Excimer luminescent material based on gold complex acceptor and application thereof

Abstract

The present application relates to the excimer luminescent material based on gold complex acceptor and its application. The excimer luminescent material is constructed by gold complex acceptor material and organic donor material, which is applied in organic light emitting diode, has lower driving voltage and higher luminescent efficiency, and can improve the service life of the device, and has potential application in the field of organic electroluminescent device. The present application also provides an organic electroluminescent device, which comprises a cathode, an anode and an organic layer, the organic layer is one or more of a hole injection layer, a hole transport layer, a light emitting layer, a hole blocking layer, an electron transport layer and an electron injection layer, and at least one layer of the organic layer contains a compound in structural formula (I) and (II).

Description

Technical Field

[0001] This invention relates to the field of luminescent materials, specifically to excitocomplex luminescent materials containing gold complex acceptor materials and their application in organic light-emitting diodes. Background Technology

[0002] Organic optoelectronic devices include, but are not limited to, the following: organic light-emitting diodes (OLEDs), organic thin-film transistors (OTFTs), organic photovoltaic devices (OPVs), light-emitting electrochemical cells (LCEs), and chemical sensors.

[0003] In recent years, OLEDs, as a lighting and display technology with enormous application potential, have received widespread attention from academia and industry. OLED devices possess characteristics such as self-emission, wide viewing angle, short response time, and the ability to fabricate flexible devices, making them strong contenders for next-generation display and lighting technologies. However, OLEDs still suffer from low efficiency and short lifespan, requiring further research. High-efficiency, long-lifespan OLED devices typically require optimized combinations of device structure and functional layer materials. Common functional layer materials include: hole injection materials, hole transport materials, electron injection materials, electron transport materials, electron blocking materials, host materials, and luminescent materials. To fabricate OLEDs with better luminous efficiency and longer device lifespan, academia and industry have been committed to developing novel luminescent materials.

[0004] Excimer composite luminescent materials singlet-triplet bandgap (ΔE) ST With a relatively small exciton voltage (<0.2 eV), triplet excitons can be converted into singlet excitons via reverse system-reversal crossover (RISC) to achieve delayed fluorescence emission (TADF), resulting in an internal quantum efficiency of up to 100%. Furthermore, exciton complexes can reduce the device's driving voltage, attracting widespread attention from the scientific and industrial communities. Currently, reported exciton complex systems are mainly based on purely organic electron donor and acceptor materials. The photophysical and electrochemical properties of common hole transport, electron transport, and bipolar materials have been reported in detail. Combining these materials can achieve exciton complex luminescence, with device external quantum efficiencies (EQE) mostly ranging from 5% to 20%. The delayed fluorescence lifetime (τ) of these purely organic systems... DF The exciton length is generally long, which easily leads to the annihilation of luminescent excitons and adversely affects the efficiency and stability of devices. Theoretically, by constructing exciton complex systems using transition metal complexes (such as iridium, platinum, gold, palladium, and copper), high-efficiency luminescent materials can be obtained by utilizing the heavy atom effect of metals and the interaction between the metal center and the ligand. However, compared with the aforementioned pure organic donor-acceptor combination systems, the TADF-type exciton complex systems of metal complexes have not yet received sufficient attention from the academic community, and there are few related reports. Summary of the Invention

[0005] To address the aforementioned problems in the existing technology, this invention provides an excimer compound luminescent material composed of a gold complex acceptor material and an organic donor material. This material exhibits excellent photoelectric performance and device stability when applied to organic light-emitting diodes.

[0006] The present invention also provides an organic light-emitting diode based on the excimer compound luminescent material.

[0007] An excimer luminescent material is composed of 1%-10% by mass of a gold complex acceptor material and 99%-90% by mass of an organic donor material. The gold complex acceptor material is a compound having the structure of formula (I):

[0008]

[0009] in:

[0010] R 1 To R 4 Each is independently selected from: hydrogen, deuterium, halogen, aldehyde, cyano, sulfonyl, substituted or unsubstituted alkyl with 1-6 carbon atoms, substituted or unsubstituted cycloalkyl with 3-20 cyclic carbon atoms, substituted or unsubstituted alkoxy with 1-20 carbon atoms, substituted or unsubstituted aryl with 6-30 carbon atoms, substituted or unsubstituted heteroaryl with 3-30 carbon atoms, or any two adjacent substituents linked or fused into a ring;

