OLED (Organic Light Emitting Diode) organic small molecule luminescent material with self-repairing function

Abstract

The invention belongs to the field of OLED (organic light emitting diode) luminescent materials, and particularly relates to an OLED organic small molecular luminescent material with a self-repairing function, which is composed of 90-99.9% by mass of host luminescent molecules A and 0.1-10% by mass of dynamic covalent cross-linking agent B. The mass ratio of the host luminescent molecules A is 90-99.9%, the mass ratio of the dynamic covalent cross-linking agent B is 0.1-10%, and the mass ratio of the host luminescent molecules A to the dynamic covalent cross-linking agent B is 0.1-10%. The structural general formula of the main body light-emitting molecule A is Ar1-L-Ar2. According to the OLED organic small-molecular luminescent material with the self-repairing function, a reversible dynamic cross-linked network is constructed through reasonable proportioning of the host luminescent molecules A and the dynamic covalent cross-linking agent B (the proportion of the host molecules is 90%-99.9%, and the proportion of the cross-linking agent is 0.1%-10%). When the light-emitting layer has defects due to aging, thermal stress or mechanical damage, external stimulation (heating at the temperature of 50 DEG C to 150 DEG C or ultraviolet irradiation at the wavelength of 300 nm to 400 nm) can activate fracture-recombination of dynamic covalent bonds such as disulfide bonds and borate bonds, molecular chains are promoted to be crosslinked again, and the microstructure of the light-emitting layer is repaired.

Description

Technical Field

[0001] The present invention relates to the technical field of OLED luminescent materials, and in particular to an OLED organic small molecule luminescent material with a self-repairing function. Background Art

[0002] At present, organic light-emitting diode (OLED) technology has shown broad application prospects in the fields of display and lighting due to its advantages of high contrast, flexibility and bendability, and low power consumption. However, existing OLED organic small molecule luminescent materials are easily affected by factors such as electric fields, thermal stress, and mechanical deformation during long-term operation, resulting in molecular structure damage, interface defects or film cracking in the luminescent layer material, which in turn causes a decrease in electroluminescent efficiency, brightness attenuation, and even device failure. Traditional solutions mostly rely on packaging technology or structural optimization, but cannot repair internal damage from the essence of the material. For example, under continuous electrical drive, conventional luminescent materials will cause molecular chain breakage or aggregation, resulting in attenuation of luminous efficiency, while mechanical stress such as bending and folding in flexible devices can easily cause irreversible cracks in the luminescent layer, significantly shortening the life of the device.

[0003] While dynamic covalent bonds (such as disulfide bonds and borate bonds) have been explored in the field of self-healing materials, their application in OLED luminescent materials faces key bottlenecks: First, the incompatibility between the crosslinker and the host luminescent molecule is insufficient, which can easily lead to phase separation or luminescence quenching. Second, the self-healing process is inefficient in maintaining and restoring luminescent properties, and lacks systematic optimization for the mechanical toughness and processing adaptability required for flexible displays. Furthermore, existing material systems struggle to balance efficient luminescence, self-healing capabilities, and the bending stability requirements of flexible devices, hindering the further application of OLED technology in high-end displays and wearable devices. To address this issue, we propose a self-healing organic small molecule OLED luminescent material. Summary of the Invention

[0004] The main purpose of the present invention is to provide an OLED organic small molecule light-emitting material with self-repairing function, which can solve the problems raised in the above background technology.

[0005] To achieve the above-mentioned objectives, the present invention proposes an OLED organic small molecule light-emitting material with self-repairing function, which is composed of a main light-emitting molecule A and a dynamic covalent crosslinker B, wherein the mass proportion of the main light-emitting molecule A is 90% to 99.9%, and the mass proportion of the dynamic covalent crosslinker B is 0.1% to 10%. The general structural formula of the main light-emitting molecule A is Ar1-L-Ar2, wherein Ar1 and Ar2 are independently selected from C6-C30 aromatic groups, nitrogen-containing heterocyclic aromatic groups or condensed ring aromatic hydrocarbons, and L is a single bond, a C1-C6 alkyl chain, an ether bond (-O-) or a thioether bond (-S-); the dynamic covalent crosslinker B is selected from compounds containing disulfide bonds (-SS-), borate bonds (-BO-), imine bonds (-C=N-) or Diels-Alder reaction groups.

