TADF polymer material as well as preparation method and application thereof

Abstract

The invention relates to a thermally activated delayed fluorescence (TADF) polymer material and a preparation method thereof.The preparation method comprises the steps that firstly, a non-conjugated polymer main chain PDFC-N3 is synthesized through a Suzuki condensation polymerization reaction and azidation treatment of a 3, 6-dibromo carbazole monomer (3, 6-CzBr) and bis-ether fluorene (DF-BO) with a flexible hexyl chain, and then the polymer main chain PDFC-N3 is synthesized through an azide reaction; then, a TADF red light unit TB and a TADF blue light unit DT in different proportions are hooked to the main chain through azide-alkynyl click reaction to realize post-functionalization, and the polymer is in double-peak emission. The polymer disclosed by the invention is relatively high in molecular weight, excellent in solution processability and relatively good in thermal stability, and when the molar ratio of a blue light unit to a red light unit hooked on a main chain of the polymer is 97: 3-90: 10, the polymer serving as a luminescent layer material realizes white light emission in a prepared non-doped organic electroluminescent device.

Description

Technical Field

[0001] The present invention relates to the field of organic light-emitting materials, and in particular to a TADF polymer material and a preparation method and application thereof. Background Art

[0002] Organic Light-Emitting Diodes (OLEDs) have low cost, excellent color rendering, a wide range of applications, and broad development prospects. Thermally Activated Delayed Fluorescence (TADF) materials, as the third generation of organic light-emitting materials after traditional fluorescent materials and phosphorescent materials, can use singlet excitons to directly transition back to the ground state to radiate and emit light to complete the transient fluorescence process. In addition, because the energy difference between its singlet excitons and triplet excitons is very small, under low ambient heat, they can be converted to a singlet state through the reverse intersystem crossing (RISC) process of triplet excitons and then radiate to the ground state to emit delayed fluorescence. Therefore, TADF materials can achieve a theoretical internal quantum efficiency of 100%, which has broad prospects and industrial value.

[0003] With technological advancements, the need for high-quality displays and lighting has driven the development of white organic light-emitting diodes (WOLEDs). WOLED luminescent materials have gradually transitioned from traditional fluorescent and phosphorescent materials to TADF materials or hybrid luminescent materials. White light emission is achieved through incomplete energy transfer from short-wavelength (blue) luminescent materials to long-wavelength (yellow, orange, or red) luminescent materials or phosphorescent materials. Due to this incomplete energy transfer, the concentration of short-wavelength (blue) molecules in the complementary white system must significantly exceed that of long-wavelength (yellow, orange, or red) molecules. Currently, TADF luminescent materials used in WOLEDs primarily include small molecules, polymers, and dendrimers. However, small molecule materials often undergo recrystallization and phase separation, resulting in high film roughness and fragile luminescent layer surfaces, hindering the solution-processed preparation of stable and efficient WOLEDs. Furthermore, some existing multi-luminescent layer devices, which generate white light by mixing complementary colors, suffer from low color rendering index, device efficiency degradation, and unstable color coordinates. Therefore, selecting high-molecular-weight polymers as luminescent layer materials is the best approach to achieving excellent solubility and morphological stability, ultimately resulting in solution-processable WOLEDs.

[0004] CN 113527268 A discloses a compound containing a biscarbazole and triazine structure and an organic electroluminescent device. These compounds are used in organic electroluminescent devices. Deuteration is introduced into the carbazole and biphenyl groups between the carbazole and triazine structures. This effectively adjusts the HOMO energy level of the material molecule, improving its compatibility with adjacent functional layers and further increasing the triplet energy level of the material molecule, thereby effectively improving the luminous efficiency and lifespan of the device. At the same current density, the luminous efficiency is significantly improved, the device's startup voltage is reduced, and the device's power consumption is relatively reduced, resulting in a corresponding increase in the device's lifespan.

[0005] CN 117143591 A discloses a white-light luminescent material, its preparation method, and application. The material comprises a bridging unit Ar and different luminescent units, each connected by the bridging unit Ar. The white-light luminescent material is constructed by embedding TADF luminescent units of different light colors into a polymer backbone, designing different types of TADF units and bridging units, and utilizing a simple synthesis method for mass production. The material exhibits good solubility and film-forming properties, is suitable for solution processing, and has a broad luminescence spectrum. Furthermore, the material exhibits excellent electroluminescent properties.

[0006] Existing TADF polymer white light materials have the following defects, namely the technical problems to be solved by the present invention are: first, the use of a physical mixture system of the host and the TADF polymer as the light-emitting layer inevitably produces phase separation, resulting in a decrease in device performance; second, the existing conjugated TADF white light polymer, the light-emitting unit is located on the main chain or side chain, and exhibits enhanced charge transport and device performance due to the extended main chain conjugation, but is usually accompanied by reduced solubility and emission red shift due to the charge transfer effect. Summary of the Invention

[0007] In view of the shortcomings of the existing technology, the present invention solves two technical problems. First, a single polymer PDFC-DT is used. x -TB y As a single light-emitting layer to solve the problem of phase separation on the film surface; secondly, a non-conjugated polymer backbone was designed and synthesized by Suzuki polymerization, in which the hole-transporting spacer units - carbazole and bis(ether)fluorene - were embedded in the alkyl chain.

[0008] The purpose of the present invention is to provide a TADF polymer material, and providing a preparation method and application thereof is another purpose of the present invention. When the molar ratio of the blue light unit to the red light unit attached to the polymer main chain is 97:3-90:10, the polymer of the present invention can achieve white light emission. Compared with the TADF small molecule white light material, this white light material can not only retain the high-efficiency luminescence characteristics of the TADF material, but also inhibit the crystallization tendency of the molecule, improve the thermal stability and solution processing performance of the light-emitting layer material, and has the potential to develop efficient and stable solution-processable WOLED.

[0009] In order to achieve the above-mentioned object of the invention, the present invention adopts the following technical solutions:

[0010] A TADF polymer white light material, the white light material is PDFC-DT x -TB y , whose chemical structure is shown in formula (1):

[0011]

[0012] Among them, R1- is a blue light functional compound group, and the blue light functional compound is a biscarbazolyl-triazine compound; R2- is a red light functional compound group, and the red light functional compound is a triphenylamine-anthraquinone compound.

