Red light-near infrared organic material based on triptycene bridging and preparation method and application thereof

Abstract

The invention provides a red light-near infrared organic material based on triptycene bridging and a preparation method and application thereof, and belongs to the technical field of organic electroluminescent materials and devices, and the obtained red light-near infrared organic material based on triptycene bridging is orderly arranged under the synergistic effect of triptycene intermediate bridging and intermolecular hydrogen bonds. The compound has good carrier transport capability, solubility, thermal stability and excellent film-forming property, has the characteristics of short delayed fluorescence lifetime and high photoluminescence quantum efficiency in both solution and solid film states, is especially suitable for a solution method OLED device, and can realize excellent electroluminescent performance.

Description

Technical Field

[0001] The invention belongs to the technical field of organic electroluminescent materials and devices, and in particular relates to a red-near infrared organic material based on triptycene bridging, and a preparation method and application thereof. Background Art

[0002] Since the beginning of the 21st century, organic light-emitting diodes (OLEDs), as the third generation of new display technology, have great application prospects in the fields of display and solid light sources due to their many advantages such as full solid state, self-luminescence, wide viewing angle, fast response speed, low driving voltage, low energy consumption, and flexible devices. They have always received great attention from governments of various countries and international academic and industrial circles. In particular, red and near-infrared (NIR) organic materials and devices with delayed fluorescence characteristics have shown great demand and key roles in important fields such as information security and life health, and have received extensive attention from academic and industrial circles, further expanding the research field of OLED technology.

[0003] In recent years, solution-processed delayed fluorescent materials have gradually become one of the research hotspots of delayed fluorescent materials due to their great potential in large-area, low-cost OLED products. At present, the external quantum efficiency of solution-processed delayed fluorescent materials in the blue, green and orange regions exceeds 30%, and they have achieved good development. However, as an indispensable component of full-color luminescence, the development of red and near-infrared delayed fluorescent materials lags behind significantly. At present, the maximum external quantum efficiency of the reported red OLED (spectral peak = 594nm) based on single-molecule delayed fluorescent materials is about 24.7%; the maximum external quantum efficiency of the red OLED based on the exciplex system of intermolecular charge transition is only 10.0%. However, with the increase of the emission wavelength, the efficiency of OLED devices using solution-processed delayed fluorescent materials is sharply reduced. When the spectral peak reaches above 800nm, related near-infrared OLED devices are rarely reported, which seriously limits the application of thermally activated delayed fluorescent materials in the field of OLED. This is because red / near-infrared thermally activated delayed fluorescent materials are prone to severe intermolecular aggregation and exciton quenching when used in solution-processed OLEDs, resulting in poor performance of OLED devices.

[0004] Therefore, it is particularly important to design and synthesize red-near-infrared thermally activated delayed fluorescent materials with good solubility, high film-forming quality and short excited state lifetime. Summary of the invention

[0005] In view of the poor performance of solution-process OLED devices based on red light / near-infrared thermally activated delayed fluorescence materials, the present invention provides a red light-near-infrared organic material based on triptycene bridging and a preparation method and application thereof, which has excellent solubility, thermal stability and film-forming properties, as well as a short delayed fluorescence lifetime and a high photoluminescence quantum efficiency. When applied to solution-process OLED devices, excellent electroluminescent performance can be achieved.

[0006] In order to achieve the above purpose, the technical method adopted by the present invention is as follows:

[0007] A red-near infrared organic material based on triptycene bridging, the structure of which is shown in formula (I):

[0008]

[0009] Wherein, R1 is selected from phenoxazine, phenothiazine, phenoxazine derivatives, phenothiazine derivatives, and substituted heteroaryl.

[0010] Furthermore, the substituted heteroaryl group is specifically a structure of the following formula (II) to formula (X):

[0011]

[0012] Furthermore, the red-near infrared organic material based on triptycene bridging is specifically a material of the following formulas A-1 to A-15:

[0013]

[0014] A method for preparing a red-near infrared organic material based on triptycene bridging comprises the following steps:

[0015] Step 1: Performing a ring-closing reaction on 2-bromoanthracene and a 2-amino-5-iodobenzoic acid derivative to obtain an intermediate compound C1;

[0016] Step 2, the intermediate compound C1 and the donor group derivative substituent R1 undergo a carbon-carbon coupling reaction under the action of a first catalyst to obtain an intermediate compound C2;

[0017] Step 3, performing ester substitution on the intermediate compound C2 to obtain the intermediate compound C3 through esterification reaction;

[0018] Step 4: Carry out carbonyl protection reaction based on phenanthrene-9,10-dione and 4-bromobenzene-1,2-diamine to prepare intermediate compound C4;

[0019] Step 5: The intermediate compounds C3 and C4 react under the action of a second catalyst to obtain the red-near infrared organic material based on triptycene bridging.