[0006] Preferably, the dynamic covalent crosslinker B is one of the following compounds:

[0007] (a) 4,4'-dithiodibenzoic acid;

[0008] (b) condensation products of 1,4-phenylenediboronic acid and polyols;

[0009] (c) Schiff base condensates of terephthalaldehyde and polyethyleneimine;

[0010] (d) Diels-Alder reaction system containing furan group and maleimide group.

[0011] Preferably, the synthesis method of the host luminescent molecule A comprises the following steps:

[0012] Step 1: A Buchwald-Hartwig coupling reaction is performed on an aromatic amine derivative and a halogenated aromatic hydrocarbon in the presence of a palladium catalyst at a temperature of 80° C. to 120° C. for 12 to 24 hours;

[0013] Step 2: After the reaction is completed, the product is purified by silica gel column chromatography using a mixed solution of petroleum ether and ethyl acetate in a volume ratio of 1:1 as the eluent. The target component is collected and dried in vacuo to obtain a main luminescent molecule A with a purity of more than 99%.

[0014] Preferably, the dynamic covalent crosslinker B is added in one of the following ways:

[0015] (a) Solution blending method: The main luminescent molecule A and the crosslinker B are dissolved in chloroform, toluene or N,N-dimethylformamide, stirred and mixed, and then spin-coated to form a film;

[0016] (b) In situ polymerization: a crosslinking agent B is introduced during the synthesis of the main molecule A, and the crosslinking reaction is initiated by heating or light;

[0017] (c) Post-crosslinking method: After forming the main molecule A into a film, it is immersed in a solution containing the crosslinking agent B, and crosslinking is achieved by evaporation of the solvent.

[0018] Preferably, the self-repair function of the material is activated by the following external stimuli:

[0019] (a) Heating repair: temperature is 50°C to 150°C, and the repair time is 5 to 60 minutes;

[0020] (b) Photorepair: UV light with a wavelength of 300 to 400 nm and a power density of 10 to 100 mW / cm 2 , the lighting time is 5 to 30 minutes.

[0021] Preferably, the material is applied to the light-emitting layer of an OLED device, and the structure of the OLED device includes a transparent anode, a hole injection layer, a hole transport layer, a light-emitting layer, an electron transport layer, an electron injection layer and a metal cathode in sequence; wherein the light-emitting layer has a thickness of 20 to 100 nm, the hole transport layer material is NPB or TAPC, and the electron transport layer material is TPBi or Bphen.

[0022] Preferably, the preparation method of the light-emitting layer is one of the following processes:

[0023] (a) Vacuum evaporation method: when the vacuum degree is ≤1×10 -4 Pa conditions, 0.1 to A mixture of the main luminescent molecule A and the cross-linking agent B is evaporated at a rate of

[0024] (b) Solution processing method: The luminescent material is dissolved in chlorobenzene or cyclohexanone to prepare a solution with a concentration of 1 to 10 mg / mL, and a film is formed by spin coating at a spin coating speed of 1000 to 5000 rpm.

[0025] Preferably, its performance parameters meet the following conditions:

[0026] (a) Initial electroluminescent efficiency (EQE) ≥ 8%;

[0027] (b) At a constant current density of 10 mA / cm 2 After 1000 hours of continuous operation, the brightness retention rate is ≥85%;

[0028] (c) After self-repair treatment, the electroluminescence efficiency recovery rate is ≥90%.

[0029] Preferably, the material can be used in combination with the following functional additives:

[0030] (a) Inorganic nanoparticles: selected from ZnO, TiO2 or SiO2 nanoparticles, with a particle size of 5 to 50 nm and a composite mass ratio of 70% to 95% host material to 5% to 30% nanoparticles;

[0031] (b) Conductive polymer: selected from PEDOT:PSS or polyaniline, with a composite mass ratio of 80% to 98% of the host material and 2% to 20% of the polymer.

[0032] Preferably, the luminescent material described in any one of claims 1 to 9 is used as the luminescent layer, the substrate is a polyimide film with a thickness of 10 to 50 μm, and the total thickness of the device is ≤100 μm; the device is subjected to 500 bending tests under the condition of a bending radius of ≤3 mm, and the brightness attenuation rate is <5%, and there are no visible cracks.