[0011] a1 and a2 are integers from 1 to 4, and when a1 is 2 or greater, the two R values ​​are... 1 The groups can be the same or different from each other, and when a2 is 2 or greater, the two R groups can be... 2 The functional groups may be the same as or different from each other;

[0012] a3 and a4 are integers from 1 to 5, and when a3 is 2 or greater, the two R values ​​are... 3 The groups can be the same or different from each other, and when a4 is 2 or greater, the two R groups can be... 4 The functional groups may be the same as or different from each other;

[0013] The organic donor material has the structure of formula (2):

[0014]

[0015] R is selected from: hydrogen, deuterium, substituted or unsubstituted alkyl groups having 1-10 carbon atoms, substituted or unsubstituted cycloalkyl groups having 3-20 cyclic carbon atoms, substituted or unsubstituted aryl groups having 6-30 carbon atoms; substituted or unsubstituted heteroaryl groups having 3-30 carbon atoms, or any two adjacent substituents linked or fused into a ring.

[0016] The heteroatom in the heteroaryl group is one or more of N, S, and O;

[0017] The substitution is achieved by halogen, amino, C1-C4 alkylamino, C6-C20 aromaticamino, cyano, or C1-C4 alkyl.

[0018] Preferred: R 2 It is independently selected from hydrogen.

[0019] R 1 R 3 To R 4 Each is independently selected from: hydrogen, deuterium, halogen, aldehyde, cyano, substituted or unsubstituted alkyl groups having 1-4 carbon atoms, substituted or unsubstituted cycloalkyl groups having 3-10 cyclic carbon atoms, substituted or unsubstituted aryl groups having 6-10 carbon atoms, and substituted or unsubstituted heteroaryl groups having 3-10 carbon atoms, wherein R 1 R 3 To R 4 The substitution in it is replaced by halogen, cyano or C1-C4 alkyl.

[0020] The following are examples of gold complex acceptor material molecules according to the present invention, but are not limited to the structures listed:

[0021]

[0022]

[0023] Preferably, the composition consists of 3%-7% by mass of the above-mentioned gold complex acceptor material and 97%-93% by mass of organic donor material molecules, wherein R is selected from: hydrogen, deuterium, substituted or unsubstituted alkyl with 1-6 carbon atoms, substituted or unsubstituted cycloalkyl with 3-10 cyclic carbon atoms, substituted or unsubstituted aryl with 6-20 carbon atoms; substituted or unsubstituted heteroaryl with 3-20 carbon atoms; wherein the substitution in R is by substituted amino, C1-C4 alkylamino, C6-C20 arylamino or C1-C4 alkyl.

[0024] Further preferred: the composition consists of 5% gold complex acceptor material and 95% organic donor material by mass ratio, wherein R in the organic donor material is selected from: hydrogen, deuterium, substituted or unsubstituted alkyl with 1-6 carbon atoms, substituted or unsubstituted cycloalkyl with 3-10 cyclic carbon atoms, substituted or unsubstituted aryl with 6-10 carbon atoms; substituted or unsubstituted heteroaryl with 3-20 carbon atoms; wherein the substitution in R is by being substituted with C6-C20 arylamine or C1-C4 alkyl.

[0025] The following are examples of organic donor materials according to the present invention, but are not limited to the structures listed:

[0026]

[0027]

[0028] The present invention also provides an application of the excitocomplex constructed based on the above-mentioned donor and acceptor combination in organic optoelectronic devices, wherein the optoelectronic devices include, but are not limited to, organic light-emitting diodes (OLEDs), organic thin-film transistors (OTFTs), organic photovoltaic devices (OPVs), light-emitting electrochemical cells (LCEs), and chemical sensors, preferably OLEDs.

[0029] Organic light-emitting diodes (OLEDs) include a cathode, an anode, and an organic layer, wherein the organic layer is one or more of a hole injection layer, a hole transport layer, an emissive layer, a hole blocking layer, an electron injection layer, and an electron transport layer, and these organic layers need not be present in every layer; at least one of the hole injection layer, hole transport layer, hole blocking layer, electron injection layer, emissive layer, and electron transport layer contains the excitocomplex.