[0020] Furthermore, the intermediate compounds C1, C2, C3 and C4 are specifically materials with the following structures:

[0021]

[0022] Furthermore, the specific process of step 1 is:

[0023] Under nitrogen protection, a 2-bromoanthracene solution is added to a three-necked flask with a stirring magnet, and the temperature is raised to 80-110° C. to dissolve the 2-bromoanthracene; at the same time, a 2-amino-5-iodobenzoic acid solution is added to one end of the three-necked flask, and an isoamyl nitrite solution is added to the other end, and the dripping speed of the isoamyl nitrite solution is controlled to be slightly faster than that of the 2-amino-5-iodobenzoic acid solution, and the reaction is maintained at 80-110° C.; after the reaction is completed, the intermediate compound C1 is obtained after sequentially crude purification, drying, purification, recrystallization, suction filtration and drying; wherein the molar ratio of 2-bromoanthracene to 2-amino-5-iodobenzoic acid and isoamyl nitrite is 1:2-3:5-8.

[0024] Furthermore, the solvent of the 2-amino-5-iodobenzoic acid solution is tetrahydrofuran, and the solvents of the 2-bromoanthracene solution and the isoamyl nitrite solution are both ethylene dichloride.

[0025] Furthermore, the specific process of step 2 is:

[0026] Under nitrogen protection, an intermediate compound C1, a donor group derivative substituent R1, a carbonate, and a first reaction catalyst are added in sequence to a double-necked bottle with a stirring magnet in a molar ratio of 1:1.1-2:3-5:0.1-0.3. After nitrogen is replaced several times, the first organic solvent is injected, and the obtained first mixed solution is refluxed at an oil bath temperature of 180-220°C for 18-36h. After that, the first organic solvent is removed by an oil pump, and after purification, recrystallization, filtration and drying in sequence, an intermediate compound C2 is obtained; wherein, the concentration of the intermediate compound C1 in the first mixed solution is not less than 0.0045mol / L.

[0027] Furthermore, the first reaction catalyst is cuprous iodide and 18-crown-6, and the first organic solvent is o-dichlorobenzene.

[0028] Furthermore, the specific process of step 3 is:

[0029] Under nitrogen protection, an intermediate compound C2, bipyraclostrobin, acetate and a palladium catalyst are added in sequence to a double-necked bottle with a stirring magnet in a molar ratio of 1:1 to 1.5:3 to 5:0.1 to 0.3, and a second organic solvent is injected. The obtained second mixed solution is reacted at 80 to 110° C. After the reaction is completed, the intermediate compound C3 is obtained after sequential crude purification, drying, purification, recrystallization, suction filtration and drying; wherein the concentration of the intermediate compound C3 in the second mixed solution is not less than 0.033 mol / L.

[0030] Furthermore, the second organic solvent is 1,4-dioxane.

[0031] Furthermore, the specific process of step 4 is:

[0032] Under nitrogen protection, 1,10-phenanthroline-5,6-dione and 4-bromo-o-phenylenediamine are added in sequence in a double-necked bottle with a stirring magnet in a molar ratio of 1:1 to 3, and glacial acetic acid is injected. The obtained third mixed solution is reacted at 100 to 130° C. After the reaction is completed, the intermediate compound C4 is obtained after sequential crude purification, drying, purification, recrystallization, suction filtration and drying; wherein the concentration of the intermediate compound C4 in the third mixed solution is not less than 0.05 mol / L.

[0033] Furthermore, the specific process of step 5 is:

[0034] Under nitrogen protection, an intermediate compound C3, an intermediate compound C4, acetate and a palladium catalyst are added in sequence into a double-necked bottle with a stirring magnet, and the molar ratio thereof is 1:1-1.5:3-5:0.1-0.3, and a third organic solvent is injected. The resulting fourth mixed solution is reacted at 80-110° C. After the reaction is completed, the red-near infrared organic material based on triptycene bridging is purified; wherein the concentration of the intermediate compound C3 in the fourth mixed solution is 0.033 mol / L.

[0035] Furthermore, the third organic solvent is 1,4-dioxane.

[0036] Furthermore, the red-near infrared organic material based on triptycene bridging can be dissolved in common organic solvents such as dichloromethane, toluene, chlorobenzene, N,N-dimethylformamide, and dimethyl sulfoxide.

[0037] The present invention also provides application of the red-near infrared organic material based on triptycene bridging in a solution-processed organic electroluminescent device.

[0038] Furthermore, the solution-processed organic electroluminescent device comprises an anode, a hole transport layer, a light-emitting layer, an electron transport layer and a cathode stacked in sequence; wherein the light-emitting layer is composed of the red-near infrared organic material based on triptycene bridging doped in a host material.

[0039] Furthermore, the doping concentration of the red-near infrared organic material based on triptycene bridging in the light-emitting layer is 10-100 wt %.

[0040] Furthermore, the hole transport layer, the light emitting layer and the electron transport layer are prepared by spin coating, inkjet printing or large-area scraping.

[0041] Furthermore, the anode is any one of indium tin oxide (ITO) or indium zinc oxide (ITZ); the hole transport layer is a hole transport material with a suitable triplet energy level and a highest occupied orbital energy level, wherein the hole transport material for preparing a solution method device is a PEDOT:PSS (8000) solution with good hole transport ability; the electron transport material is a pyridine derivative-based compound 3,3'-[5'-[3-(3-pyridyl)phenyl][1,1':3',1"-terphenyl]-3,3"-diyl]bipyridine (TmPyPb); the cathode is any one of Al, Ag, Au or Liq (8-hydroxyquinoline lithium) / Al, LiF (lithium fluoride) / Al, MgZnO (magnesium zinc oxide) / Al.

