Photocrosslinking hole transport small molecule material and application thereof
By introducing a photocrosslinked hole transport small molecule material with a large conjugated Π bond structure into quantum dots, the problems of reduced carrier transport characteristics and high-energy light source excitation during quantum dot patterning were solved, achieving efficient carrier injection balance and reduced energy consumption.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-22
- Publication Date
- 2026-06-19
Smart Images
Figure CN122233929A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of optoelectronic technology, specifically relating to a photocrosslinked hole transport small molecule material and its application, and more particularly, relating to an application of photolithographic quantum dot patterning based on the photocrosslinked hole transport small molecule material. Background Technology
[0002] The rise of virtual reality / augmented reality (VR / AR) technology is driving the rapid development of the display industry, leading to a continuous increase in demand for high-performance and high-resolution display devices. Quantum dot light-emitting diodes (QLEDs), with their advantages of low power consumption, narrow emission peaks, tunable wavelengths, and ease of integration, are one of the important technological routes for achieving high-resolution, high-brightness VR / AR displays and arrayed micro / nano light sources. Among these, photolithography can maturely fabricate micron- and submicron-scale patterns on substrates, making it a crucial technology for achieving ultra-high-resolution quantum dot (QD) displays. Currently, strategies for direct patterning of QDs based on non-destructive small-molecule photocrosslinking agents have been reported. This involves blending QDs with organic crosslinking agents containing photosensitive groups such as benzophenone, diazididine, or azide. During exposure, a photochemical reaction occurs, allowing aliphatic CH bonds to insert in situ into the surface ligands of the QD, thereby altering the solubility of the quantum dots in the solvent and achieving direct QD photolithographic patterning. However, most currently designed small-molecule photocrosslinking agents are insulating materials; their incorporation alters the carrier transport characteristics of the quantum dot film, thus reducing its electroluminescence performance. Meanwhile, these photocrosslinking agents often require shorter wavelength ultraviolet light excitation, increasing the risk of high-energy light sources affecting the intrinsic photoelectric properties of quantum dots.
[0003] In view of the above limitations, this invention provides a photocrosslinked hole-transporting small molecule material and its application, particularly relating to an application of photolithographic quantum dot patterning based on the photocrosslinked hole-transporting small molecule material. The invention involves doping the hole-transporting small molecule material with photocrosslinking groups into quantum dots. These photocrosslinking groups not only crosslink the -CH bonds in the quantum dot ligands, forming a more robust crosslinked network structure, but also significantly improve the hole injection capability in the QD by introducing hole transport units, thereby achieving efficient carrier injection balance. Furthermore, the hole transport units provide large conjugated π bonds, which enhance intramolecular electron delocalization, reduce excited-state energy requirements, and shift the crosslinking excitation light wavelength towards longer wavelengths. This avoids the use of high-energy light sources for excitation, reduces photoelectric damage to the quantum dots, and lowers energy consumption. Summary of the Invention
[0004] The purpose of this invention is to provide a photocrosslinked hole transport small molecule material and its application, so as to overcome the shortcomings of the prior art.
[0005] To achieve the above-mentioned objectives, the present invention adopts the following technical solution.
[0006] As a first aspect of the invention, this invention provides a photocrosslinked hole-transporting small molecule material with a large conjugated π-bond structure, which generates intramolecular electron delocalization and can undergo photopolymerization under long-wavelength ultraviolet light initiation. Preferably, the structure of the photocrosslinked hole-transporting small molecule material is any one of the following:
[0007] Wherein, R1 is a photocrosslinking group, and R2 = H or R2 = R1. In a preferred embodiment, R1 is selected from any of the following structural formulas:
[0008]
[0009] In some specific embodiments, the hole-transporting small molecule material is selected from any of the following structural formulas:
[0010]
[0011]
[0012]
[0013]
[0014] As one of the objectives of the invention, the present invention also provides a photocrosslinked light-emitting layer, comprising a photocrosslinked hole-transporting small molecule material and quantum dots as described above. Under the initiation of ultraviolet light, the hole-transporting small molecule material and quantum dots are mixed and spin-coated onto the surface of a substrate material. The hole-transporting small molecule material is crosslinked with the -CH bonds in the ligands of the quantum dots, and the light-emitting layer is formed after curing.