[0030] The excitocomplex serves as the luminescent material in the luminescent layer.

[0031] The total thickness of the organic layer of the device of the present invention is 1-1000 nm, preferably 1-500 nm, and more preferably 5-300 nm.

[0032] The organic layer can be formed into a thin film by evaporation or solution method.

[0033] The series of luminescent materials based on gold complex acceptors and organic donors disclosed in this invention have shown high luminous efficiency and have the potential to be applied to commercial organic light-emitting diode devices.

[0034] Using the excimer complex of the present invention as the luminescent material of organic electroluminescent optoelectronic devices has the advantages of low device start-up voltage, high luminous efficiency, and long lifetime. Attached Figure Description

[0035] Figure 1 This is a structural diagram of the organic light-emitting diode device of the present invention.

[0036] Where 10 represents the glass substrate, 20 represents the anode, 30 represents the hole injection layer, 40 represents the hole transport layer, 50 represents the light-emitting layer, 60 represents the electron transport layer, 70 represents the electron injection layer, and 80 represents the cathode. Detailed Implementation

[0037] This invention does not require specific methods for synthesizing the materials. The following examples are provided for more detailed description of the invention, but are not limited thereto. Unless otherwise specified, all raw materials used in the following synthesis are commercially available products.

[0038] Example 1: Synthesis of Complex 4

[0039] Synthesis of Intermediate 1 (1-1)

[0040]

[0041] Compound 1b (380 mg, 2.45 mmol), tetrachloroauric acid trihydrate (804 mg, 2.04 mmol), and water (10 mL) were added to a high-pressure reactor. The reaction was carried out at 140 °C for 30 hours. After the reaction was completed, the mixture was filtered, and the solid was dried under vacuum to give 713 mg of a pale yellow solid, with a yield of 83%.

[0042] Synthesis of complex 4 (1-2):

[0043]

[0044] Intermediate 1 (450 mg, 1.07 mmol), compound 4a (418 mg, 2.35 mmol), palladium acetate (22 mg, 0.21 mmol), tri-tert-butylphosphine tetrafluoroborate (81 mg, 0.28 mmol), anhydrous potassium carbonate (1.10 g, 7.98 mmol), toluene (10 mL), and isopropanol (10 mL) were added to a single-necked flask. The reaction was carried out at 40 °C for 12 hours under nitrogen protection. After the reaction was completed, the solvent was evaporated to dryness, dissolved in 100 mL of dichloromethane, extracted with 75 mL of water, and the organic phase was evaporated to dryness. The residue was separated by column chromatography to obtain a white solid powder, 421 mg, in a yield of 64%. MS (m / z): 618.23 (M+1).

[0045] Example 2: Synthesis of Complex 17

[0046]

[0047] Intermediate 1 (480 mg, 1.14 mmol), compound 17a (375 mg, 2.50 mmol), palladium acetate (24 mg, 0.23 mmol), tri-tert-butylphosphine tetrafluoroborate (87 mg, 0.30 mmol), anhydrous potassium carbonate (1.11 g, 8.05 mmol), toluene (10 mL), and isopropanol (10 mL) were added to a single-necked flask. The reaction was carried out at 40 °C for 12 hours under nitrogen protection. After the reaction was completed, the solvent was evaporated to dryness, dissolved in 100 mL of dichloromethane, extracted with 75 mL of water, and the organic phase was evaporated to dryness. The residue was separated by column chromatography to obtain a white solid powder, 398 mg, in a yield of 62%. MS (m / z): 562.11 (M+1).

[0048] Example 3: Synthesis of Complex 37

[0049]

[0050] Intermediate 1 (420 mg, 0.995 mmol), compound 37a (401 mg, 2.19 mmol), palladium acetate (20 mg, 0.19 mmol), tri-tert-butylphosphine tetrafluoroborate (80 mg, 0.28 mmol), anhydrous potassium carbonate (1.10 g, 7.98 mmol), toluene (10 mL), and isopropanol (10 mL) were added to a single-necked flask. The reaction was carried out at 40 °C for 12 hours under nitrogen protection. After the reaction was completed, the solvent was evaporated to dryness, dissolved in 100 mL of dichloromethane, extracted with 75 mL of water, and the organic phase was evaporated to dryness. The residue was separated by column chromatography to obtain a white solid powder, 405 mg, in 65% yield. MS (m / z): 628.06 (M+1)