[0042] Furthermore, the solution-processed organic electroluminescent device is tested under an external bias voltage.

[0043] Compared with the prior art, the present invention has the following beneficial effects:

[0044] 1. The present invention proposes a red-near infrared organic material based on triptycene bridging, a preparation method and an application thereof. The material is orderly arranged under the synergistic effect of triptycene intermediate bridging and intermolecular hydrogen bonding (i.e., intermolecular hydrogen bonding interaction formed between phenazine derivative acceptor fragments and common donor fragments on the same molecule), has good carrier transport capability, excellent solubility, thermal stability and film-forming properties, and has the characteristics of short delayed fluorescence lifetime and high photoluminescence quantum efficiency in both solution and solid film states. The material is particularly suitable for solution-processed OLED devices and can achieve excellent electroluminescent performance;

[0045] 2. The red-near infrared organic material based on triptycene bridging proposed in the present invention has a completely planar conjugated structure and has strong π electron-withdrawing properties, which can meet the red light-emitting requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. 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 these drawings without paying creative work.

[0047] Figure 1 This is an ultraviolet spectrum of the triptycene-bridged red-near infrared organic material having structure A-1 obtained in Example 1 of the present invention and its constituent components at room temperature;

[0048] Figure 2 The fluorescence spectra of the red-near infrared organic material based on triptycene bridging with structure A-1 obtained in Example 1 of the present invention at different concentrations;

[0049] Figure 3 The fluorescence spectrum of the triptycene-bridged red-near infrared organic material having structure A-1 obtained in Example 1 of the present invention and its constituent components;

[0050] Figure 4 The performance diagram of the solution-processed OLED device doped in the CBP main body obtained in Example 1 of the present invention; wherein (a) is a voltage-brightness-current density curve; (b) is a brightness-power efficiency-external quantum efficiency curve; (c) is a normalized electroluminescence spectrum;

[0051] Figure 5 The performance diagram of the solution-processed OLED device obtained in Example 1 of the present invention and not doped in the CBP main body; wherein (a) is a voltage-brightness-current density curve; (b) is a brightness-power efficiency-external quantum efficiency curve; (c) is a normalized electroluminescence spectrum;

[0052] Figure 6 This is an ultraviolet spectrum of the triptycene-bridged red-near infrared organic material having structure A-2 obtained in Example 2 of the present invention and its constituent components at room temperature;

[0053] Figure 7 The fluorescence spectra of the red-near infrared organic material based on triptycene bridging with structure A-2 obtained in Example 2 of the present invention at different concentrations;

[0054] Figure 8 The fluorescence spectrum of the red-near infrared organic material based on triptycene bridging and structure A-2 obtained in Example 2 of the present invention and its constituent components;

[0055] Fig. 9The performance diagram of the solution-processed OLED device doped in the CBP main body obtained in Example 2 of the present invention; wherein (a) is a voltage-brightness-current density curve; (b) is a brightness-power efficiency-external quantum efficiency curve; (c) is a normalized electroluminescence spectrum;

[0056] Fig.10 The performance diagram of the solution-processed OLED device obtained in Example 2 of the present invention and not doped in the CBP main body; wherein (a) is the voltage-brightness-current density curve; (b) is the brightness-power efficiency-external quantum efficiency curve; and (c) is the normalized electroluminescence spectrum. DETAILED DESCRIPTION

[0057] In order to further understand the present invention, the preferred embodiments of the present invention are described below in conjunction with the examples, but it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, rather than limiting the claims of the invention. All raw materials of the present invention are not particularly limited in their sources, and can be purchased on the market or prepared according to conventional methods well known to those skilled in the art.

[0058] Example 1

[0059] This embodiment provides a red-near infrared organic material based on triptycene bridging, the structure of which is shown in Formula A-1:

[0060]

[0061] The synthetic route is as follows:

[0062]

[0063] The specific steps include:

[0064] S1: Under nitrogen protection, add 2-bromoanthracene (5.14 g, 20.0 mmol) to a 250.0 mL three-necked round-bottom flask with a magnetic stirrer, draw 45.0 mL of dichloroethane with a 50.0 mL syringe and inject it into the three-necked round-bottom flask, and stir at an oil bath temperature of 80°C until it melts; dissolve 2-amino-5-iodobenzoic acid (10.52 g, 40.0 mmol) in 50.0 mL of tetrahydrofuran, and add the resulting 2-amino-5-iodobenzoic acid solution to a constant pressure separatory funnel; dissolve isoamyl nitrite (6.8 mL, 100.0 mmol) in 45.0 mL of dichloroethane, and the resulting isoamyl nitrite solution Add another constant pressure separatory funnel; place the two constant pressure separatory funnels on the left and right mouths of the three-necked flask respectively, and control the dripping speed of the isoamyl nitrite solution to be slightly faster than that of the 2-amino-5-iodobenzoic acid solution; stir overnight at an oil bath temperature of 80°C; use a thin layer chromatography spot plate to detect the reaction end point, cool to room temperature, use a separatory funnel to extract to obtain a crude purified product, then use a rotary evaporator to dry, and then use petroleum ether as an eluent, purify by silica gel column chromatography, recrystallize with a mixed solution of dichloromethane and n-hexane, filter and dry to obtain a pure white powdery solid (2.75 g), i.e., intermediate compound T1, with a yield of 30%.

