Excited state proton transfer OLED (Organic Light Emitting Diode) material based on heat excitons as well as preparation method and application of excited state proton transfer OLED material

Abstract

The invention discloses an excited state proton transfer OLED material based on heat excitons and a preparation method and application thereof, and belongs to the technical field of organic electroluminescent materials, 9, 9-dimethyl-10-(4-(phenylsulfonyl) phenyl)-9, 10-dihydroacridine is used as a substituent group, and two molecules with different luminescence colors in a formula I and a formula II are finally prepared; the name of the formula I is 2-(benzothiazole-2-yl)-4-(9, 9-dimethyl-10-(4-phenylsulfonyl) phenyl)-9, 10-dihydroacridine-2-yl) phenol, the name of the formula II is 2-benzothiazole-2-yl)-5-(9, 9-dimethyl-10-(4-phenylsulfonyl) phenyl)-9, 10-dihydroacridine-2-yl) phenol, the maximum external quantum efficiency of the prepared yellow and white light OLED device is 5.33%, and the maximum external quantum efficiency of the prepared yellow and white light OLED device is 5.33%. The maximum external quantum efficiency of the prepared blue and white light OLED device is 7.54%.

Description

Technical Field

[0001] The present invention belongs to the technical field of organic electroluminescent materials, and in particular relates to an excited-state proton transfer OLED material based on thermal excitons, and a preparation method and application thereof. Background Art

[0002] Organic Light-Emitting Diodes (OLEDs) have become the mainstream display technology in various electronic instrument displays and lighting fields, becoming an indispensable part of our daily lives. Compared with traditional light sources, OLEDs have become increasingly advantageous, such as self-luminescence, thin design, wide viewing angle, high contrast, low power consumption, fast response speed, and flexible application. Therefore, since their inception, OLEDs have been deeply studied and widely used. OLED devices generally consist of a transparent substrate (usually based on indium tin oxide (ITO)) as the anode, a metal material (such as Ag and Al) as the cathode, and multiple thin organic semiconductor layers sandwiched between the two. The luminescence process mainly involves carrier injection and transport, exciton recombination, and exciton luminescence. Charge carriers, electrons and holes, are generated from the cathode and anode, respectively, by an applied bias voltage. Electrons then overcome numerous potential barriers, pass through the electron injection layer (EIL), and then through the electron transport layer (ETL) to the emissive layer. Simultaneously, holes also cross potential barriers, injecting into the hole injection layer (HIL), then through the hole transport layer (HTL) to the emissive layer. All charge carriers recombine in the emissive layer to form excitons. Finally, the excitons radiate, transitioning back to the ground state and causing electroluminescence. Light is generated by the recombination and radiative transition of electrons and holes within the emissive layer. Therefore, by selecting the materials in the emissive layer to meet specific requirements, OLEDs can be designed to emit light with varying CIE (Commission Internationale de L'Eclairage) coordinates, CCT (Correlated Color Temperature), and CRI (Color Rendering Index). OLED efficiency continues to improve, with internal quantum efficiency nearing its limit, reaching 100%. OLEDs have also achieved widespread commercialization, including in smartphones, high-end TVs, wearables, solid-state lighting, and augmented / virtual reality (AR / VR) devices. However, OLED technology still faces key challenges in material design and device structure. Further innovation is needed to improve the efficiency, lifespan, and stability of OLED devices. However, it is foreseeable that the relentless pursuit of high-quality OLED materials and devices will continue, driven by the pursuit of higher efficiency when integrated into devices.

[0003] Recently, a growing number of scientists have reported on "hot exciton" OLEDs. Unlike TADF, the RISC process occurs between a high-lying triplet state (Tn, n ≥ 2) and a singlet state (Sm, m ≥ 1). To achieve efficient hRISC, the internal conversion (IC) between Tn and T1 must be suppressed to accelerate hRISC from Tn to Sm. According to photochemical principles, the energy gap difference before and after the transition is inversely proportional to the IC and hRISC rates. Therefore, "hot exciton" materials typically have a small Tn-Sm energy gap to enhance the hRISC rate and a large Tn-T1 energy gap to suppress the IC rate. Ideally, when IC is completely suppressed and the hRISC rate is very high, all triplet states can be converted to singlet excitons, achieving an IQE of 100%. Furthermore, "hot excitons" can be incorporated into "dual-host" device architectures to improve device efficiency and reduce roll-off.

[0004] Color-tunable OLED devices, which can achieve wide-range or full-color tunable emission, bring new possibilities to display, lighting, and optoelectronic applications, showing broad application prospects in white light OLEDs, information encryption, bioengineering, and other fields. Over the past few decades, the preparation technology of high-performance color-tunable OLEDs has been vigorously researched and promoted.