[0015] In a preferred embodiment, the quantum dot is any one of CdSe, CdS, CdZnSe, ZnSe, InP, or perovskite.
[0016] In a preferred embodiment, the mass percentage of the photocrosslinked hole transport small molecule material doped in the photocrosslinked light-emitting layer is 1-20%.
[0017] As a preferred embodiment, the photocrosslinking conditions are a 365nm wavelength UV curing lamp with an energy of 1–100 mJ / cm². -2 Exposure time: 1–600 seconds.
[0018] As one of the objectives of this invention, it also provides a method for patterning photolithographic quantum dots based on photocrosslinked hole transport small molecule materials, the specific steps of which include:
[0019] S1. Provides small molecule materials for optically cross-linked hole transport;
[0020] S2, provides a mixture of quantum dot-photocrosslinked hole transport small molecule materials;
[0021] Quantum dots and photocrosslinked hole transport small molecule materials are dissolved in an organic solvent and mixed evenly to obtain a quantum dot-photocrosslinked hole transport small molecule material mixture.
[0022] S3 provides quantum dot-photocrosslinked hole transport small molecule material thin films;
[0023] The quantum dot-photocrosslinked polymer mixture was spin-coated onto the surface of a substrate, annealed, and then masked with a photomask. Under ultraviolet light irradiation, photocrosslinking was performed, and after curing, a quantum dot-photocrosslinked hole transport small molecule material film was formed.
[0024] S4, Patterning
[0025] The quantum dot array is obtained by immersing the quantum dot-photocrosslinked hole transport small molecule material film in a developing solution.
[0026] In some specific embodiments, the organic solvent includes any one of toluene, xylene, chlorobenzene, or chloroform.
[0027] In a preferred embodiment, the developer is any one of toluene, octane, chlorobenzene, and xylene.
[0028] In a preferred embodiment, the annealing includes holding at 120–150°C for 5–20 minutes.
[0029] As one of the objectives of the invention, the present invention also provides another hole transport layer, which is prepared by the photolithographic quantum dot patterning method based on photocrosslinked hole transport small molecule materials as described above.
[0030] As one of the objectives of this invention, this invention also provides an application of the photocrosslinked hole transport small molecule material as described above, or the photolithographic quantum dot patterning method based on the photocrosslinked hole transport small molecule material as described above, in the preparation of organic light-emitting diodes and quantum dot light-emitting diodes.
[0031] As one of the objectives of this invention, this invention also provides a quantum dot electroluminescent device, comprising a quantum dot luminescent layer prepared by a photolithographic quantum dot patterning method based on photocrosslinked hole transport small molecule materials as described above.
[0032] Compared with the prior art, the present invention has at least the following beneficial effects:
[0033] 1. This invention introduces a photocrosslinked hole transport small molecule material into a quantum dot system and does it into the quantum dots. The photocrosslinked hole transport small molecule material is crosslinked with the -CH bonds in the ligands of the quantum dots. The crosslinking process can form a crosslinked network structure without the need to introduce a photoinitiator, but only through the initiation of ultraviolet light.
[0034] 2. In the technical solution of this invention, by introducing a photocrosslinked hole transport small molecule material with a large conjugated π bond structure, intramolecular electron delocalization can be generated, forming a hole transport unit under ultraviolet light initiation, thereby significantly improving the hole injection capability in QD and achieving efficient carrier injection balance.