[0013] Preferably, the biscarbazolyl-triazine compound is The triphenylamine-anthraquinone compound is In addition, x and y on the polymer main chain respectively represent the molar numbers of the blue light unit and the red light unit attached to the polymer main chain, and the value range of x:y is 97:3-90:10.

[0014] The present invention also discloses a method for preparing a TADF polymer material, comprising the following steps:

[0015] 1) Preparation of polymer backbone PDFC-N3

[0016]

[0017] 2) Preparation of blue light functional compound DT-Alk

[0018]

[0019] 3) Preparation of red light functional compound TB-Alk

[0020]

[0021] 4) Synthesis of PDFC-DT x -TB y

[0022]

[0023] Compared with the prior art, the positive effects of the present invention are: TADF polymers with higher molecular weight can be obtained relatively easily, and the reproducibility of each batch of material preparation is good; TADF red light units and TADF blue light units are sequentially introduced into the side chains of the polymer, and white light with dual emission peaks is obtained through incomplete energy transfer between the light-emitting units; a "post-functionalization" method is adopted to control the luminescent color of the polymer by regulating the molar ratio of the TADF blue light functional compound and the TADF red light functional compound in the polymer, thereby achieving white light emission; a non-conjugated polymer main chain poly(carbazole-hexane-bisetherfluorene) is synthesized to have modified groups and good solubility for facilitating the synthesis of TADF polymers; and it has good film-forming properties and high thermal stability.

[0024] Based on the advantages described above, OLED devices can be produced using a solution processing process. Compared to traditional vacuum evaporation processes, this method is simpler to prepare, enabling large-scale production of OLED devices and reducing industrial production costs. This method, using the polymer of the present invention as the light-emitting layer material in the production of OLED devices, can achieve excellent device performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 Schematic diagram of the device structure for application of the compound of the present invention;

[0026] Figure 2 The monomer 3,6-CzBr in CDCl3 1 H NMR spectrum;

[0027] Figure 3 The intermediate DF-Br in CDCl3 1 H NMR spectrum;

[0028] Figure 4 The monomer DF-BO in CDCl3 1 H NMR spectrum;

[0029] Figure 5 The main chains of polymer PDFC-Br and PDFC-N3 in CDCl3 1 H NMR spectrum;

[0030] Figure 6 The intermediate Trz-OCH3 in CDCl3 1 H NMR spectrum;

[0031] Figure 7 The intermediate mCP-Br in CDCl3 1 H NMR spectrum;

[0032] Figure 8 The intermediate mCP-BO in CDCl3 1 H NMR spectrum;

[0033] Figure 9 The intermediate DCzTrz-OCH3 in CDCl3 1 H NMR spectrum;

[0034] Figure 10 The intermediate DCzTrz-OH in DMSO 1 H NMR spectrum;

[0035] Figure 11 The functional compound DT-Alk in CDCl3 1 H NMR spectrum;

[0036] Figure 12 The intermediate TPA-OCH3 in CDCl3 1 H NMR spectrum;

[0037] Figure 13 The intermediate TPABO-OCH3 in CDCl3 1 H NMR spectrum;

[0038] Figure 14 The intermediate TB-OCH3 in CDCl3 1 H NMR spectrum;

[0039] Figure 15 The intermediate TB-OH in DMSO 1 H NMR spectrum;

[0040] Figure 16 The functional compound TB-Alk in CDCl3 1 H NMR spectrum;

[0041] Figure 17 Functional compound DT-Alk, functional compound TB-Alk, polymer backbone PDFC-N3 and target polymer PDFC-DT 85 -TB 15 In CDCl3 1 H NMR spectrum;

[0042] Figure 18 TADF polymer PDFC-DT x -TB y In CDCl3 1 H NMR spectrum;

[0043] Figure 19 Based on PDFC-DT x -TB y EL spectrum of non-doped OLED device;

[0044] Figure 20 Based on PDFC-DT x -TB y CIE coordinate diagram of non-doped OLED device at maximum brightness;

[0045] Figure 21 TADF polymer PDFC-DT 97 -AFM images of TB3 thin films;

[0046] Figure 22 TADF polymer PDFC-DT x -TB y TG and DSC curves of (x=1, 3, 5, 10, 15). DETAILED DESCRIPTION

[0047] The principles and features of the present invention are described below. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0048] Example 1

[0049] TADF polymer material PDFC-DT x -TB y , prepared by the following steps:

[0050] 1. Synthesis of polymer backbone PDFC-N3

[0051] 1) Synthesis of monomer 3,6-CzBr

[0052]

[0053] 3,6-Dibromocarbazole (3.254 g, 9 mmol) was placed in a 100 mL round-bottom flask and dissolved in 20 mL of tetrahydrofuran. Sodium hydride (0.528 g, 24 mmol) was slowly added. Bubbling was observed within the flask, and after stabilization, 1,6-dibromohexane (5.372 g, 22 mmol) was added. The reaction was allowed to proceed at 50°C for 12 h, and progress was monitored by thin-layer chromatography (TLC). After completion of the reaction, the system was cooled to room temperature, filtered, extracted with dichloromethane, and washed with saturated brine to remove impurities, yielding a yellow organic phase. Anhydrous magnesium sulfate was added, stirred for 10 h, filtered, and the solvent was evaporated under reduced pressure. The crude product was further purified by silica gel column chromatography (petroleum ether / dichloromethane = 5 / 1, v / v). The target compound was isolated by gradient elution to obtain 3,6-CzBr (3.249 g, 65% yield) as a white flocculent product. 1 H NMR (600MHz, CDCl3), δ8.16(s,2H),7.55(dd,2H),7.28(t,2H),4.26(t,2H),3.38(t,2H),1.91-1.78(m,4H),1.52-1.45(m,2H),1.40-1.32(m,2H). Such as Figure 2 shown.

[0054] 2) Synthesis of monomer DF-BO

[0055]

[0056] To a 50 mL round-bottom flask, bisphenol fluorene (1.051 g, 3 mmol), 1,6-dibromohexane (5.855 g, 24 mmol), and potassium carbonate (3.317 g, 24 mmol) were added and dissolved in 25 mL of acetone. The mixture was refluxed at 60°C for 24 h. After completion of the reaction, the reaction was processed as above. Finally, the crude product was further purified by silica gel column chromatography (petroleum ether / dichloromethane = 6 / 1, v / v). The target compound was isolated by gradient elution to obtain DF-Br (1.234 g, 61% yield) as a colorless oil. 1 H NMR(400MHz, CDCl3), δ7.64-7.68(d,2H),7.33-7.14(m,6H),7.00(d,2H),6.67-6.61(d,4H),3 .85-3.78(t,4H),3.39-3.25(t,4H),1.84-1.74(m,4H),1.70-1.62(m,4H),1.44-1.32(m,8H). Such as Figure 3 shown.