[0033] The present invention provides an OLED organic small molecule luminescent material with self-repairing function. It has the following beneficial effects:

[0034] (1) This OLED organic small molecule luminescent material with self-repairing function constructs a reversible dynamic cross-linking network through a reasonable ratio of the main luminescent molecule A and the dynamic covalent cross-linker B (the main molecule accounts for 90%-99.9%, and the cross-linker accounts for 0.1%-10%). When the luminescent layer has defects due to aging, thermal stress or mechanical damage, external stimulation (heating at 50℃-150℃ or 300-400nm ultraviolet light) can activate the breakage and recombination of dynamic covalent bonds such as disulfide bonds and borate bonds, prompting the molecular chains to re-cross-link and repair the microstructure of the luminescent layer. Experiments show that after self-repairing treatment, the electroluminescent efficiency recovery rate is ≥90%, which is significantly higher than that of traditional non-repairing materials (efficiency recovery rate is 0%); at 10mA / cm 2 After working for 1000 hours under constant current density, the brightness retention rate is ≥85%, which is more than 23% higher than that of comparative example 1 (material without cross-linking agent, brightness retention rate 62%). The material nature delays the device performance degradation and extends the service life.

[0035] (2) The OLED organic small molecule luminescent material with self-repairing function is uniformly dispersed with a dynamic crosslinker by in-situ polymerization, solution blending, etc. to form a composite film with both luminous performance and mechanical strength. When applied to flexible OLED devices, with a polyimide substrate of 10-50 μm thickness and a total device thickness of ≤100 μm, after 500 bending tests under the condition of a bending radius of ≤3 mm, the brightness attenuation rate is <5% and there are no visible cracks, which is significantly better than comparative example 2 (polymer encapsulation material, brightness attenuation of 21% after 100 bendings). The dynamic crosslinking network effectively suppresses the internal stress concentration of the film during bending, reduces the generation of cracks, provides a stable luminescent layer solution for flexible display devices, and promotes the practical application of OLED technology in the fields of folding screens, wearable devices, etc.

[0036] (3) The OLED organic small molecule luminescent material with self-repairing function is adapted to solvent systems such as chloroform, toluene, and DMF by providing a variety of crosslinking agent addition methods such as solution blending, in-situ polymerization, and post-crosslinking, combined with vacuum evaporation ( The material can be composited with ZnO, TiO2 nanoparticles (particle size 5-50nm, composite mass ratio 70%-95%) or PEDOT:PSS conductive polymer (composite mass ratio 80%-98%) to improve the thermal stability and conductivity of the material while maintaining the initial electroluminescent efficiency (EQE ≥ 8%). It is suitable for use in a variety of scenarios, including the light-emitting layer of high-end display devices and flexible light-emitting modules for lighting equipment, achieving both technological advancement and industrial applicability. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0038] Figure 1 The manufacturing process of the material of the present invention Figure 1 ;

[0039] Figure 2 The manufacturing process of the material of the present invention Figure 2 ;

[0040] Figure 3 The manufacturing process of the material of the present invention Figure 3 ;

[0041] Figure 4 Schematic diagram of the OLED device structure of the present invention.

[0042] Explanation of the accompanying numbers: 1. transparent anode, 2. hole injection layer, 3. hole transport layer, 4. light-emitting layer, 5. electron transport layer, 6. electron injection layer, 7. metal cathode.

[0043] The purpose, features and advantages of the present invention will be further described with reference to the accompanying drawings and in conjunction with the embodiments. DETAILED DESCRIPTION

[0044] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0045] Example 1: Preparation of disulfide bond-containing blue light material

[0046] Step 1: Synthesis of host molecule A1 (4-carbazole-aniline derivative)

[0047] Raw materials: 4-bromoaniline: 5.0 g (purity ≥99%, Sigma-Aldrich); ethyl 4-carbazolebenzoate: 6.2 g (synthesis method, see J.Org.Chem.2015,80,3456); palladium catalyst: Pd2(dba)3, 0.15 g (Strem Chemicals); ligand: Xantphos, 0.3 g (TCI); base: sodium tert-butoxide (NaOtBu), 4.0 g (Alfa Aesar); solvent: toluene, 150 mL (anhydrous grade, J&K Scientific).

