively, and the curve relationship was plotted. Then, the space charge confinement current (SCLC) region in the relationship was fitted, and the hole mobility was calculated according to the well-known Child's law formula: J = (9 / 8)ε r ε0μ e V 2 / d 3 Where J represents current density, in mA / cm². -2 ;ε r ε₀ represents the relative permittivity, and μ represents the vacuum permittivity. e Hole mobility is expressed in cm. 2 V- 1 s -1 V represents the driving voltage, in volts (V); d represents the film thickness, in meters (m). The test results are shown in Table 1 below:

[0112] Table 1

[0113]

[0114] As can be seen from the test results in Table 1 above, the hole mobility of the QLED devices prepared in Examples 21, 24 and 25 of this invention is significantly higher than that of Comparative Example 1 without modified materials, and the EQE of the QLED devices is also significantly higher.

[0115] Comparing Examples 21 and 22, it can be seen that even when the thickness of the quantum dot luminescent layer is increased by 4 times, it can still be excited by excitons and emit light, and the luminescence efficiency can also be improved. This proves that the modified metal two-dimensional olefin material provided in the embodiments of the present invention, such as the metal modified material of two-dimensional tin chloride, can improve the radiation distance of hole excitons.

[0116] Comparing Examples 21, 22, and Comparative Example 2, it can be seen that in Comparative Example 2, the hole mobility and EQE of the hole injection layer and hole transport layer without the modified metal two-dimensional olefin material of the present invention decreased significantly after the thickness of the quantum dot light-emitting layer increased by 4 times. This proves that the exciton radiation distance is insufficient to support a QLED with a thickness of 80nm. It further proves that the modified metal two-dimensional olefin material provided by the present invention can improve the hole exciton radiation distance of organic hole transport materials and organic hole injection materials.

[0117] Compared with Examples 21, 22, 24, and 25, Example 23 shows a significantly higher hole mobility, while the EQE of Examples 21, 22, 24, and 25 are very close to that of Example 23. This demonstrates that the modified metal two-dimensional olefin material provided by the embodiments of the present invention, used in both single-layer materials (hole injection layer) and double-layer materials (hole injection layer plus hole transport layer), can increase the exciton radiation distance of organic hole transport materials and organic hole injection materials, and can also improve hole injection and transport efficiency and rate (double-layer modification is relatively superior), thereby improving the luminous efficiency and luminous intensity of the diode.

[0118] Comparing Examples 23 and 26 with Comparative Example 1, it is evident that the hole mobility of the QLED devices in Examples 23 and 26 is significantly higher than that of the QLED device in Comparative Example 1. Therefore, doping the hole transport layer with the modified two-dimensional metallene material of this invention can significantly improve the hole mobility of the hole transport layer and the EQE of the device. Comparing Examples 23 and 26, when both the hole injection layer and the hole transport layer are doped with the modified two-dimensional metallene material of this invention, the hole mobility and EQE of the corresponding devices are even better.

[0119] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A modified metal two-dimensional olefin material, comprising a metal two-dimensional olefin material body, wherein the unsaturated bond portion of the metal two-dimensional olefin material body is added by halogen atoms, and the HOMO energy level of the modified metal two-dimensional olefin material is -5.0 to -6.0 eV; The metal two-dimensional olefin material body includes at least one of tinene, leadene, and germanene; The molar percentage of unsaturated bonds in the bulk metal two-dimensional olefin material that are added by halogen atoms is 5-10%.

2. The modified metal two-dimensional olefin material as described in claim 1, characterized in that: The metal two-dimensional olefin material body has a sheet diameter of 0.5 to 5 nm and consists of layered or / and sheet-like nanocrystals.

3. The method for preparing the modified metal two-dimensional olefin material according to any one of claims 1-2, comprising the following steps: In an inert atmosphere, a metal two-dimensional olefin material is subjected to an addition reaction with a halogen source to generate a modified metal two-dimensional olefin material.

4. The preparation method according to claim 3, characterized in that: The halogen source includes at least one of elemental halogens and halogen compounds; and / or The halogen source is introduced into the environment of the addition reaction along with an inert gas, and the volume concentration of the halogen source in the total volume of the halogen source and the inert gas is 2% to 5%, with a gas introduction time of 10 to 60 minutes; and / or The addition reaction is carried out at a temperature of 100–200 °C.

5. A cavity injection composite material, characterized in that: It includes organic hole injection materials, and also includes the modified metal two-dimensional olefin material according to any one of claims 1-2 or the modified metal two-dimensional olefin material prepared by the preparation method according to any one of claims 3-4.

6. The cavity injection composite material as described in claim 5, characterized in that: The mass ratio of the modified metal two-dimensional olefin material to the organic hole injection material is 5:95 to 20:

80.

7. A hole transport composite material, comprising an organic hole transport material, and further comprising the modified metal two-dimensional olefin material according to any one of claims 1-2 or the modified metal two-dimensional olefin material prepared by the preparation method according to any one of claims 3-4.

8. The hole transport composite material as described in claim 7, characterized in that: The mass ratio of the modified metal two-dimensional olefin material to the organic hole transport material is 5:95 to 20:

80.

9. A light-emitting diode, comprising at least one structure of a hole injection layer and a hole transport layer, characterized in that: The material of the hole injection layer is the hole injection composite material according to any one of claims 5-6; and / or The material of the hole transport layer is the hole transport composite material as described in any one of claims 7-8.

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