[0057] DF-Br (1.011 g, 1.52 mmol), 4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenol (2.641 g, 12 mmol), and cesium carbonate (3.310 g, 12 mmol) were added to a 50 mL round-bottom flask and dissolved in 20 mL of acetone. The mixture was refluxed at 60°C for 24 h. After completion of the reaction, the reaction was processed as above. Finally, the crude product was further purified by silica gel column chromatography (petroleum ether / ethyl acetate = 5 / 1, v / v) to obtain DF-BO (802 mg, 56% yield) as a white solid powder. 1 H NMR(400MHz, CDCl3), δ7.76-7.69(m,6H),7.74-7.29(m,4H),7.27-7.22(t,2H),7.10(d,4H),6.87( d,4H),6.73(d,4H),3.97(t,4H),3.89(t,4H),1.84-1.71(m,8H),1.55-1.44(m,8H),1.32(s,24H). Such as Figure 4 shown.

[0058] 3) Synthesis of polymer backbone PDFC-N3

[0059]

[0060] 3,6-CzBr (1.561 g, 3.3 mmol) and DF-BO (3.055 g, 3.3 mmol) were weighed and placed in a 25 mL Schlenk tube. The mixture was degassed three times with nitrogen. 30 mL of tetrahydrofuran, 1.5 mL of deionized water, cesium carbonate (6.847 g, 21.0 mmol), tetrabutylammonium bromide (228.80 mg, 0.71 mmol) and tetrakis(triphenylphosphine)palladium (Pd(Ph3)4(0), 463.10 mg, 0.40 mmol) were added and reacted at 60 ° C in the dark for 60 h. The end point of the polycondensation reaction was monitored by TLC. Subsequently, phenylboronic acid (121.60 mg, 1.01 mmol) and iodobenzene (208.20 mg, 1.02 mmol) were added and the end-capping reaction was carried out for 12 h respectively. After the reaction is complete, the mixture is cooled to room temperature, extracted with dichloromethane, and washed multiple times with saturated brine. The lower organic phase is collected. The product is then flash-chromatographed using ethyl acetate and dichloromethane, followed by vacuum concentration. A small amount of tetrahydrofuran is added to fully dissolve the product, which is then slowly added dropwise to rapidly stirred icy methanol to induce precipitation of the target polymer. After filtration, the solid powder is collected and Soxhlet extracted with methanol and acetone for three days each, yielding PDFC-Br (2.174 g, 64.1% yield) as a white solid. 1H NMR(400MHz, CDCl3), δ8.30(s,2H),7.75(d,2H),7.70-7.60(m,6H),7.45-7.31(m,6H),7.26(d,2H),7.15-7.08(d,4H),7.00(d ,4H),6.78-6.72(d,4H),4.33(s,2H),4.07-3.88(d,8H),3.38(t,2H),1.98-1.72(m,12H),1.60-1.41(m,12H).GPC(THF,PS):M n =1.59×10 4 ,PDI=1.58. Figure 5 shown.

[0061]

[0062] The polymer PDFC-Br (1.029 g, 1.00 mmol) was weighed and placed in a 50 mL round-bottom flask. Sodium azide (651.0 mg, 10.0 mmol) and tetrabutylammonium bromide (65.32 mg, 0.2 mmol) were then added. Then, 15 mL of tetrahydrofuran was added and stirred until the solution became clear. The reaction was incubated at 60°C in the dark for 48 hours. After completion, the reaction was cooled to room temperature, extracted with dichloromethane, and washed with deionized water. The lower organic phase was collected and concentrated under vacuum. A small amount of tetrahydrofuran was added to fully dissolve the polymer. The solution was then slowly added dropwise to rapidly stirred icy methanol to induce precipitation of the target polymer. The solid powder was collected by filtration and Soxhlet extraction with methanol and acetone for three days each, yielding PDFC-N3 (963.77 mg, 97% yield) as a white solid. 1 H NMR(400MHz, CDCl3), δ8.30(s,2H),7.75(d,2H),7.70-7.60(m,6H),7.45-7.31(m,6H),7.26(d,2H),7.15-7.08(d,4H),7.00(d, 4H),6.78-6.72(d,4H),4.33(s,2H),4.07-3.88(d,8H),3.19(t,2H),1.98-1.72(m,12H),1.60-1.41(m,12H).FT-IR(KBr),υ(cm -1 ):2093(-N3).GPC(THF,PS):M n =1.01×10 4 ,PDI=1.95. Figure 5 shown.

[0063] 2. Synthesis of blue light functional compound DT-Alk

[0064] 1) Synthesis of intermediate Trz-OCH3

[0065]

[0066] Weigh 2,4-dichloro-6-phenyl-1,3,5-triazine (2.249 g, 10 mmol) and 4-methoxyphenylboronic acid (1.596 g, 10 mmol) and place them in a 100 mL Schlenk bottle. Add 50 mL of purified tetrahydrofuran under nitrogen atmosphere and stir to dissolve. Prepare 15 mL of potassium carbonate (4.146 g, 30 mmol, 2 mol L -1 ) aqueous solution and added, followed by Pd(Ph3)4(0) (0.578 g, 0.51 mmol), stirred at room temperature for 10 minutes, transferred to an oil bath and heated to 60°C, and refluxed for 10 hours. After the reaction stopped and cooled to room temperature, it was extracted with dichloromethane and washed with saturated brine several times. The lower yellow organic phase was collected, and anhydrous magnesium sulfate was added and stirred for 10 hours. The solvent was removed by filtration under reduced pressure and vacuum concentration. The crude product was further purified by silica gel column chromatography (petroleum ether / dichloromethane = 2:1, v / v) to obtain Trz-OCH3 white powder (1.924 g, yield 65%). 1 H NMR (400MHz, CDCl3), δ8.65-8.53(m,4H),7.63-7.48(m,3H),7.04-6.99(m,2H),3.91(s,3H). Such as Figure 6 shown.