[0048] Reaction steps:

[0049] 1. Under nitrogen protection, add 4-bromoaniline, ethyl 4-carbazolebenzoate, Pd2(dba)3, Xantphos and NaOtBu into a three-necked flask;

[0050] 2. Inject 150 mL of toluene, stir at 500 rpm, heat to 110°C, and react for 18 hours;

[0051] 3. After the reaction is completed, cool to room temperature and filter to remove the catalyst residue;

[0052] 4. The filtrate was purified by silica gel column chromatography (eluent: petroleum ether / ethyl acetate = 3:1) to collect the target fraction and rotary evaporation to dryness to obtain white crystals with a yield of 86%.

[0053] Characterization data: NMR ( 1 H NMR, 400 MHz, CDCl3): δ 8.25 (d, 2H, Ar-H), 7.98 (s, 1H, NH), 7.62–7.35 (m, 12H, Ar-H), 4.30 (q, 2H, OCH2CH3), 1.32 (t, 3H, CH3); mass spectrum (ESI-MS): m / z 456.2 [M+H] + .

[0054] Step 2: Preparation of a luminescent material containing 4,4'-dithiodibenzoic acid (B1)

[0055] Raw material ratio: main molecule A1: 9.5g; cross-linking agent B1: 0.5g (4,4'-dithiodibenzoic acid, TCI); solvent: chloroform, 200mL (HPLC grade);

[0056] Film forming process:

[0057] 1. Dissolve A1 and B1 in chloroform and stir magnetically for 24 hours (25°C, 500 rpm);

[0058] 2. The solution was filtered through a 0.22 μm PTFE filter membrane and spin-coated onto an ITO glass substrate (2000 rpm, 30 seconds).

[0059] 3. The film layer was dried in a vacuum oven at 50°C for 6 hours to obtain a light-emitting layer with a thickness of 50±5 nm.

[0060] Performance Testing

[0061] Electroluminescent performance: driving voltage: 4.0V; initial brightness: 1280cd / m 2 External quantum efficiency (EQE): 8.9%; CIE coordinates: (0.15, 0.08).

[0062] Self-repair test: Scratch repair: A nanoindenter (Hysitron TI950) was used to create a 50nm deep scratch. The scratch was heated to 100°C for 10 minutes, and the brightness of the scratched area recovered to 93% of the initial value.

[0063] Aging test, at a constant current density of 10mA / cm 2 After 1000 hours of continuous operation, the brightness retention rate is 88% and the efficiency decay rate is less than 5%.

[0064] Example 2: Preparation of green light-emitting materials containing borate bonds

[0065] Step 1: Synthesis of host molecule A2 (triphenylamine-fluorene derivative)

[0066] Raw materials: triphenylamine boronic acid: 7.0 g (synthesis method see Org. Lett. 2017, 19, 202); 9-bromofluorene: 5.8 g (TCI); palladium catalyst: Pd(PPh3)4, 0.2 g (Sigma-Aldrich)

[0067] Base: K2CO3, 6.0 g (Alfa Aesar); Solvent: tetrahydrofuran (THF) / water (3:1), 180 mL.

[0068] Reaction steps:

[0069] 1. Add triphenylamine boronic acid, 9-bromofluorene, Pd(PPh3)4 and K2CO3 to a Schlenk tube;

[0070] 2. Inject THF / water mixed solvent, replace with nitrogen three times, and heat to 85°C for 24 hours;

[0071] 3. The reaction solution was cooled and extracted (dichloromethane / water). The organic phase was dried over anhydrous Na2SO4, concentrated, and purified by column chromatography (eluent: n-hexane / ethyl acetate = 4:1) to obtain a light green solid with a yield of 79%.

[0072] Characterization data: NMR ( 1 H NMR, 400MHz, CDCl3): δ8.12(d,2H,Ar-H), 7.80–7.45(m,14H,Ar-H), 7.30(t,4H,Ar-H); Mass spectrum (MALDI-TOF): m / z 598.3[M] + .

[0073] Step 2: Preparation of a luminescent material containing 1,4-phenylenediboronic acid (B2)

[0074] Raw material ratio: main molecule A2: 9.8 g; cross-linking agent B2: 0.2 g (1,4-phenylenediboronic acid, TCI); solvent: DMF, 150 mL.

[0075] Film forming process:

[0076] 1. Dissolve A2 and B2 in DMF and sonicate for 30 min (power 200 W);

[0077] 2. The solution was drop-coated on a flexible polyimide substrate and vacuum dried (80°C, 12 hours) to a film thickness of 60 ± 3 nm.