[0051] Example 4: Synthesis of Complex 44

[0052]

[0053] 4-1 Synthesis of compound 3b:

[0054] Compound 2b (2.80 g, 17.72 mmol), compound 2a (4.04 g, 21.27 mmol), dichlorodi-tert-butyl-(4-dimethylaminophenyl)phosphine palladium(II) (601 mg, 0.85 mmol), tetrahydrofuran (75 mL), and an aqueous solution of potassium carbonate (25 mL, 2 mol / L) were added to a two-necked flask. The mixture was refluxed at 80 °C for 12 hours under nitrogen protection. After the reaction was complete, the solvent was evaporated to dryness, dissolved in 300 mL of dichloromethane, extracted with 150 mL of water, and the organic phase was evaporated to dryness. The residue was separated by column chromatography to obtain a white solid powder, 3.57 g, in 90% yield. MS (m / z): 224.07 (M+1)

[0055] Synthesis of intermediate 2 (4-2):

[0056] Compound 2b (480 mg, 2.15 mmol), tetrachloroauric acid trihydrate (706 mg, 1.79 mmol), and water (10 mL) were added to a high-pressure reactor. The reaction was carried out at 140 °C for 30 hours. After the reaction was completed, the mixture was filtered, and the solid was dried under vacuum to give 702 mg of a brown solid, with a yield of 80%.

[0057] Synthesis of complex 4-3 44:

[0058]

[0059] Intermediate 2 (540 mg, 1.10 mmol), compound 4a (432 mg, 2.42 mmol), palladium acetate (22 mg, 0.21 mmol), tri-tert-butylphosphine tetrafluoroborate (81 mg, 0.28 mmol), anhydrous potassium carbonate (1.10 g, 7.98 mmol), toluene (10 mL), and isopropanol (10 mL) were added to a single-necked flask. The reaction was carried out at 40 °C for 12 hours under nitrogen protection. After the reaction was completed, the solvent was evaporated to dryness, dissolved in 100 mL of dichloromethane, extracted with 75 mL of water, and the organic phase was evaporated to dryness. The residue was separated by column chromatography to obtain a white solid powder, 538 mg, in 71% yield. MS (m / z): 686.24 (M+1).

[0060] Example 5: Synthesis of Complex 45

[0061]

[0062] Synthesis of compound 4b (5-1):

[0063] Compound 2b (2.10 g, 13.29 mmol), compound 3a (2.34 g, 15.95 mmol), dichlorodi-tert-butyl-(4-dimethylaminophenyl)phosphine palladium(II) (601 g, 0.85 mmol), tetrahydrofuran (75 mL), and an aqueous solution of potassium carbonate (25 mL, 2 mol / L) were added to a two-necked flask. The mixture was refluxed at 80 °C for 12 hours under nitrogen protection. After the reaction was complete, the solvent was evaporated to dryness, dissolved in 300 mL of dichloromethane, extracted with 150 mL of water, and the organic phase was evaporated to dryness. The residue was separated by column chromatography to obtain a white solid powder, 2.09 g, in 87% yield. MS (m / z): 181.07 (M+1)

[0064] Synthesis of intermediate 3 (5-2):

[0065] Compound 4b (440 mg, 2.44 mmol), tetrachloroauric acid trihydrate (801 mg, 2.03 mmol), and water (10 mL) were added to a high-pressure reactor. The reaction was carried out at 140 °C for 30 hours. After the reaction was completed, the mixture was filtered, and the solid was dried under vacuum to give 765 mg of a brown solid, with a yield of 84%.

[0066] Synthesis of complex 45 of 5-3:

[0067]

[0068] Intermediate 3 (510 mg, 1.14 mmol), compound 45a (306 mg, 2.51 mmol), palladium acetate (22 mg, 0.21 mmol), tri-tert-butylphosphine tetrafluoroborate (81 mg, 0.28 mmol), anhydrous potassium carbonate (1.10 g, 7.98 mmol), toluene (10 mL), and isopropanol (10 mL) were added to a single-necked flask. The reaction was carried out at 40 °C for 12 hours under nitrogen protection. After the reaction was completed, the solvent was evaporated to dryness, dissolved in 100 mL of dichloromethane, extracted with 75 mL of water, and the organic phase was evaporated to dryness. The residue was separated by column chromatography to obtain a white solid powder, 447 mg, in 74% yield. MS (m / z): 531.17 (M+1).