[0035] 3. The hole transport unit formed by the photocrosslinking hole transport small molecule material in the technical solution of the present invention can also reduce the energy requirement of the excited state, shift the wavelength of the crosslinking excitation light to the long wavelength direction, avoid the use of high-energy light source for excitation, reduce photoelectric damage to quantum dots and reduce energy consumption. Attached Figure Description
[0036] Figures 1-8 The images show a comparison of fluorescence emission intensity before and after cleaning of the blend films formed by crosslinking quantum dots and photocrosslinked hole transport small molecule materials prepared in the embodiments of the present invention.
[0037] Figure 9 An optical microscope image of the photolithographic high-resolution quantum dot array prepared in Example 11 of the present invention. Detailed Implementation
[0038] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions in the embodiments of this application will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments.
[0039] This invention provides a photocrosslinked hole transport small molecule material with a large conjugated π bond structure, which can generate intramolecular electron delocalization and form hole transport units under ultraviolet light initiation. This reduces the energy requirement of the excited state, shifts the wavelength of the crosslinking excitation light to a longer wavelength direction, avoids the use of high-energy light sources for excitation, reduces photoelectric damage to quantum dots and reduces energy consumption; at the same time, it can also significantly improve the hole injection capability in QD, thereby achieving efficient carrier injection balance.
[0040] Unless otherwise specified, the intermediate raw materials (intermediates 1-4) used in the specific embodiments of the present invention are all purchased from Suzhou Opto-Display Technology Co., Ltd.
[0041] The technical solution of the present invention will be explained in more detail below with reference to several embodiments.
[0042] Example 1
[0043] This embodiment provides a method for preparing a photocrosslinked hole-transporting small molecule material, the specific steps of which include:
[0044] 4-(2-oxo-2-phenylacetyl)benzoic acid (0.648 g, 2.55 mmol), 4-pyrrolidinylpyridine (0.0378 g, 0.255 mmol), and N,N-dicycloethylcarbodiimide (0.528 g, 2.55 mmol) were mixed and added to a 50 mL three-necked flask. Then, dichloromethane (20 mL) and diethyl ether (5 mL) were added. Under nitrogen protection, the mixture was evacuated three times to ensure an oxygen-free atmosphere.
[0045] Under a nitrogen atmosphere, a dichloromethane solution (10 mL) of intermediate 1 (0.9 g, 1.2 mmol, Suzhou OPEC Display Technology Co., Ltd.) was added dropwise to the reaction system, and the mixture was stirred overnight at room temperature. The reaction was stopped, and the filtrate was washed three times each with deionized water and dilute acetic acid solution, and dried over anhydrous sodium sulfate. The solution was then concentrated by rotary evaporation, and the crude product was finally separated by silica gel column chromatography, yielding 10.58 g of compound 1 (40% yield).
[0046] Elemental analysis: (measured values) C, 91.8%; H, 5.57%; N, 2.58%.
[0047] The reaction principle is as follows:
[0048]
[0049] Example 2
[0050] This embodiment provides a method for preparing a photocrosslinked hole-transporting small molecule material, the specific steps of which include:
[0051] 4-azido-2,3,5,6-tetrafluorobenzoic acid (0.586 g, 2.55 mmol), 4-pyrrolidinylpyridine (0.0378 g, 0.255 mmol), and N,N-dicycloethylcarbodiimide (0.528 g, 2.55 mmol) were mixed and added to a 50 mL three-necked flask. Then, dichloromethane (20 mL) and diethyl ether (5 mL) were added. Under nitrogen protection, the mixture was evacuated three times to ensure an oxygen-free atmosphere.
[0052] Under a nitrogen atmosphere, a 10 mL solution of intermediate 1 (0.9 g, 1.2 mmol) in dichloromethane was added dropwise to the reaction system, and the mixture was stirred overnight at room temperature. The reaction was stopped, and the filtrate was washed three times each with deionized water and dilute acetic acid solution, and dried over anhydrous sodium sulfate. The solution was then concentrated by rotary evaporation, and the crude product was finally separated by silica gel column chromatography, yielding 30.5 g of compound 36% in yield. This compound was designated as compound 3.