[0067] 2) Synthesis of intermediate mCP-Br

[0068]

[0069] 1,3,5-Tribromobenzene (3.148 g, 10.0 mmol), carbazole (3.678 g, 22.0 mmol), and potassium carbonate (5.520 g, 40 mmol) were weighed and added sequentially to a 100 mL Schlenk flask. 30 mL of N,N-dimethylformamide was added for dissolution. Under a nitrogen atmosphere, cuprous iodide (0.952 g, 5.0 mmol) and 1,10-phenanthroline (0.991 g, 5.0 mmol) were added. The mixture was then refluxed in an oil bath at 130°C for 48 h. After completion of the reaction, the mixture was cooled to room temperature, filtered under reduced pressure, extracted with dichloromethane, and washed several times with saturated brine. The dark organic phase was collected and concentrated under vacuum to remove the solvent. The mixture was further purified by silica gel column chromatography (petroleum ether / dichloromethane = 10:1, v / v) to afford mCP-Br (1.895 g, 39.1% yield) as a white solid powder. 1H NMR (400MHz, CDCl3), δ8.15(d,2H),7.85(d,2H),7.78(t,1H),7.58-7.42(t,8H),7.35-7.27(t,4H). Such as Figure 7 shown.

[0070] 3) Synthesis of intermediate mCP-BO

[0071]

[0072] mCP-Br (1.458 g, 3.0 mmol), potassium acetate (0.901 g, 9.3 mmol), and bis(pinacolato)diboron (3.373 g, 12.09 mmol) were added to a 100 mL Schlenk flask. 1,4-Dioxane (30 mL) was added and dissolved with stirring at room temperature. [1,1'-Bis(diphenylphosphino)ferrocene]palladium dichloride (150.37 mg, 0.18 mmol) was added under a nitrogen atmosphere. The mixture was heated to 100°C and refluxed for 24 h. After completion of the reaction, the mixture was cooled to room temperature, filtered under reduced pressure, extracted with dichloromethane, and washed with saturated brine. The dark organic phase was collected and the solvent was removed under vacuum. The crude product was further purified by silica gel column chromatography (petroleum ether / dichloromethane = 1:1, v / v) to obtain mCP-BO (1.170 g, 73% yield), a white solid powder. 1 H NMR (400MHz, CDCl3), δ8.15(d,2H),7.85(d,2H),7.78(t,1H),7.58-7.42(t,8H),7.35-7.27(t,4H),1.35(s,12H). Such as Figure 8 shown.

[0073] 4) Synthesis of intermediate DCzTrz-OCH3

[0074]

[0075] mCP-BO (1.068 g, 2.0 mmol), Trz-OCH3 (653.55 mg, 2.2 mmol) and tetrabutylammonium bromide (32.23 mg, 0.1 mmol) were weighed and added to a 100 mL Schlenk bottle, and 20 mL of tetrahydrofuran was added to dissolve. Pd(Ph3)4(0) (115.55 mg, 0.1 mmol) and 5 mL of potassium carbonate (1.382 g, 10.0 mmol, 2 mol L) were added under a nitrogen atmosphere. -1) aqueous solution and refluxed in a 60°C oil bath for 24 hours. After completion of the reaction, the mixture was cooled to room temperature, extracted with dichloromethane, and washed with saturated brine. The lower yellow organic phase was collected and concentrated in vacuo to remove the solvent. The crude product was purified by silica gel column chromatography (petroleum ether / ethyl acetate = 5:1, v / v) to obtain a yellow solid powder DCzTrz-OCH3 (1.017 g, 76.0% yield). 1 HNMR (400MHz, CDCl3), δ8.69-8.60(m,4H),8.19-8.14(d,4H),7.85(t,1H),7.75-7.53(m,9H),7.45-7.30(m,8H),7.04(d,2H),3.94(s,3H). Such as Figure 9 shown.

[0076] 5) Synthesis of intermediate DCzTrz-OH

[0077]

[0078] DCzTrz-OCH3 (1.017 g, 1.5 mmol) was added to a 50 mL round-bottom flask, and 20 mL of dichloromethane was added dropwise to dissolve the mixture. The mixture was stirred in an ice-water bath for 20 minutes, followed by the slow dropwise addition of boron tribromide (375 μL, 3.75 mmol) in an ice-water bath. The mixture was heated to 35°C and refluxed for 24 hours. After the reaction, ice water was slowly added dropwise in an ice-water bath to quench the residual boron tribromide. The mixture was extracted with ethyl acetate, washed with saturated brine, and the upper organic phase was collected and concentrated in vacuo to remove the solvent. The crude product was further purified by silica gel chromatography (petroleum ether / ethyl acetate = 3:1, v / v) to obtain DCzTrz-OH (815.77 mg, 83.1% yield) as a yellow solid powder. 1 H NMR(400MHz,DMSO),δ10.38(s,1H),8.97(d,2H),8.70-8.50(d,4H),8.30( d,4H),8.17(t,1H),7.69-7.45(m,11H),7.38-7.30(t,4H),6.93(d,2H). Such as Figure 10 shown.

[0079] 6) Synthesis of blue light functional compound DT-Alk

[0080]

[0081] DCzTrz-OH (786.28 mg, 1.2 mmol), potassium carbonate (497.55 mg, 3.6 mmol), and tetrabutylammonium bromide (19.34 mg, 0.06 mmol) were weighed and added to a 50 mL round-bottom flask. Acetone (15 mL) was then added, followed by the slow dropwise addition of propargyl bromide (860.16 mg, 7.2 mmol). The mixture was refluxed at 60°C for 24 h. After completion of the reaction, the mixture was cooled to room temperature, filtered under reduced pressure, extracted with dichloromethane, and washed with saturated brine. The lower organic phase was collected and the solvent was removed under vacuum. The crude product was purified on a silica gel column (petroleum ether / ethyl acetate = 5:1, v / v) to obtain DT-Alk (425.93 mg, 51.2% yield) as a yellow solid powder. 1 H NMR (400MHz, DMSO), δ9.07(d,2H),8.73-8.68(d,4H),8.20(d,4H),8.04(t,1H),7. 64-7.45(m,11H),7.38-7.32(t,4H),7.12-7.07(d,2H),4.77(d,2H),2.54(s,1H). Such as Figure 11 shown.