[0069] Example 6: Synthesis of donor material D6

[0070]

[0071] Under nitrogen protection, D6-1 (1.12 g, 3.24 mmol), 3,5-di-tert-butyliodobenzene (3.59 g, 11.35 mmol), Pd2(dba)3 (200 mg, 0.22 mmol), tri-tert-butylphosphine (0.5 mL, 1 M), and sodium tert-butoxide (1.25 g, 12.97 mmol) were dissolved in toluene (50 mL) and reacted overnight at 120 °C. After cooling to room temperature, water was added, and the mixture was extracted with dichloromethane. The solvent was removed under reduced pressure, and the residue was subjected to silica gel column chromatography to give 1.06 g of a pale yellow solid, yield 36%. MS (m / z): 910.62 (M+1)

[0072] Those skilled in the art should understand that the above preparation methods are only a few exemplary examples, and those skilled in the art can obtain other compound structures of the present invention by improving them.

[0073] Experimental example:

[0074] Examples 7-11 and Comparative Examples 1-8:

[0075] Mixed solid-state films doped with gold complexes (4, 17, 37, 44, 45) and organic donors (D6) were prepared using a solution method, with a weight ratio of complex-acceptor / D6 = 5% / 95%. Solid-state films doped with organic acceptor TRZ (structure shown below) and organic donors (D6) were also prepared using a solution method, with a weight ratio of complex-donor / organic donor = 5% / 95%. Solid-state films containing gold complexes, TRZ, or donor D6 were also prepared using a solution method. The photophysical properties of the above films are listed in Table 1.

[0076]

[0077] Table 1

[0078]

[0079] Solid-state films of complexes 4, 17, 37, 44, 45, and TRZ all exhibited weak luminescence, while the solid-state film of donor material D6 showed relatively low luminescence efficiency. The complex-acceptor material and the organic donor material, after doping, emitted stronger light, indicating the formation of an excitocomplex. The excitocomplex formed by the organic donor and complex-acceptor materials in this invention is significantly more efficient than the excitocomplex formed by the organic donor (D6) and organic acceptor (TRZ), and also exhibits a shorter excited-state lifetime, confirming the feasibility of constructing high-performance excitocomplex luminescent materials using gold complex-acceptor materials.

[0080] Example 12:

[0081] Organic light-emitting diodes (OLEDs) are fabricated using an excitocomplex luminescent material constructed from a mixture of donor and acceptor materials of the present invention. The device structure is shown in [reference needed]. Figure 1 .

[0082] First, the transparent conductive ITO glass substrate 10 (with an anode 20 on it) is washed sequentially with detergent solution and deionized water, ethanol, acetone, and deionized water, and then treated with oxygen plasma for 30 seconds.

[0083] Then, a 10 nm thick HATCN layer was deposited on ITO as a hole injection layer 30.

[0084] Then, the compound HT is evaporated to form a 40 nm thick hole transport layer 40.

[0085] Then, a 20 nm thick light-emitting layer 50 is formed on the hole transport layer, which is composed of a mixture of gold complex 4 (5%) and D6 (95%).

[0086] Then, a 40 nm thick AlQ3 layer is deposited on the light-emitting layer as an electron transport layer 60.

[0087] Finally, 1 nm LiF was deposited as the electron injection layer 70 and 100 nm Al was deposited as the device cathode 80.

[0088] Example 13: Organic light-emitting diodes were prepared by replacing complex 4 with complex 17 using the method described in Example 12.

[0089] Example 14: Organic light-emitting diodes were prepared by replacing complex 4 with complex 37 using the method described in Example 12.

[0090] Example 15: Organic light-emitting diodes were prepared by replacing complex 4 with complex 44 using the method described in Example 12.

[0091] Example 16: Organic light-emitting diodes were prepared by replacing complex 4 with complex 45 using the method described in Example 12.

[0092] Comparative Example 9:

[0093] Organic light-emitting diodes were prepared by replacing complex 4 with TRZ using the method described in Example 12.