[0053] Elemental analysis: (measured values) C, 72.42%; H, 3.80%; F, 13.67%; N, 10.08%.
[0054] The reaction principle is as follows:
[0055]
[0056] Example 3
[0057] This embodiment provides a method for preparing a photocrosslinked hole-transporting small molecule material, the specific steps of which include:
[0058] 4-(2-oxo-2-phenylacetyl)benzoic acid (0.648 g, 2.55 mmol), 4-pyrrolylpyridine (0.0378 g, 0.255 mmol), and N,N-dicycloethylcarbodiimide (0.528 g, 2.55 mmol) were mixed and added to a 50 mL three-necked flask. Then, dichloromethane (20 mL) and diethyl ether (5 mL) were added. The mixture was placed under nitrogen atmosphere and evacuated three times to ensure an oxygen-free atmosphere. Under nitrogen atmosphere, a dichloromethane solution (10 mL) of intermediate 2 (0.88 g, 1.2 mmol, Suzhou Oupuke Display Technology Co., Ltd.) was added dropwise to the reaction system, and the mixture was stirred overnight at room temperature. The reaction was stopped, and the filtrate was washed three times each with deionized water and dilute acetic acid solution, and dried over anhydrous sodium sulfate. The product was then concentrated by rotary evaporation, and the crude product was finally separated by silica gel column chromatography, yielding 50.61 g of compound 5, with a yield of 42%.
[0059] Elemental analysis (measured values): C, 92.18%; H, 5.22%; N, 2.59%.
[0060] The reaction principle is as follows:
[0061]
[0062] Example 4
[0063] This embodiment provides a method for preparing a photocrosslinked hole-transporting small molecule material, the specific steps of which include:
[0064] 4-azido-2,3,5,6-tetrafluorobenzoic acid (0.586 g, 2.55 mmol), 4-pyrrolylpyridine (0.0378 g, 0.255 mmol), and N,N-dicycloethylcarbodiimide (0.528 g, 2.55 mmol) were mixed and added to a 50 mL three-necked flask. Then, dichloromethane (20 mL) and diethyl ether (5 mL) were added. The mixture was placed under nitrogen atmosphere and evacuated three times to ensure an oxygen-free atmosphere. Under nitrogen atmosphere, a dichloromethane solution (10 mL) of intermediate 2 (0.88 g, 1.2 mmol) was added dropwise to the reaction system, and the mixture was stirred overnight at room temperature. The reaction was stopped, and the filtrate was washed three times each with deionized water and dilute acetic acid solution, and dried over anhydrous sodium sulfate. The product was then concentrated by rotary evaporation, and the crude product was finally separated by silica gel column chromatography, yielding 60.53 g of compound 6, with a yield of 38%.
[0065] Elemental analysis (measured values): C, 62.68%; H, 3.46%; F, 13.72%; N, 10.12%.
[0066] The reaction principle is as follows:
[0067]
[0068] Example 5
[0069] This embodiment provides a method for preparing a photocrosslinked hole-transporting small molecule material, the specific steps of which include:
[0070] 4-(2-oxo-2-phenylacetyl)benzoic acid (0.648 g, 2.55 mmol), 4-pyrrolylpyridine (0.0378 g, 0.255 mmol), and N,N-dicycloethylcarbodiimide (0.528 g, 2.55 mmol) were mixed and added to a 50 mL three-necked flask. Then, dichloromethane (20 mL) and diethyl ether (5 mL) were added. The mixture was placed under nitrogen atmosphere and evacuated three times to ensure an oxygen-free atmosphere. Under nitrogen atmosphere, a dichloromethane solution (10 mL) of intermediate 3 (0.65 g, 1.2 mmol, Suzhou Oupuke Display Technology Co., Ltd.) was added dropwise to the reaction system, and the mixture was stirred overnight at room temperature. The reaction was stopped, and the filtrate was washed three times each with deionized water and dilute acetic acid solution, and dried over anhydrous sodium sulfate. The product was then concentrated by rotary evaporation, and the crude product was finally separated by silica gel column chromatography, yielding 70.47 g of compound 7, with a yield of 39%.