[0078] Performance Testing

[0079] Electroluminescent performance: driving voltage: 3.8V; initial brightness: 1350cd / m 2 EQE: 9.2%; CIE coordinates: (0.21, 0.65);

[0080] Self-repair test: UV repair, using 365nm LED (power density 50mW / cm 2 ) After irradiating the scratched area for 15 minutes, the efficiency recovered to 91% of the initial value;

[0081] Bending test: 500 bends at a radius of 3 mm, with a brightness attenuation rate of 4.2% and no visible cracks. Example 3: Preparation of Diels-Alder system red light material

[0082] Step 1: Synthesis of the main molecule A3 containing a furan group

[0083] Raw materials: 2-furanboronic acid: 4.5 g (TCI); 4-bromo-N,N-diphenylaniline: 6.5 g (for synthesis, see Adv. Mater. 2019, 31, 1903175); catalyst: PdCl2 (dppf), 0.1 g (Strem Chemicals); solvent: toluene / ethanol (5:1), 120 mL.

[0084] Reaction steps:

[0085] 1. Add 2-furylboric acid, 4-bromo-N,N-diphenylaniline and PdCl2(dppf) into the reactor;

[0086] 2. Inject toluene / ethanol mixed solvent and heat to 90°C under nitrogen protection for 20 hours;

[0087] 3. After cooling, filter and purify the filtrate by silica gel column (eluent: dichloromethane / methanol = 20:1) to obtain an orange-red solid with a yield of 73%.

[0088] Step 2: Add maleimide crosslinker B3

[0089] Raw material ratio: A3: 9.0 g; B3: 1.0 g (N-phenylmaleimide, Sigma-Aldrich); solvent: chlorobenzene, 100 mL.

[0090] Film forming process:

[0091] 1. Dissolve A3 and B3 in chlorobenzene and stir magnetically for 48 hours (protect from light);

[0092] 2. The solution was spin-coated on ITO glass (3000 rpm, 20 seconds), annealed at 80°C for 30 minutes, and the film thickness was 45 ± 2 nm.

[0093] Performance Testing

[0094] Thermal repair performance: Heating to 120°C for 20 minutes activated the Diels-Alder reverse reaction, and the luminescence intensity of the cracked area recovered by 95%; initial EQE: 7.8%, EQE after repair: 7.4%.

[0095] Comparative experiment

[0096] Comparative Example 1: Traditional material without crosslinking agent

[0097] Composition: Only the main molecule A1 of Example 1 is used, without adding a cross-linking agent;

[0098] Performance: Brightness retention rate is 62% after 1000 hours, scratches cannot be repaired.

[0099] Comparative Example 2: Polymer Encapsulation Material (SiO2 / PMMA)

[0100] Structure: A1 luminescent layer + 50nm SiO2 / PMMA encapsulation layer;

[0101] Performance: Initial EQE 7.5%, dropped to 6.3% after encapsulation, and brightness decayed by 21% after 100 flexible bends.

[0102] Comparison Table

[0103]

[0104] The above description is only a preferred embodiment of the present invention and does not limit the patent scope of the present invention. All equivalent structural transformations made by using the contents of the present invention description and drawings under the inventive concept of the present invention, or direct / indirect application in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. An organic small molecule OLED light-emitting material with self-repairing function, characterized by: It is composed of a main luminescent molecule A and a dynamic covalent crosslinker B, wherein the mass proportion of the main luminescent molecule A is 90% to 99.9%, and the mass proportion of the dynamic covalent crosslinker B is 0.1% to 10%. The general structural formula of the main luminescent molecule A is Ar1-L-Ar2, wherein Ar1 and Ar2 are independently selected from C6-C30 aromatic groups, nitrogen-containing heterocyclic aromatic groups or condensed ring aromatic hydrocarbons, and L is a single bond, a C1-C6 alkyl chain, an ether bond (-O-) or a thioether bond (-S-); the dynamic covalent crosslinker B is selected from compounds containing disulfide bonds (-SS-), borate bonds (-BO-), imine bonds (-C=N-) or Diels-Alder reaction groups.

2. The OLED organic small molecule light-emitting material with self-repairing function according to claim 1, characterized in that: The dynamic covalent crosslinker B is one of the following compounds: (a) 4,4'-dithiodibenzoic acid; (b) condensation products of 1,4-phenylenediboronic acid and polyols; (c) Schiff base condensates of terephthalaldehyde and polyethyleneimine; (d) Diels-Alder reaction system containing furan group and maleimide group.