[0065] S2: Under nitrogen protection, the intermediate compound T1 (459.0 mg, 1.0 mmol), phenoxazine (220.0 mg, 1.2 mmol), cuprous iodide (190.0 mg, 0.1 mmol), potassium carbonate (410.0 mg, 3.0 mmol) and 18-crown-6 (264.0 mg, 0.1 mmol) were added to a 100.0 mL two-necked round-bottom flask with a magnetic stirrer, and the nitrogen was replaced three times. 220.0 mL of o-dichlorobenzene was injected into the reaction mixture, and the mixture was refluxed at an oil bath temperature of 180° C. for 24 hours; the reaction endpoint was detected by thin layer chromatography. After cooling to room temperature, the o-dichlorobenzene was removed by an oil pump, and then a mixed solution of n-hexane and dichloromethane was used as an eluent, and the mixture was purified by silica gel column chromatography, and recrystallized by a mixed solution of dichloromethane and n-hexane. After suction filtration and drying, a pure white powdery solid (436.0 mg) was obtained, namely, intermediate compound T2, with a yield of 85%.

[0066] S3: Under nitrogen protection, the intermediate compound T2 (514.0 mg, 1.0 mmol), diboronic acid pinacol ester (303.0 mg, 1.2 mmol), potassium acetate (294.0 mg, 3.0 mmol) and [1,1-bis(diphenylphosphino)ferrocene] palladium dichloride (72.0 mg, 0.1 mmol) were added in sequence into a 100 mL two-necked round-bottom flask with a magnetic stirrer, nitrogen was replaced three times, and then 30 mL of 1,4- Dioxane was reacted at an oil bath temperature of 110°C overnight; the reaction endpoint was detected by thin layer chromatography, and after cooling to room temperature, a crude purified product was extracted, which was then dried using a rotary evaporator, and then purified by silica gel column chromatography using a mixed solution of n-hexane and dichloromethane as an eluent, and recrystallized using a mixed solution of dichloromethane and n-hexane. After suction filtration and drying, a pure yellow powdery solid (476.0 mg) was obtained, i.e., intermediate compound T3, with a yield of 85%.

[0067] S4: Under nitrogen protection, 1,10-phenanthroline-5,6-dione (210.0 mg, 1.0 mmol) and 4-bromo-o-phenylenediamine (187.0 mg, 1.0 mmol) were added to a 50 mL two-necked round-bottom flask with a magnetic stirrer, the nitrogen was replaced three times, and then 20 mL of glacial acetic acid was injected, and the reaction was carried out at an oil bath temperature of 110°C overnight; the reaction end point was detected by thin layer chromatography, and after cooling to room temperature, the crude purified product was extracted, and then dried using a rotary evaporator, and then purified by silica gel column chromatography using a mixed solution of dichloromethane and ethyl acetate as an eluent, and recrystallized using a mixed solution of dichloromethane and methanol. After filtration and drying, a pure brown powder solid (310.0 mg), i.e., intermediate compound T4, was obtained with a yield of 85%.

[0068] S5: The intermediate compound T3 (561.0 mg, 1.0 mmol), the intermediate compound T4 (361.0 mg, 1.0 mmol), potassium acetate (294.0 mg, 3.0 mmol) and [1,1-bis(diphenylphosphino)ferrocene]palladium dichloride (72.0 mg, 0.1 mmol) were added in sequence into a 100.0 mL two-necked round-bottom flask with a magnetic stirrer, nitrogen was replaced three times, and then 30.0 mL of 1,4-Dioxane was reacted at an oil bath temperature of 100°C overnight; the reaction endpoint was detected by thin layer chromatography, and the crude purified product was extracted after cooling to room temperature, and then dried using a rotary evaporator. The product was then purified by silica gel column chromatography using a mixed solution of n-hexane and dichloromethane as an eluent, and recrystallized using a mixed solution of dichloromethane and methanol. After suction filtration and drying, an orange-yellow powdery solid (608.0 mg) was obtained, i.e., a triptycene-bridged red-near infrared organic material with a structure of A-1, with a yield of 85%.

[0069] The red-near infrared organic material based on triptycene bridging of structure A-1 synthesized in this example was tested by nuclear magnetic resonance spectroscopy, and the results were as follows:

[0070] 1 H NMR(600MHz,Chloroform-d)δ9.60(ddt,J=7.8,5.4,2.8Hz,2H),9.26(d,J=4.5Hz,2H),8.45(dd,J=7.5,2 .0Hz,1H),8.31(dd,J=8.8,4.5Hz,1H),8.13(ddd,J=8.9,6.9,2.0Hz,1H),7.91(dd,J=22.9,1.8Hz,1H),7 .77(dq,J=8.0,4.5,3.2Hz,2H),7.63–7.44(m,5H),7.38(dd,J=6.6,1.9Hz,1H),7.08(ddd,J=6.0,3.5,1. 6Hz, 2H), 6.99 (dd, J=7.7, 2.0Hz, 1H), 6.64–6.44 (m, 5H), 5.82 (dd, J=8.0, 1.4Hz, 2H), 5.66–5.40 (m, 3H).