[0071] Elemental analysis (measured values): C, 91.85%; H, 4.99%; N, 3.14%.
[0072] The reaction principle is as follows:
[0073]
[0074] Example 6
[0075] This embodiment provides a method for preparing a photocrosslinked hole-transporting small molecule material, the specific steps of which include:
[0076] 4-(2-oxo-2-phenylacetyl)benzoic acid (0.648 g, 2.55 mmol), 4-pyrrolylpyridine (0.0378 g, 0.255 mmol), and N,N-dicycloethylcarbodiimide (0.528 g, 2.55 mmol) were mixed and added to a 50 mL three-necked flask. Then, dichloromethane (20 mL) and diethyl ether (5 mL) were added. The mixture was placed under nitrogen atmosphere and evacuated three times to ensure an oxygen-free atmosphere. Under nitrogen atmosphere, (4... A 10 mL solution of 1.1 g (2.55 mmol) of 4-(bis(4-bromophenyl)amino)phenyl)methanol in dichloromethane was added dropwise to the reaction system, and the mixture was stirred overnight at room temperature. The reaction was stopped, and the filtrate was washed three times each with deionized water and dilute acetic acid, and dried over anhydrous sodium sulfate. The solution was then concentrated by rotary evaporation, and the crude product was finally separated by silica gel column chromatography, yielding intermediate a 50.87 g (51% yield); designated as compound 9.
[0077] Elemental analysis (measured values): C, 68.27%; H, 2.87%; F, 16.60%; N, 12.25%.
[0078] The reaction principle is as follows:
[0079]
[0080] Example 7
[0081] This embodiment provides a method for preparing a photocrosslinked hole-transporting small molecule material, the specific steps of which include:
[0082] 4-(2-oxo-2-phenylacetyl)benzoic acid (0.648 g, 2.55 mmol), 4-pyrrolidinylpyridine (0.0378 g, 0.255 mmol), and N,N-dicycloethylcarbodiimide (0.528 g, 2.55 mmol) were respectively mixed and added to a 50 mL three-necked flask, followed by the addition of dichloromethane (20 mL) and diethyl ether (5 mL) under nitrogen protection. The mixture was evacuated three times to ensure an oxygen-free atmosphere. Under a nitrogen atmosphere, a 10 mL solution of dichloromethane containing intermediate 4 (0.66 g, 0.8 mmol, Suzhou Oupuke Display Technology Co., Ltd.) was added dropwise to the reaction system, and the mixture was stirred overnight at room temperature. The reaction was stopped, and the filtrate was washed three times each with deionized water and dilute acetic acid solution, and dried over anhydrous sodium sulfate. The solution was then concentrated by rotary evaporation, and the crude product was finally separated by silica gel column chromatography, yielding compound 110.35 g (29% yield); this compound was designated as compound 11.
[0083] Elemental analysis: (measured values) C, 90.9%; H, 4.94%; N, 4.15%.
[0084] The reaction principle is as follows:
[0085]
[0086] Example 8
[0087] This embodiment provides a method for preparing a photocrosslinked hole-transporting small molecule material, the specific steps of which include:
[0088] 4-azido-2,3,5,6-tetrafluorobenzoic acid (0.586 g, 2.55 mmol), 4-pyrrolylpyridine (0.0378 g, 0.255 mmol), and N,N-dicycloethylcarbodiimide (0.528 g, 2.55 mmol) were mixed and added to a 50 mL three-necked flask. Then, dichloromethane (20 mL) and diethyl ether (5 mL) were added. The mixture was placed under nitrogen atmosphere and evacuated three times to ensure an oxygen-free atmosphere. Under nitrogen atmosphere, a dichloromethane solution (10 mL) of intermediate 4 (0.66 g, 0.8 mmol) was added dropwise to the reaction system, and the mixture was stirred overnight at room temperature. The reaction was stopped, and the filtrate was washed three times each with deionized water and dilute acetic acid solution, and dried over anhydrous sodium sulfate. The product was then concentrated by rotary evaporation, and the crude product was finally separated by silica gel column chromatography, yielding 130.26 g of compound 13, with a yield of 22%.