[0082] 3. Synthesis of red light functional compound TB-Alk

[0083] 1) Synthesis of intermediate TPA-OCH3

[0084]

[0085] 4-Bromodiphenylamine (1.488 g, 6.0 mmol), 4-iodoanisole (1.685 g, 7.2 mmol), and potassium hydroxide (3.029 g, 54.0 mmol) were weighed and placed in a 100 mL Schlenk flask. 30 mL of toluene was added to dissolve the mixture. Under a nitrogen atmosphere, cuprous iodide (571.35 mg, 3.0 mmol) and 1,10-phenanthroline (594.66 mg, 3.0 mmol) were added sequentially. The mixture was refluxed at 110°C for 12 h, and the reaction progress was monitored by TLC. After the reaction was completed, the system was cooled to room temperature, filtered, extracted with dichloromethane, and washed with saturated brine to remove impurities. The lower organic phase was collected, anhydrous magnesium sulfate was added, and the mixture was stirred for 10 h. After filtration, the solvent was evaporated under reduced pressure. The crude product was further purified by silica gel column chromatography (petroleum ether / dichloromethane = 10 / 1, v / v) as eluent, and the target compound was separated by gradient elution to obtain colorless oily liquid TPA-OCH3 (1.657 g, yield 78%). 1H NMR (400MHz, CDCl3), δ7.30-7.17(m,4H),7.03-6.93(t,5H),6.79-6.73(m,4H),3.78(s,3H). Such as Figure 12 shown.

[0086] 2) Synthesis of intermediate TPABO-OCH3

[0087]

[0088] To a 100 mL Schlenk flask, TPA-OCH3 (1.629 g, 4.6 mmol), bis(pinacolato)diboron (7.010 g, 27.6 mmol), and potassium acetate (2.708 g, 27.6 mmol) were added, and 30 mL of 1,4-dioxane was added to dissolve the mixture. Pd(dppf)Cl2 (201.94 mg, 0.27 mmol) was added under a nitrogen atmosphere. The mixture was transferred to an oil bath at 100°C and refluxed for 24 h. After completion of the reaction, the reaction was processed as above. Finally, the crude product was further purified by silica gel column chromatography (petroleum ether / dichloromethane = 1 / 1, v / v). The target compound was isolated by gradient elution to obtain TPABO-OCH3 (1.2922 g, 70% yield) as a colorless oil. 1 H NMR (400MHz, CDCl3), δ7.64(d,2H),7.23-7.15(t,2H),7.10-7.01(m,4H),6.99-6.91(t,3H),6.84-6.78(d,2H),3.78(s,3H),1.31(s,12H). Such as Figure 13 shown.

[0089] 3) Synthesis of intermediate TB-OCH3

[0090]

[0091] TPABO-OCH3 (1.204 g, 3.0 mmol), 2-bromoanthraquinone (0.947 g, 3.3 mmol) and tetrabutylammonium bromide (48.35 mg, 0.15 mmol) were weighed and placed in a 100 mL Schlenk bottle, 25 mL of toluene was added, and the mixture was stirred and dissolved at room temperature. Pd(Ph3)4(0) (173.33 mg, 0.15 mmol) and 3.75 mL of potassium carbonate aqueous solution (1.036 g, 7.5 mmol, 2 mol L) were added under nitrogen atmosphere. -1), refluxed at 110°C for 12 hours. After completion of the reaction, the system was cooled to room temperature, extracted with dichloromethane and washed with saturated brine to remove impurities. The lower organic phase was collected, anhydrous magnesium sulfate was added and stirred for 10 hours, filtered, and the solvent was evaporated under reduced pressure. The crude product was further purified by silica gel column chromatography (petroleum ether / ethyl acetate = 5 / 1, v / v) as eluent, and the target compound was isolated by gradient elution to obtain a red solid powder TB-OCH3 (1.169 g, yield 81%). 1 H NMR(400MHz, CDCl3), δ8.50(d,1H),8.36-8.27(m,3H),7.97(m,1H),7.82-7.76 (m,2H),7.61-7.55(d,2H),7.31-7.00(m,9H),6.92-6.85(d,2H),3.78(s,3H). Such as Figure 14 shown.

[0092] 4) Synthesis of intermediate TB-OH

[0093]

[0094] TB-OCH3 (0.962 g, 2.0 mmol) was added to a 50 mL round-bottom flask, dissolved in 20 mL of dichloromethane, and stirred in an ice-water bath for 20 min. Boron tribromide (500 μL, 5.0 mmol) was then slowly added dropwise under an ice-water bath, heated to 35 ° C, and refluxed for 24 h. After the reaction was completed, ice water was slowly added dropwise to the system under an ice-water bath to quench the residual boron tribromide. Subsequently, ethyl acetate was used for extraction and washed with saturated brine. The upper organic phase was collected and concentrated in vacuo to remove the solvent. The crude product was further purified by silica gel column chromatography (petroleum ether / ethyl acetate = 3 / 1, v / v), and the target compound was isolated by gradient elution to obtain TB-OH (471.32 mg, 50.4% yield) as a red solid powder. 1 H NMR(400MHz,DMSO),δ9.56(s,1H),8.33(s,1H),8.25-8.09(m,4H),7.96-7.88(m, 2H),7.76-7.67(m,2H),7.52-7.41(d,2H),7.10-6.93(m,7H),6.85-6.78(d,2H). Such as Figure 15 shown.

[0095] 5) Synthesis of red light TADF functional compound TB-Alk

[0096]

[0097] TB-OH (467.52 mg, 1.0 mmol), potassium carbonate (414.63 mg, 3.0 mmol), and tetrabutylammonium bromide (16.12 mg, 0.05 mmol) were weighed and added to a 50 mL round-bottom flask. 15 mL of acetone was added for dissolution, followed by the slow dropwise addition of propyne bromide (713.80 mg, 6.0 mmol). The mixture was refluxed at 60°C for 24 h. After completion of the reaction, the reaction was processed as above. Finally, the crude product was further purified by silica gel column chromatography (petroleum ether / ethyl acetate = 5 / 1, v / v), and the target compound was isolated by gradient elution to obtain TB-Alk (247.53 mg, 49.0% yield) as a red solid powder. 1 H NMR(400MHz, CDCl3), δ8.47(s,1H),8.34-8.27(m,4H),7.95(d,2H),7.80-7.75(m,2H), 7.59(d,2H),7.41-7.33(d,2H),7.18-6.94(m,9H),4.72(d,2H),2.58(d,1H).ESI-MSm / z calcd.for[C 35 H 23 NO2]=505.1678,found 505.1668. Figure 16 shown.