[0071] The triptycene-bridged red-near infrared organic material of structure A-1 synthesized in this example, and its constituent components 10-([1,1':3',1'-triphenyl]-5'-yl)-10H-phenoxazine (denoted as TPh-PXZ) and dibenzo[a,c]phenazine (denoted as DPPZ) were dissolved in toluene solution to prepare 10 -5 The mixed solution of M was tested by ultraviolet fluorescence spectrum, and the results were as follows Figure 1 As shown, compared with the absorption peaks of the constituent components TPh-PXZ and DPPZ, the red-near infrared organic material based on triptycene bridging with structure A-1 does not present a new absorption peak, indicating that no new excited state transition is formed.

[0072] The red-near infrared organic material based on triptycene bridge of structure A-1 synthesized in this example was dissolved in a toluene solution to prepare mixed solutions of different concentrations, the concentrations of which were 10 -5 , 10 -4 , 10 -3 M, its fluorescence spectrum test results are as follows Figure 2 As shown, the red-near infrared organic material based on triptycene bridge with structure A-1 can be seen in 10 -5 M toluene solution showed a main emission peak at 436 nm and a shoulder peak at 560 nm. -4Under the M condition, a main emission peak of 521nm and a shoulder peak of 430nm were exhibited, indicating that with the increase in the concentration of the red-near infrared organic material based on triptycene bridging with structure A-1, its main emission peak at 521nm became stronger and the shoulder peak at 430nm gradually weakened.

[0073] The red-near infrared organic material based on triptycene bridge of structure A-1 synthesized in this example, its constituent components TPh-PXZ, DPPZ, and the mixture of TPh-PXZ and DPPZ, were dissolved in dichloromethane solution, and prepared into thin films. The film emission spectra of the red-near infrared organic material based on triptycene bridge of structure A-1 and its components and mixture were tested at room temperature. The results are as follows: Figure 3 As shown, the emission peak of TPh-PXZ is at 432nm, the emission peak of DPPZ is at 454nm, the emission peak of the red-near infrared organic material based on triptycene bridging with structure A-1 is at 630nm, and the emission peak of the mixture of TPh-PXZ and DPPZ is at 608nm, indicating that the red-near infrared organic material based on triptycene bridging with structure A-1 does not undergo intramolecular charge transfer, but has obvious intermolecular charge transfer emission peaks, and thus has the properties of a single molecule excited complex.

[0074] In addition, this embodiment also prepares a solution-processed organic electroluminescent device based on a red-near-infrared organic material based on triptycene bridging with structure A-1, including an ITO conductive substrate, a 40nm thick PEDOT:PSS hole transport layer, a 60nm thick light-emitting layer, a 60nm thick TmPyPb electron transport layer, a 1nm thick LiF electron injection layer and a 100nm thick Al cathode electrode arranged in sequence from bottom to top; wherein the light-emitting layer is composed of a red-near-infrared organic material based on triptycene bridging with structure A-1 doped in a main material, the doping concentration is 15wt%, and the main material is 4,4'-di(9-carbazole)biphenyl (CBP).

[0075] The preparation process of the solution-based organic electroluminescent device is as follows:

[0076] Q1: Pretreatment of ITO conductive substrate:

[0077] A substrate with a size of 32 mm×32 mm and a striped indium tin oxide (ITO) film pattern transparent electrode is selected as an ITO conductive substrate;

[0078] The ITO conductive substrate was sequentially placed in a cleaning agent, deionized water, acetone, and anhydrous ethanol, each of which was ultrasonicated for 30 minutes, and then the residual solvent on the surface was blown off with a nitrogen gun and ultraviolet treatment was performed with an ultraviolet ozone instrument for 15 minutes;

[0079] Q2: Preparation of the solution-based organic electroluminescent device:

[0080] On the surface of the pretreated ITO conductive substrate, a hole transport material solution was spin-coated at a speed of 3000 rpm for 40 seconds to obtain a PEDOT:PSS hole transport layer with a film thickness of 40 nm;

[0081] Then, the ITO conductive substrate was transferred to a glove box, and the luminescent material solution was spin-coated at a speed of 1700 rpm for 60 seconds using a spin coater to obtain a luminescent layer with a thickness of 60 nm. The luminescent material solution was prepared by doping a red-near infrared organic material A-1 based on triptycene bridge with a doping concentration of 15 wt% in CBP;

[0082] Place the ITO conductive substrate with the light-emitting layer into the slot of the evaporation instrument cavity and start to evacuate to 5×10 -4 Pa;

[0083] According to the pre-designed device structure, the electron transport material is heated by resistance heating. Vacuum evaporation was performed at a deposition rate of , and a 60nm thick TmPyPb electron transport layer was formed; then, a 100nm thick Al cathode was formed by evaporation using a metal mask orthogonal to the ITO stripes, and 1nm lithium fluoride was used as an electron injection layer, and finally a solution-processed organic electroluminescent device was prepared;

[0084] Q3: The prepared solution-process organic electroluminescent device is sealed and stored in a glove box filled with nitrogen with a water oxygen concentration below 0.5 ppm, and then the prepared light-emitting device is encapsulated with a glass sealing cover containing epoxy-type ultraviolet-curing resin and sealed with UV 365nm ultraviolet curing.