[0089] Elemental analysis: (measured values) C, 67.59%; H, 2.83%; F, 16.44%; N, 13.13%.
[0090] The reaction principle is as follows:
[0091]
[0092] Example 9
[0093] This embodiment first conducts a solvent resistance test on the cross-linked quantum dot film. The specific implementation is as follows:
[0094] The quartz substrate was subjected to O-plasma treatment for 3 minutes, followed by spin-coating of different toluene solutions prepared in Examples 1-8 above and mixed with red quantum dots, with a compound mass fraction of 5%. Then, the mixture was spin-coated onto the treated quartz substrate and annealed at 130°C for 10 minutes, followed by irradiation with a 365nm wavelength ultraviolet curing lamp for 30 seconds.
[0095] Fluorescence emission spectroscopy was used to study the changes in the cross-linked film before and after solvent washing, which can clearly determine whether the film has been eroded by the solvent. The fluorescence emission spectra were measured using an FLS1000 fluorescence spectrometer. Specifically, the fluorescence emission intensity of different samples was measured; all samples were washed with toluene solvent, and after the solvent dried, the fluorescence emission intensity of different samples was measured again. The results are as follows: Figures 1-8 As shown, after being cleaned with toluene, the emission spectrum of the quantum dot film after UV irradiation almost overlaps with that before cleaning, indicating that the cross-linked quantum dot film has excellent solvent resistance.
[0096] Example 10
[0097] Cross-linked quantum dots were patterned using photolithography and fabricated using photolithography technology, as detailed below.
[0098] (1) The quartz substrate was subjected to O-plasma treatment for 3 minutes. Taking compound 1 as an example, a toluene solution of compound material 1 mixed with red quantum dots was spin-coated, and the polymer mixture mass fraction was 5%.
[0099] (2) Then spin-coated onto the treated quartz plate and annealed at 60°C for 10 minutes. The quantum dot film is masked with a photomask and then irradiated with a 365nm wavelength ultraviolet curing lamp for 30 seconds.
[0100] (3) Using octane as the developing solution, the film was immersed for 20 seconds to obtain a high-resolution quantum dot lattice. The structure of the quantum dot lattice is as follows: Figure 9 As shown.
[0101] Example 11
[0102] This embodiment uses a red QLED as an example, and red quantum dot electroluminescent devices are fabricated by mixing the compounds provided in Examples 1-8 with quantum dots:
[0103] (1) Cleaning: Clean the surface of the ITO glass substrate with detergent, sonicate with ethanol and acetone to remove organic contaminants, rinse three times with ultrapure water, dry with nitrogen, and then treat with oxygen plasma (O-plasma) for 3 minutes to obtain a cleaned ITO glass substrate.
[0104] (2) Preparation of PEDOT:PSS layer: On the ITO glass substrate cleaned in step (1), PEDOT:PSS solution (1.4wt%) was spin-coated onto the treated ITO glass substrate (4000 rpm, 30s), and annealed at 130°C for 15 min in an atmospheric atmosphere, and then transferred to a nitrogen glove box (O2 < 1ppm, H2O < 1ppm).
[0105] (3) Preparation of HTL layer: spin-coat TFB chlorobenzene solution (8 mg / mL) on the HIL layer obtained in step (2) at a speed of 3000 rpm for 30 seconds, and anneal at 130℃ for 10 min.