[0098] 4. Target Polymer PDFC-DT x -TB y Synthesis

[0099]

[0100] 1) Target polymer PDFC-DT 99 Synthesis of -TB1

[0101] Prepare 1.97 mg mL of tetrahydrofuran as solvent -1 The polymer PDFC-N3 (128.76 mg, containing -N3 group 0.13 mmol) and TB-Alk solution (334.0 μL, 0.0013 mmol, 1.97 mg mL -1) was placed in a 25 mL Schlenk tube, evacuated and filled with nitrogen three times. Under a nitrogen atmosphere, cuprous bromide (40.28 mg, 0.28 mmol) and N,N,N',N",N"-pentamethyldiethylenetriamine (PMDETA, 26.00 mg, 0.15 mmol) were added. 5 mL of purified tetrahydrofuran was added, stirred to dissolve, and reacted at 60°C in the dark for 12 h. The reaction progress was monitored by TLC. After the red-light molecule TB-Alk reacted completely, the blue-light molecule DT-Alk (111.47 mg, 0.16 mmol) was added and the reaction continued for 24 h. After the reaction was completed, it was cooled to room temperature and stirred in the open air for 4 h. 1,4,7,10-tetraazacyclododecane (134.40 mg, 0.78 mmol) was added and the reaction continued in the open air with stirring for 12 h to fully convert the copper ions. The reaction was then extracted with dichloromethane and washed multiple times with saturated brine. The lower organic phase was collected and concentrated to remove the solvent. A small amount of tetrahydrofuran was added to fully dissolve the polymer, and the solution was slowly added dropwise to rapidly stirred ice methanol to induce precipitation of the target polymer. The solid powder was collected by filtration, and the crude product was extracted with methanol and acetone for three days each to obtain a yellow solid powder PDFC-DT. 99 -TB1 (110.38 mg, 58.0% yield). 1 H NMR(400MHz, CDCl3), δ9.07(s,2H),8.68(m,4H),8.32-8.17(m,6H),8.07(s,1H),7.75-7.30(m,30H),7.26(s,2H),7.16-6.93(m ,12H),6.78-6.72(d,4H),4.33(s,3H),4.07-3.88(d,8H),3.60(s,1H),1.98-1.72(m,12H),1.60-1.41(m,12H).GPC(THF,PS):M n =2.82×10 4 ,PDI=1.77. Figure 18 shown.

[0102] 2) Target polymer PDFC-DT 97 Synthesis of -TB3

[0103] The polymer PDFC-N3 (128.76 mg, containing 0.13 mmol of -N3 group) and TB-Alk solution (1.0 mL, 0.0039 mmol, 1.97 mg mL -1), placed in a 25mL Schlenk tube, evacuated and filled with nitrogen three times, and under a nitrogen atmosphere, added cuprous bromide (40.28mg, 0.28mmol) and PMDETA (26.00mg, 0.15mmol), added 5mL of refined tetrahydrofuran, stirred and dissolved, and reacted at 60℃ in the dark for 12h. The reaction progress was monitored by TLC. After the red light molecule TB-Alk reacted completely, the blue light molecule DT-Alk (109.27mg, 0.15mmol) was added and the reaction continued for 24h. After the reaction was completed, the treatment method was the same as above, and finally a yellow solid powder PDFC-DT was obtained. 97 -TB3 (112.46 mg, 59.2% yield). 1 H NMR(400MHz, CDCl3), δ9.07(s,2H),8.68(m,4H),8.32-8.17(m,6H),8.07(s,1H),7.75-7.30(m,30H),7.26(s,2H),7.16-6.93(m ,12H),6.78-6.72(d,4H),4.33(s,3H),4.07-3.88(d,8H),3.60(s,1H),1.98-1.72(m,12H),1.60-1.41(m,12H).GPC(THF,PS):M n =2.65×10 4 ,PDI=2.31. Figure 18 shown.

[0104] 3) Target polymer PDFC-DT 95 Synthesis of -TB5

[0105] Weigh the polymer PDFC-N3 (128.76 mg, containing 0.13 mmol of -N3 group) and TB-Alk (3.28 mg, 0.0065 mmol) and place it in a 25 mL Schlenk tube. Vacuum and fill with nitrogen three times, and add cuprous bromide (40.28 mg, 0.28 mmol) and PMDETA (26.00 mg, 0.15 mmol) under a nitrogen atmosphere. Add 5 mL of refined tetrahydrofuran, stir and dissolve, and react at 60 ° C in the dark for 12 hours. Monitor the reaction progress by TLC. After the red light molecule TB-Alk reacts completely, add the blue light molecule DT-Alk (106.96 mg, 0.15 mmol) and continue the reaction for 24 hours. After the reaction is completed, the treatment method is the same as above, and the orange-yellow solid powder PDFC-DT is finally obtained. 95 -TB5 (115.38 mg, 60.7% yield). 1H NMR(400MHz, CDCl3), δ9.07(s,2H),8.68(m,4H),8.32-8.17(m,6H),8.10(s,0.1H),8.07(s,1H),7.99(s,0.3H),7.75-7.30(m,30H),7.26(s,2H ),7.16-6.93(m,12H),6.78-6.72(d,4H),4.33(s,3H),4.07-3.88(d,8H ),3.60(s,1H),1.98-1.72(m,12H),1.60-1.41(m,12H).GPC(THF,PS):M n =2.24×10 4 ,PDI=2.61. Figure 18 shown.