[0094] The structural formulas of HATCN, HT, and AlQ3 in the device are as follows:

[0095]

[0096] The organic electroluminescent devices in Examples 12-16 and Comparative Example 9 at 10 mA / cm 2 The device performance at current density is listed in Table 2:

[0097] Table 2

[0098]

[0099] As shown in Table 2, under the same conditions, the gold complex acceptor material of this invention, combined with an organic donor, exhibits lower driving voltage and higher luminous efficiency when applied to organic light-emitting diodes (OLEDs). Furthermore, the OLEDs based on the complexes of this invention demonstrate significantly better device lifetimes than the excimer composite luminescent materials in the comparative examples, indicating promising application prospects.

[0100] The above-described embodiments are merely examples and are not intended to limit the scope of the invention. Without departing from the spirit of the invention, various materials and structures in this invention can be replaced with other materials and structures. It should be understood that those skilled in the art can make many modifications and variations based on the concept of the invention without creative effort. Therefore, technical solutions that can be obtained by those skilled in the art through analysis, reasoning, or partial research based on the prior art should all be within the scope of protection defined by the claims.

Claims

1. An excimer complex comprising 1%-10% by mass of a gold complex acceptor material and 99%-90% by mass of an organic donor material, wherein the gold complex acceptor material is a compound having the structure of formula (I): （I） in: R 1 To R 4 Each is independently selected from: hydrogen, deuterium, halogen, aldehyde, cyano, substituted or unsubstituted alkyl groups having 1-6 carbon atoms; a1 and a2 are integers from 1 to 4, and when a1 is 2 or greater, the two R values ​​are... 1 The groups can be the same or different from each other, and when a2 is 2 or greater, the two R groups can be... 2 The functional groups may be the same as or different from each other; a3 and a4 are integers from 1 to 5, and when a3 is 2 or greater, the two R values ​​are... 3 The groups can be the same or different from each other, and when a4 is 2 or greater, the two R groups can be... 4 The functional groups may be the same as or different from each other; The organic donor material is a compound having the structure of formula (2): （2） R is selected from: substituted or unsubstituted aryl groups having 6-20 carbon atoms; The substitution is achieved by halogen, cyano, or C1-C4 alkyl groups.

2. The excimer composite luminescent material according to claim 1, wherein R 2 It is independently selected from hydrogen.

3. The excimer composite luminescent material according to claim 2, wherein R 1 R 3 To R 4 Each is independently selected from: hydrogen, deuterium, halogen, aldehyde, cyano, substituted or unsubstituted alkyl groups having 1-4 carbon atoms, wherein R 1 R 3 To R 4 The substitution in it is replaced by halogen, cyano or C1-C4 alkyl.

4. The excitocomplex according to claim 1, wherein the gold complex acceptor material has one of the following structures: 。 5. The excitocomplex according to any one of claims 1-4, comprising 3%-7% by mass of gold complex acceptor material and 97%-93% by mass of organic donor material, wherein R in the organic donor material is selected from: substituted or unsubstituted aryl groups having 6-20 carbon atoms; wherein the substitution in R is C1-C4 alkyl.

6. The excitocomplex according to claim 5, comprising 5% gold complex acceptor material and 95% organic donor material by mass ratio, wherein R in the organic donor material is selected from: substituted or unsubstituted aryl groups having 6-10 carbon atoms; wherein the substitution in R is C1-C4 alkyl groups.

7. The excitocomplex according to claim 1, wherein the organic donor material has one of the following structures: 。 8. The application of the excimer complex according to any one of claims 1-7 in an organic optoelectronic device, wherein the organic optoelectronic device is an organic light-emitting diode (OLED).

9. An organic light-emitting diode (OLED) comprising a cathode, an anode, and an organic layer, wherein the organic layer is one or more layers selected from a hole injection layer, a hole transport layer, a light-emitting layer, a hole blocking layer, an electron injection layer, and an electron transport layer, and at least one of the hole injection layer, hole transport layer, hole blocking layer, electron injection layer, light-emitting layer, and electron transport layer contains an excimer complex as described in any one of claims 1-7.

10. The organic light-emitting diodes (OLEDs) according to claim 9, wherein the excimer compound serves as a light-emitting material in the light-emitting layer.

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