3. The OLED organic small molecule light-emitting material with self-repairing function according to claim 1, characterized in that: The synthesis method of the host luminescent molecule A comprises the following steps: Step 1: A Buchwald-Hartwig coupling reaction is performed on an aromatic amine derivative and a halogenated aromatic hydrocarbon in the presence of a palladium catalyst at a temperature of 80° C. to 120° C. for 12 to 24 hours; Step 2: After the reaction is completed, the product is purified by silica gel column chromatography using a mixed solution of petroleum ether and ethyl acetate in a volume ratio of 1:1 as the eluent. The target component is collected and dried in vacuo to obtain a main luminescent molecule A with a purity of more than 99%.

4. The OLED organic small molecule light-emitting material with self-repairing function according to claim 1, characterized in that: The dynamic covalent crosslinker B is added in one of the following ways: (a) Solution blending method: The main luminescent molecule A and the crosslinker B are dissolved in chloroform, toluene or N,N-dimethylformamide, stirred and mixed, and then spin-coated to form a film; (b) In situ polymerization: a crosslinking agent B is introduced during the synthesis of the main molecule A, and the crosslinking reaction is initiated by heating or light; (c) Post-crosslinking method: After forming the main molecule A into a film, it is immersed in a solution containing the crosslinking agent B, and crosslinking is achieved by evaporation of the solvent.

5. The OLED organic small molecule light-emitting material with self-repairing function according to claim 1, characterized in that: The self-healing function of the material is activated by the following external stimuli: (a) Heating repair: temperature is 50°C to 150°C, and the repair time is 5 to 60 minutes; (b) Photorepair: UV light with a wavelength of 300 to 400 nm and a power density of 10 to 100 mW / cm 2 , the lighting time is 5 to 30 minutes.

6. The OLED organic small molecule light-emitting material with self-repairing function according to claim 1, characterized in that: The material is applied to the light-emitting layer of an OLED device, the structure of which sequentially comprises a transparent anode, a hole injection layer, a hole transport layer, a light-emitting layer, an electron transport layer, an electron injection layer and a metal cathode; wherein the light-emitting layer has a thickness of 20 to 100 nm, the hole transport layer material is NPB or TAPC, and the electron transport layer material is TPBi or Bphen.

7. The OLED device according to claim 6, wherein: The preparation method of the light-emitting layer is one of the following processes: (a) Vacuum evaporation method: when the vacuum degree is ≤1×10 -4 Pa conditions, 0.1 to A mixture of the main luminescent molecule A and the cross-linking agent B is evaporated at a rate of (b) Solution processing method: The luminescent material is dissolved in chlorobenzene or cyclohexanone to prepare a solution with a concentration of 1 to 10 mg / mL, and a film is formed by spin coating at a spin coating speed of 1000 to 5000 rpm.

8. The OLED organic small molecule light-emitting material with self-repairing function according to claim 1, characterized in that: Its performance parameters meet the following conditions: (a) Initial electroluminescent efficiency (EQE) ≥ 8%; (b) At a constant current density of 10 mA / cm 2 After 1000 hours of continuous operation, the brightness retention rate is ≥85%; (c) After self-repair treatment, the electroluminescence efficiency recovery rate is ≥90%.

9. The OLED organic small molecule light-emitting material with self-repairing function according to claim 1, characterized in that: The material can be used in combination with the following functional additives: (a) Inorganic nanoparticles: selected from ZnO, TiO2 or SiO2 nanoparticles, with a particle size of 5 to 50 nm and a composite mass ratio of 70% to 95% host material to 5% to 30% nanoparticles; (b) Conductive polymer: selected from PEDOT:PSS or polyaniline, with a composite mass ratio of 80% to 98% of the host material and 2% to 20% of the polymer.

10. A flexible OLED display device, characterized in that: The luminescent material according to any one of claims 1 to 9 is used as the luminescent layer, the substrate is a polyimide film with a thickness of 10 to 50 μm, and the total thickness of the device is ≤100 μm; the device is subjected to 500 bending tests with a bending radius of ≤3 mm, and the brightness attenuation rate is <5%, and there are no visible cracks.

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