[0106] (4) Preparation of the quantum dot luminescent layer: The compounds provided in Examples 1-8 were mixed with red quantum dots to prepare a 16 mg / mL toluene solution. Then, the mixture was spin-coated onto the HTL obtained in step (3), annealed at 60°C for 10 minutes, and then irradiated with a 365 nm wavelength UV curing lamp for 30 seconds. CdSe red quantum dots were selected as the quantum dots; the mass fraction of the compound in the luminescent layer was 5%, and the mass percentage of the quantum doped quantum dots was 5%.
[0107] (5) Preparation of ETL layer: Spin-coating Zn onto the QD obtained in step (4). 0.85 Mg 0.15 O nanocrystals (dispersed in ethanol, 25 mg / mL) -1 Spin coat at 3000 rpm for 30 seconds, then bake at 90°C for 15 minutes.
[0108] (6) The wafer is placed in a vacuum evaporation chamber and a 100nm aluminum electrode (Al) is vacuum evaporated to obtain a quantum dot electroluminescent device.
[0109] The structure of the fabricated QLED device is: ITO (~110nm) / PEDOT: PSS (~28nm) / HTL (25nm) / QDs (~20nm) / Zn 0.85 Mg 0.15 O (~50nm) / Al (~100nm).
[0110] The test data of the photocrosslinked QLED device are shown in Table 1.
[0111] Example 12
[0112] This embodiment takes red QLED as an example. Based on the compound 1 provided in Example 1, a red quantum dot electroluminescent device was fabricated by mixing it with quantum dots. The specific steps are the same as in Example 11. The only difference is that in step (4), this embodiment provides light-emitting layers with different quantum dot doping ratios, namely 1%, 3%, and 8%. The other steps are the same.
[0113] The results are shown in Table 2. As can be seen from the table, the maximum external quantum efficiency of the device is 18-20%, and the performance is best when the quantum dot doping amount is 5%.
[0114] Table 1 summarizes the performance of red QLED devices incorporating different compounds 1-8.
[0115] Devices Start-up voltage (V) Maximum external quantum efficiency (%) CIE(x, y) Pure QD 2.0 16.7 0.68，0.31 Compound 1: QD 1.8 20.1 0.68，0.31 Compound 2: QD 1.8 20.8 0.68，0.31 Compound 3: QD 1.8 21.9 0.68，0.31 Compound 4: QD 1.8 22.1 0.68，0.31 Compound 5: QD 2.4 24.3 0.68，0.31 Compound 6: QD 2.4 24.1 0.68，0.31 Compound 7: QD 2.2 22.8 0.68，0.31 Compound 8: QD 2.2 22.7 0.68，0.31
[0116] Note: The start-up voltage is 1 cd·m. -2 At that brightness.
[0117] Table 2 summarizes the performance of red QLED devices with different doping ratios of compound 1.
[0118] Devices Start-up voltage (V) Maximum external quantum efficiency (%) CIE(x, y) 1％ 1.8 18.0 0.68，0.31 3％ 1.8 18.6 0.68，0.31 5％ 1.8 20.1 0.68，0.31 8％ 1.8 19.2 0.68，0.31
[0119] Note: The start-up voltage is 1 cd·m. -2 At that brightness.
[0120] Furthermore, the HTL material in the technical solution of the present invention is not limited to the structural formulas of compounds 1, 3, 5, etc. already shown. Its photocrosslinking groups can also be selected from other structures that can crosslink between -CH bonds in the polymer to achieve the purpose of the present invention.
[0121] On the other hand, the quantum dots in this invention are not limited to the aforementioned blue quantum dots; other types such as red quantum dots, indium-based quantum dots, perovskites, etc., or any one of CdSe, CdS, CdZnSe, ZnSe, etc., can also be selected. It should be noted that the above description is merely a detailed illustration of the preferred embodiments of this invention. These embodiments are not intended to limit the scope of this application. Although those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features, any modifications, equivalent substitutions, or improvements made within the spirit and principles of this application should be included within the protection scope of this invention.