[0085] As a comparison, this embodiment also prepares a solution-processed organic electroluminescent device in which the red-near-infrared organic material A-1 based on triptycene bridging is not doped in the CBP main body. The preparation process is different from the above process in that the light-emitting layer is not doped with the red-near-infrared organic material A-1 based on triptycene bridging. The other structures and steps remain unchanged.

[0086] A direct current was applied to the prepared solution-processed organic electroluminescent device based on the triptycene-bridged red-near-infrared organic material with structure A-1 using a Keithley 2400 digital source meter, and the luminescence performance was evaluated using a Spectrascan PR655 luminance meter; the current-voltage characteristics were measured using a Keithley 2400 digital source meter, and the device performance was determined when the applied DC voltage changed.

[0087] Figure 4: is the performance diagram of the solution-processed OLED device (denoted as CBP:A-1) doped in the CBP main body obtained in this example, wherein: Figure 4 (a) is the voltage-brightness-current density curve, Figure 4 (b) is the brightness-power efficiency-external quantum efficiency curve, Figure 4 (c) is the normalized electroluminescence spectrum; Figure 5 : is the performance diagram of the solution-processed OLED device (denoted as A-1) obtained in this example without being doped in the CBP main body, wherein: Figure 5 (a) is the voltage-brightness-current density curve, Figure 5 (b) is the brightness-power efficiency-external quantum efficiency curve, Figure 5 (c) is the normalized electroluminescence spectrum. The performance data shown in Table 1 are obtained by statistics, and it can be seen that the solution-processed organic electroluminescent device doped in the CBP main body has a more excellent luminescence performance.

[0088] Table 1

[0089]

[0090]

[0091] Example 2

[0092] This embodiment provides a red-near infrared organic material based on triptycene bridging, the structure of which is shown in Formula A-2:

[0093]

[0094] The synthetic route is as follows:

[0095]

[0096] The specific steps include:

[0097] S1: The intermediate compound M1 was synthesized according to the process of step S1 in Example 1.

[0098] S2: Under nitrogen protection, the intermediate compound M1 (459.0 mg, 1.0 mmol), phenothiazine (240.0 mg, 1.2 mmol), cuprous iodide (190.0 mg, 0.1 mmol), potassium carbonate (410.0 mg, 3.0 mmol) and 18-crown-6 (264.0 mg, 0.1 mmol) were added to a 100.0 mL two-necked round-bottom flask with a magnetic stirrer, and the nitrogen was replaced three times. 220.0 mL of o-dichlorobenzene was injected into the reaction mixture, and the mixture was refluxed at an oil bath temperature of 180° C. for 24 hours; the reaction endpoint was detected by thin layer chromatography. After cooling to room temperature, the o-dichlorobenzene was removed by an oil pump, and then a mixed solution of n-hexane and dichloromethane was used as an eluent, and the mixture was purified by silica gel column chromatography, and recrystallized by a mixed solution of dichloromethane and n-hexane. After suction filtration and drying, a pure white powdery solid (436.0 mg) was obtained, namely, the intermediate compound M2, with a yield of 82%.

[0099] S3: The intermediate compound M3 was synthesized according to the process of step S3 in Example 1, specifically a yellow powdery solid (432.9 mg), with a yield of 75%.

[0100] S4: The intermediate compound M4 was synthesized according to the process of step S4 in Example 1.

[0101] S5: According to the process of step S5 in Example 1, a triptycene-bridged red-near infrared organic material with structure A-2 was synthesized, specifically an orange-yellow powdery solid (511.8 mg), with a yield of 70%.

[0102] The red-near infrared organic material based on triptycene bridging of structure A-2 synthesized in this example was tested by nuclear magnetic resonance spectroscopy, and the results were as follows:

[0103] 1 H NMR(600MHz,Chloroform-d)δ9.58(d,J=7.9Hz,2H),9.24(s,2H),8.47–8.37(m,1H),8.2 8(dt,J=9.8,5.0Hz,2H),8.15–8.07(m,1H),8.04(d,J=7.7Hz,1H),7.98–7.82(m,2H),7.7 4(d,J=8.1Hz,2H),7.62–7.36(m,5H),7.32–7.22(m,1H),7.06(dtt,J=18.5,12.2,6.7Hz ,3H),6.91(q,J=4.0,3.6Hz,1H),6.66(d,J=49.9Hz,2H),6.09(s,1H),5.72–5.33(m,3H).