[0106] 4) Target polymer PDFC-DT 90 -TB 10 Synthesis

[0107] Weigh the polymer PDFC-N3 (128.76 mg, containing 0.13 mmol of -N3 group) and TB-Alk (6.57 mg, 0.013 mmol) and place it in a 25 mL Schlenk tube. Vacuum and fill with nitrogen three times, and add cuprous bromide (40.28 mg, 0.28 mmol) and PMDETA (26.00 mg, 0.15 mmol) under a nitrogen atmosphere. Add 5 mL of refined tetrahydrofuran, stir and dissolve, and react at 60 ° C in the dark for 12 hours. Monitor the reaction progress by TLC. After the red light molecule TB-Alk reacts completely, add the blue light molecule DT-Alk (100.21 mg, 0.14 mmol) and continue the reaction for 24 hours. After the reaction is completed, the treatment method is the same as above, and the orange-red solid powder PDFC-DT is finally obtained. 90 -TB 10 (113.58 mg, 59.7% yield). 1 H NMR(400MHz, CDCl3), δ9.07(s,2H),8.68(m,4H),8.32-8.17(m,6H),8.10(s,0.2H),8.07(s,1H),7.99(s,0.6H),7.75-7.30(m,30H),7.26(s,2H ),7.16-6.93(m,12H),6.78-6.72(d,4H),4.33(s,3H),4.07-3.88(d,8H ),3.60(s,1H),1.98-1.72(m,12H),1.60-1.41(m,12H).GPC(THF,PS):M n =2.20×104 ,PDI=1.72. Figure 18 shown.

[0108] 5) Target polymer PDFC-DT 85 -TB 15 Synthesis

[0109] Weigh the polymer PDFC-N3 (128.76 mg, containing 0.13 mmol of -N3 group) and TB-Alk (9.85 mg, 0.0195 mmol) and place it in a 25 mL Schlenk tube. Vacuum and fill with nitrogen three times, and add cuprous bromide (40.28 mg, 0.28 mmol) and PMDETA (26.00 mg, 0.15 mmol) under a nitrogen atmosphere. Add 5 mL of refined tetrahydrofuran, stir and dissolve, and react at 60 ° C in the dark for 12 hours. Monitor the reaction progress by TLC. After the red light molecule TB-Alk reacts completely, add the blue light molecule DT-Alk (95.43 mg, 0.13 mmol) and continue the reaction for 24 hours. After the reaction is completed, the treatment method is the same as above, and the red solid powder PDFC-DT is finally obtained. 85 -TB 15 (118.80 mg, 62.5% yield). 1 H NMR(400MHz, CDCl3), δ9.07(s,2H),8.68(m,4H),8.32-8.17(m,6H),8.10(s,0.35H),8.07(s,1H),7.99(s,1H),7.75-7.30(m,30H),7.26(s,2H ),7.16-6.93(m,12H),6.78-6.72(d,4H),4.33(s,3H),4.07-3.88(d,8H ),3.60(s,1H),1.98-1.72(m,12H),1.60-1.41(m,12H).GPC(THF,PS):M n =1.69×10 4 ,PDI=1.90. Figure 18 shown.

[0110] Example 2 Application

[0111] Using PDFC-DT in Example 1 x -TB y (x=99,97,95,90,85) was used as the light-emitting layer to prepare OLED devices using a solution method. The OLED device structure was ITO / PEDOT:PSS (40nm) / PVK:poly-TPD (4:1, 30nm) / EML:PDFC-DT x -TBy The non-doped OLED devices of (20nm) / TmPyPB(40nm) / CsF(1.4nm) / Al(50nm) were named P1, P3, P5, P10, and P15 respectively, and their luminance, current efficiency, and chromaticity coordinates were measured. The results are as follows Figure 19 、 Figure 20 As shown in Table 1:

[0112] Table 1 Electroluminescent properties of non-doped OLED devices P1-P15

[0113]

[0114] Among them, V on Representative devices at 1 cd m -2 The turn-on voltage at the brightness of EL represents the EL emission peak; L max Represents maximum brightness; CE max Stands for maximum current efficiency; EQE max stands for maximum external quantum efficiency; CIE stands for chromaticity coordinates at maximum brightness.

[0115] Using PDFC-DT in Example 1 x -TB y The OLED devices P1, P3, P5, P10, and P15, prepared by the solution method with (x=99, 97, 95, 90, 85) as the light-emitting layer, have an EL emission peak range of 410 to 800 nm. As the content of TB red light units attached to the side chains increases, the device emission color gradually transitions from blue-green to white and then to red. Among them, the EL spectra of P3, P5, and P10 have strong dual emission peaks at 509 nm and 610 nm. The CIE coordinates at maximum brightness are (0.33, 0.40), (0.37, 0.41), and (0.36, 0.38), respectively, which are within the visible white light range and exhibit warm white light emission.

[0116] Using PDFC-DT in Example 1 97 -TB3 film and AFM images were taken of it, such as Figure 21 The AFM image has a relatively uniform color, and no obvious large aggregated particles appear on the surface, indicating that the film surface is flat and smooth, and the target polymer has good film-forming properties.

[0117] Using PDFC-DT in Example 1 x -TB y (x=99,97,95,90,85)TG and DSC tests were carried out at a heating rate of 10℃ / min under nitrogen atmosphere, as shown in Figure 2. Figure 22As shown, the target polymer exhibits a thermal decomposition temperature greater than 309°C and a glass transition temperature between 139°C and 157°C, and has excellent thermal stability.

[0118] The foregoing description is merely an example of the present invention and does not limit the present invention. The present invention is intended to provide a thermally activated delayed fluorescent polymer white light-emitting material. An OLED device fabricated using the compound of the present invention as the light-emitting layer material has room for further improvement in the device structure and performance. Various improvements and modifications may be made to the present invention without departing from the principles of the present invention, and such improvements and modifications fall within the scope of protection of the claims.

Claims

1. A TADF polymer material, characterized in that The material is PDFC-DT x -TB y , whose chemical structure is shown in formula (1): Among them, R1- is a blue light functional compound group, and the blue light functional compound is a biscarbazolyl-triazine compound; R2- is a red light functional compound group, and the red light functional compound is a triphenylamine-anthraquinone compound.

2. The TADF polymer material according to claim 1, characterized in that The biscarbazolyl-triazine compound is The triphenylamine-anthraquinone compound is In addition, x and y on the polymer main chain respectively represent the molar numbers of the blue light unit and the red light unit attached to the polymer main chain, and the value range of x:y is 97:3-90:

10.