Claims
1. A photocrosslinked hole transport small molecule material, which has a large conjugated π bond structure in its structural formula, can generate intramolecular electron delocalization, and can undergo photopolymerization reaction initiated by long-wavelength ultraviolet light; The structure of the photocrosslinked hole-transporting small molecule material is any one of the following: in, R1 is a photocrosslinking group, and R2 = H or R2 = R1.
2. The hole-transporting small molecule material according to claim 1, characterized in that, R1 is selected from any of the following structural formulas:
3. The hole-transporting small molecule material according to claim 1 or 2, characterized in that, Choose any one of the following structural formulas:
4. A photocrosslinked light-emitting layer, comprising a photocrosslinked hole transport small molecule material as described in any one of claims 1-3, and quantum dots; under ultraviolet light initiation, the hole transport small molecule material and the quantum dots are mixed and spin-coated onto the surface of a substrate material, the hole transport small molecule material is crosslinked with the -CH bonds in the ligands of the quantum dots, and the photocrosslinked light-emitting layer is formed after curing.
5. The photocrosslinking light-emitting layer according to claim 4, characterized in that, The quantum dot is any one of CdSe, CdS, CdZnSe, ZnSe, InP, or perovskite.
6. The photocrosslinking light-emitting layer according to claim 4, characterized in that, The mass percentage of the photocrosslinked hole transport small molecule material doped in the photocrosslinked light-emitting layer is 1-20%.
7. The photocrosslinking light-emitting layer according to claim 4, characterized in that, The photocrosslinking conditions are a 365nm wavelength UV curing lamp with an energy of 1–100 mJ / cm². -2 Exposure time: 1–600 seconds.
8. A method for patterning photolithographic quantum dots based on photocrosslinked hole transport small molecule materials, characterized in that, The specific steps include: S1. Provides small molecule materials for optically cross-linked hole transport; S2, provides a mixture of quantum dot-photocrosslinked hole transport small molecule materials; Quantum dots and photocrosslinked hole transport small molecule materials are dissolved in an organic solvent and mixed evenly to obtain a quantum dot-photocrosslinked hole transport small molecule material mixture. S3 provides quantum dot-photocrosslinked hole transport small molecule material thin films; The quantum dot-photocrosslinked polymer mixture was spin-coated onto the surface of a substrate, annealed, and then masked with a photomask. Under ultraviolet light irradiation, photocrosslinking was performed, and after curing, a quantum dot-photocrosslinked hole transport small molecule material film was formed. S4, Patterning The quantum dot array is obtained by immersing the quantum dot-photocrosslinked hole transport small molecule material film in a developing solution.
9. The method for photolithographic high-resolution quantum dot patterning according to claim 8, characterized in that, The organic solvent includes any one of toluene, xylene, chlorobenzene, or chloroform; And / or, the developer is any one of toluene, octane, chlorobenzene, and xylene; And / or, the annealing includes holding at 120–150°C for 5–20 minutes.
10. A photolithographic quantum dot light-emitting layer, prepared by the photolithographic quantum dot patterning method based on photocrosslinked hole transport small molecule materials as described in any one of claims 8-9.
11. The application of a photocrosslinked hole-transporting small molecule material as described in any one of claims 1-3 or a photolithographic quantum dot patterning method based on a photocrosslinked hole-transporting small molecule material as described in any one of claims 8-9 in the fabrication of organic light-emitting diodes and quantum dot light-emitting diodes.
12. A quantum dot electroluminescent device, comprising a quantum dot emitting layer as described in claim 10, or comprising a quantum dot emitting layer prepared by a photolithographic quantum dot patterning method based on photocrosslinked hole transport small molecule materials as described in any one of claims 8-9.