[0104] The triptycene-bridged red-near infrared organic material A-2 synthesized in this example, and its constituent components 10-([1,1':3',1'-triphenyl]-5'-yl)-10H-phenothiazine (denoted as TPh-PTZ) and dibenzo[a,c]phenazine (denoted as DPPZ) were dissolved in toluene solution to prepare 10 -5 The mixed solution of M was tested by ultraviolet fluorescence spectrum, and the results were as follows Figure 6 As shown, compared with the absorption peaks of the constituent components TPh-PTZ and DPPZ, the red-near infrared organic material based on triptycene bridging with structure A-2 does not present a new absorption peak, indicating that no new excited state transition is formed.

[0105] The red-near infrared organic material based on triptycene bridge of structure A-2 synthesized in this example was dissolved in a toluene solution to prepare mixed solutions of different concentrations, the concentrations of which were 10 -5 , 10 -4 , 10 -3 M, its fluorescence spectrum test results are as follows Figure 7 As shown, it can be seen that the red-near infrared organic material based on triptycene bridge with structure A-2 has a high -5 M toluene solution showed a main emission peak at 443 nm and a shoulder peak at 513 nm. -4 Under the M condition, a main emission peak of 516 nm and a shoulder peak of 456 nm were exhibited; with the increase of the concentration of the red-near infrared organic material based on triptycene bridging with structure A-2, it only exhibited a main emission peak of 521 nm.

[0106] The red-near infrared organic material based on triptycene bridge structure A-2 synthesized in this example, its constituent components TPh-PTZ, DPPZ, and the mixture of TPh-PTZ and DPPZ, were dissolved in dichloromethane solution and prepared into thin films. The film emission spectra of the red-near infrared organic material based on triptycene bridge structure A-2 and its components and mixture were tested at room temperature. The results are as follows: Figure 8 As shown, the emission peak of TPh-PTZ is at 459nm, the emission peak of DPPZ is at 454nm, the emission peak of the red-near infrared organic material based on triptycene bridging with structure A-2 is at 638nm, and the emission peak of the mixture of TPh-PTZ and DPPZ is at 616nm, indicating that the red-near infrared organic material based on triptycene bridging with structure A-2 does not undergo intramolecular charge transfer, but has obvious intermolecular charge transfer emission peaks, and thus has the properties of a single molecule excited complex.

[0107] In this embodiment, a solution-processed organic electroluminescent device based on a red-near-infrared organic material based on triptycene bridging with structure A-2 was prepared according to the method of embodiment 1. Except for the light-emitting layer, the other structures were exactly the same. The light-emitting layer was composed of a red-near-infrared organic material based on triptycene bridging with structure A-2 doped in a host material, with a doping concentration of 15wt%, and the host material was 4,4'-bis(9-carbazole)biphenyl (CBP).

[0108] As a comparison, this embodiment also prepares a solution-processed organic electroluminescent device in which the red-near-infrared organic material A-2 based on triptycene bridging is not doped in the CBP main body. The preparation process is different from the above process in that the light-emitting layer is not doped with the red-near-infrared organic material A-2 based on triptycene bridging. The other structures and steps remain unchanged.

[0109] Fig. 9 : is the performance diagram of the solution-processed OLED device doped in the CBP main body (denoted as CBP:A-2) obtained in this example, wherein: Fig. 9 (a) is the voltage-brightness-current density curve, Fig. 9 (b) is the brightness-power efficiency-external quantum efficiency curve, Fig. 9 (c) is the normalized electroluminescence spectrum; Fig.10 : is the performance diagram of the solution-processed OLED device (denoted as A-2) obtained in this example without being doped in the CBP main body, wherein: Fig.10 (a) is the voltage-brightness-current density curve, Fig.10 (b) is the brightness-power efficiency-external quantum efficiency curve, Fig.10 (c) is the normalized electroluminescence spectrum. The performance data shown in Table 2 are obtained by statistics, and it can be seen that the solution-processed organic electroluminescent device doped in the CBP main body has a more excellent luminescence performance.

[0110] Table 2

[0111]

[0112] In summary, the red-near infrared organic material based on triptycene bridging provided in this embodiment has the characteristics of short delayed fluorescence lifetime and high photoluminescence quantum efficiency, and is particularly suitable for solution-processed OLED devices, and can achieve excellent electroluminescent performance.

[0113] The present invention uses specific examples to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core ideas, including the best mode, and also enables any technician in the field to practice the present invention, including making and using any device or system, and implementing any combined method. It should be pointed out that for ordinary technicians in this technical field, without departing from the principle of the present invention, the present invention can also be improved and modified, and these improvements and modifications also fall within the scope of protection of the claims of the present invention. The scope of patent protection of the present invention is defined by the claims and may include other embodiments that can be thought of by those skilled in the art. If these other embodiments have structural elements that are not different from the text of the claims, or if they include equivalent structural elements that are not substantially different from the text of the claims, then these other embodiments should also be included in the scope of the claims. Some other embodiments should also be included in the scope of the claims.

Claims

1. A red-near infrared organic material based on triptycene bridging, characterized in that: Its structure is shown in formula (I): Wherein, R1 is selected from phenoxazine, phenothiazine, phenoxazine derivatives, phenothiazine derivatives, and substituted heteroaryl.