3. A method for preparing a TADF polymer material, characterized in that: The following steps are involved: 1) Preparation of polymer backbone PDFC-N3 2) Preparation of blue light functional compound DT-Alk 3) Preparation of red light functional compound TB-Alk 4) Synthesis of PDFC-DT x -TB y 4. The method for preparing a TADF polymer material according to claim 3, wherein: In step 1), the preparation method of the polymer PDFC-Br is as follows: 3,6-CzBr and DF-BO are mixed, degassed with nitrogen three times, tetrahydrofuran, deionized water, cesium carbonate, tetrabutylammonium bromide and tetrakis(triphenylphosphine)palladium are added, and the reaction is carried out at 50-70°C in the dark for 50-70h, and then phenylboric acid and iodobenzene are added for end-capping reaction respectively. After the reaction is completed, the white solid powder is separated and purified to obtain the polymer PDFC-Br; the amount ratio of the 3,6-CzBr, DF-BO, tetrahydrofuran, deionized water, cesium carbonate, tetrabutylammonium bromide, tetrakis(triphenylphosphine)palladium, phenylboric acid, and iodobenzene is 3.3mmol:3.3mmol:25-35mL:1.5mL:21.0mmol:0.71mmol:0.40mmol:1.01mmol:1.02mmol; When preparing the polymer main chain PDFC-N3, the polymer PDFC-Br is added with sodium azide and tetrabutylammonium bromide, and then tetrahydrofuran is added. The mixture is stirred until the solution is clear, and the mixture is reacted at 50-70° C. in the dark for 30-50 hours. After the reaction is completed, the white solid powder is separated and purified to obtain the polymer PDFC-N3. The dosage ratio of the PDFC-Br, sodium azide, tetrabutylammonium bromide and tetrahydrofuran is 1.00 mmol:10.0 mmol:0.2 mmol:12-18 mL.

5. The method for preparing a TADF polymer material according to claim 4, characterized in that: The preparation method of 3,6-CzBr is as follows: Dissolve 3,6-dibromocarbazole in tetrahydrofuran, slowly add sodium hydride, observe bubbles forming in the bottle, add 1,6-dibromohexane after stabilization, and react at 45-55°C for 10-15 hours. After the reaction is complete, separate and purify to obtain a white flocculent substance, namely 3,6-CzBr; wherein the amount ratio of 3,6-dibromocarbazole, tetrahydrofuran, sodium hydride, and 1,6-dibromohexane is 9 mmol:18-22 mL:24 mmol:22 mmol; The preparation method of DF-BO is as follows: dissolving bisphenol fluorene, 1,6-dibromohexane and potassium carbonate in acetone, and reacting under reflux at 55-65° C. for 20-28 hours. After the reaction is completed, separation and purification are performed to obtain a colorless oily liquid DF-Br. Dissolve DF-Br, 4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolane-2-yl)phenol and cesium carbonate in acetone, reflux at 50-70°C for 20-28h, and separate and purify to obtain a white solid powder DF-BO; The usage ratio of bisphenol fluorene, 1,6-dibromohexane, potassium carbonate and acetone is 3mmol:24mmol:24mmol:20-30mL; The usage ratio of the DF-Br, 4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolane-2-yl)phenol, cesium carbonate and acetone is 1.52 mmol:12 mmol:12 mmol:15-25 mL.

6. The method for preparing a TADF polymer material according to claim 3, wherein: Step 2) The method for preparing the blue light functional compound DT-Alk is: First, prepare DCzTrz-OH: dissolve DCzTrz-OCH3 in dichloromethane, stir in an ice-water bath for 15-25 minutes, then slowly add boron tribromide dropwise in an ice-water bath, heat to 30-40°C, condense and reflux for 20-28 hours, and separate and purify to obtain yellow solid powder DCzTrz-OH; Weigh DCzTrz-OH, potassium carbonate, and tetrabutylammonium bromide, mix, add acetone, then slowly add propyne bromide dropwise, reflux at 50-70°C for 20-28 hours, and then separate and purify to obtain a yellow solid powder DT-Alk; The dosage ratio of DCzTrz-OCH3, dichloromethane and boron tribromide is 1.5mmol:15-25mL:3.75mmol; The usage ratio of DCzTrz-OH, potassium carbonate, tetrabutylammonium bromide, acetone and propyne bromide is 1.2 mmol:3.6 mmol:0.06 mmol:12-20 mL:7.2 mmol.

7. The method for preparing a TADF polymer material according to claim 3, wherein: Step 3) The method for preparing the red light functional compound TB-Alk is: First, prepare TB-OH: dissolve TB-OCH3 in dichloromethane and stir in an ice-water bath for 15-25 minutes. Then, slowly add boron tribromide dropwise in an ice-water bath, heat to 30-40°C, condense and reflux for 22-28 hours, and separate and purify to obtain a red solid powder TB-OH. The prepared TB-OH, potassium carbonate and tetrabutylammonium bromide were mixed, acetone was added to dissolve, and then propyne bromide was slowly added dropwise. The mixture was refluxed at 50-70°C for 22-28 hours, and then separated and purified to obtain a red solid powder TB-Alk; The usage ratio of TB-OCH3, dichloromethane and boron tribromide is 2.0mmol:15-25mL:5.0mmol; the usage ratio of TB-OH, potassium carbonate, tetrabutylammonium bromide, acetone and propyne bromide is 1.0mmol:3.0mmol:12-18mL:6.0mmol.

8. The method for preparing a TADF polymer material according to claim 3, wherein: Step 4) Synthesis of PDFC-DT x -TB y The method comprises the following steps: weighing polymer PDFC-N3 and TB-Alk solution respectively, adding cuprous bromide and N,N,N',N",N"-pentamethyldiethylenetriamine under protective gas atmosphere, adding tetrahydrofuran, stirring and dissolving, reacting at 50-70°C in the dark for 10-15 hours, adding blue light molecule DT-Alk, continuing to react for 20-28 hours, cooling to room temperature after the reaction, stirring for 3-6 hours, adding 1,4,7,10-tetraazacyclododecane, continuing to stir and react in the open air for 10-14 hours, and separating and purifying to obtain yellow solid powder PDFC-DT x -TB y The usage ratio of PDFC-N3, TB-Alk, cuprous bromide, N,N,N',N",N"-pentamethyldiethylenetriamine and tetrahydrofuran is 128.76 mg:0.0039-0.013 mmol:40.28 mg:26.00 mg:4-6 mL.

9. The method for preparing a TADF polymer material according to claim 8, characterized in that: In step 4), the protective gas is nitrogen.

10. Use of the TADF polymer material according to claim 1 as a light-emitting layer in an organic electroluminescent device.

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