2. The red-near infrared organic material based on triptycene bridging according to claim 1, characterized in that: The substituted heteroaryl group is specifically a structure of the following formula (II) to formula (X):

3. A method for preparing a red-near infrared organic material based on triptycene bridging, characterized in that: The following steps are involved: Step 1: Performing a ring-closing reaction on 2-bromoanthracene and a 2-amino-5-iodobenzoic acid derivative to obtain an intermediate compound C1; Step 2, the intermediate compound C1 and the donor group derivative substituent R1 undergo a carbon-carbon coupling reaction under the action of a first catalyst to obtain an intermediate compound C2; Step 3, performing ester substitution on the intermediate compound C2 to obtain the intermediate compound C3 through esterification reaction; Step 4: Carry out carbonyl protection reaction based on phenanthrene-9,10-dione and 4-bromobenzene-1,2-diamine to prepare intermediate compound C4; Step 5: The intermediate compounds C3 and C4 react under the action of a second catalyst to obtain the red-near infrared organic material based on triptycene bridging. Among them, the intermediate compounds C1, C2, C3 and C4 are specifically materials of the following structural formula:

4. The method for preparing the red-near infrared organic material based on triptycene bridging according to claim 3, characterized in that: The specific process of step 1 is: Under nitrogen protection, a 2-bromoanthracene solution is added to a three-necked flask with a stirring magnet, and the temperature is raised to 80-110° C. to dissolve the 2-bromoanthracene; at the same time, a 2-amino-5-iodobenzoic acid solution is added to one end of the three-necked flask, and an isoamyl nitrite solution is added to the other end, and the dripping speed of the isoamyl nitrite solution is controlled to be slightly faster than that of the 2-amino-5-iodobenzoic acid solution, and the reaction is maintained at 80-110° C.; after the reaction is completed, the intermediate compound C1 is obtained after sequentially crude purification, drying, purification, recrystallization, suction filtration and drying; wherein the molar ratio of 2-bromoanthracene to 2-amino-5-iodobenzoic acid and isoamyl nitrite is 1:2-3:5-8.

5. The method for preparing the red-near infrared organic material based on triptycene bridging according to claim 3, characterized in that: The specific process of step 2 is: Under nitrogen protection, an intermediate compound C1, a donor group derivative substituent R1, a carbonate, and a first reaction catalyst are added in sequence to a double-necked bottle with a stirring magnet in a molar ratio of 1:1.1-2:3-5:0.1-0.

3. After nitrogen is replaced several times, the first organic solvent is injected, and the obtained first mixed solution is refluxed at an oil bath temperature of 180-220°C for 18-36h. After that, the first organic solvent is removed by an oil pump, and after purification, recrystallization, filtration and drying in sequence, an intermediate compound C2 is obtained; wherein, the concentration of the intermediate compound C1 in the first mixed solution is not less than 0.0045mol / L.

6. The method for preparing the red-near infrared organic material based on triptycene bridging according to claim 3, characterized in that: The specific process of step 3 is: Under nitrogen protection, an intermediate compound C2, bipyraclostrobin, acetate and a palladium catalyst are added in sequence to a double-necked bottle with a stirring magnet in a molar ratio of 1:1 to 1.5:3 to 5:0.1 to 0.3, and a second organic solvent is injected. The obtained second mixed solution is reacted at 80 to 110° C. After the reaction is completed, the intermediate compound C3 is obtained after sequential crude purification, drying, purification, recrystallization, suction filtration and drying; wherein the concentration of the intermediate compound C3 in the second mixed solution is not less than 0.033 mol / L.

7. The method for preparing the red-near infrared organic material based on triptycene bridging according to claim 3, characterized in that: The specific process of step 4 is: Under nitrogen protection, 1,10-phenanthroline-5,6-dione and 4-bromo-o-phenylenediamine are added in sequence in a double-necked bottle with a stirring magnet in a molar ratio of 1:1 to 3, and glacial acetic acid is injected. The obtained third mixed solution is reacted at 100 to 130° C. After the reaction is completed, the intermediate compound C4 is obtained after sequential crude purification, drying, purification, recrystallization, suction filtration and drying; wherein the concentration of the intermediate compound C4 in the third mixed solution is not less than 0.05 mol / L.

8. The method for preparing the red-near infrared organic material based on triptycene bridging according to claim 3, characterized in that: The specific process of step 5 is: Under nitrogen protection, an intermediate compound C3, an intermediate compound C4, acetate and a palladium catalyst are added in sequence into a double-necked bottle with a stirring magnet, and the molar ratio thereof is 1:1-1.5:3-5:0.1-0.3, and a third organic solvent is injected. The resulting fourth mixed solution is reacted at 80-110° C. After the reaction is completed, the red-near infrared organic material based on triptycene bridging is purified; wherein the concentration of the intermediate compound C3 in the fourth mixed solution is 0.033 mol / L.

9. Use of the red-near infrared organic material based on triptycene bridge obtained according to the preparation method according to any one of claims 3 to 8 in a solution-processed organic electroluminescent device.

10. A solution-processed organic electroluminescent device, characterized in that: It comprises an anode, a hole transport layer, a light-emitting layer, an electron transport layer and a cathode stacked in sequence; wherein the light-emitting layer is composed of a red-light-near infrared organic material based on triptycene bridging obtained by the preparation method according to any one of claims 3 to 8 doped in a main material.

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