[0005] To achieve color gamut tunability in OLED devices, multi-component luminescence is typically required to achieve electroluminescence covering the entire visible light range (380-780nm). Depending on the requirements, multiple luminescent materials, such as the three primary colors (red, green, and blue) or complementary colors (such as yellow and blue), are typically mixed to cover the entire visible light region and achieve tunable full-color emission. This is typically achieved using a multi-emitting layer (M-EML) stack or a single-emitting layer (S-EML). An M-EML isolates the different luminescent materials into separate layers. This allows for precise control of the doping ratio of each layer and the exciton ratio of each color, enabling the production of tunable full-color emission as desired. Therefore, it is necessary to control the emission balance of each layer, ensuring that each color emits a suitable ratio. Precise control of the exciton ratio is crucial to achieving an ideal light source. For example, to achieve a more balanced recombination of holes and electrons, a thin exciton blocking layer can be added between the different EMLs to control the number of excitons in each EML. Materials with "thermoexciton" properties can be introduced into the preparation of color-tunable OLED devices to prepare high-performance OLEDs with simple device manufacturing, high spectral repeatability and good color stability. Summary of the Invention

[0006] Technical problems to be solved: In order to overcome the deficiencies in the prior art, this application proposes an excited-state proton transfer OLED material based on thermal excitons and its preparation method and application, so as to solve technical problems in the prior art such as difficult device preparation process, low spectral repeatability and poor color stability.

[0007] Technical solution:

[0008] An excited-state proton transfer OLED material based on a thermal exciton, wherein the excited-state proton transfer OLED material based on a thermal exciton uses 9,9-dimethyl-10-(4-(phenylsulfonyl)phenyl)-9,10-dihydroacridine as a substituent, and is substituted at the para-position and meta-position of the hydroxyl group through a Suzuki coupling reaction, thereby finally preparing two molecules of formula I and formula II with different luminescent colors; the name of formula I is 2-(benzothiazol-2-yl)-4-(9,9-dimethyl-10-(4-phenylsulfonyl)phenyl)-9,10-dihydroacridine-2-yl)phenol, and the name of formula II is 2-benzothiazol-2-yl)-5-(9,9-dimethyl-10-(4-phenylsulfonyl)phenyl)

[0009] -9,10-dihydroacridin-2-yl)phenol, the structural formulas are as follows:

[0010]

[0011] The preparation method of the excited state proton transfer OLED material based on thermal excitons, the preparation of 2-(benzothiazol-2-yl)-4-(9,9-dimethyl-10-(4-phenylsulfonyl)phenyl)-9,10-dihydroacridin-2-yl)phenol described in Formula I comprises the following steps:

[0012] Step 1: Take 10g of sodium p-fluorobenzenesulfinate and 26-27g of diphenyltrifluoromethanesulfonic acid iodide, add them to a dry 250mL three-necked flask, connect the condenser, seal the device with a rubber stopper and sealing film, use a double-row tube to evacuate and purge with nitrogen three times, and insert a nitrogen balloon, then fix the device in an oil bath pot, add 120mL of solvent N,N-dimethylformamide DMF under a nitrogen environment, and heat at 90°C for 24 hours; after the reaction is completed, remove the high-boiling point DMF by reduced pressure distillation, then extract with water and dichloromethane, separate the lower organic phase, add anhydrous sodium sulfate to dry, remove the filtered organic solvent, purify the crude product by silica gel column, concentrate and recrystallize with n-hexane to finally obtain white solid 1-fluoro-4-phenylsulfonylbenzene;

[0013] Step 2: Take 5g of 9,9-dimethyl-9,10-dihydroacridine and add it to a dry 250mL three-necked flask, take 4-5g of N-bromosuccinimide and add it to the dropping funnel, seal the device with a rubber stopper and a sealing film, use a double-row tube to evacuate and blow nitrogen three times, and insert a nitrogen balloon, then place the entire device in an ice-water bath, add N,N-dimethylformamide DMF to the three-necked flask and the dropping funnel respectively, open the control valve so that the falling speed of the droplet remains stable, after the solution in the dropping funnel is completely dripped, heat to room temperature and react for 6 hours, remove the high-boiling DMF by reduced pressure distillation, then extract with water and dichloromethane, separate the lower organic phase, add anhydrous sodium sulfate to dry, remove the organic solvent obtained by filtration, and purify the crude product by silica gel column to finally obtain a dark green solid intermediate 2-bromo-9,9-dimethyl-9,10-dihydroacridine;

[0014] Step 3: Take 5-10 g of 2-bromo-9,9-dimethyl-9,10-dihydroacridine prepared in the second step, 1-2 g of 1-fluoro-4-phenylsulfonylbenzene prepared in the first step and sodium hydride, add them to a dry 500 mL three-necked flask, connect the condenser, seal the device with a rubber stopper and sealing film, use a double-row tube to evacuate and bubbling nitrogen three times, insert a nitrogen balloon, and then fix the device in an oil bath. Under nitrogen environment, add 100 mL The solvent N,N-dimethylformamide (DMF) was heated at 100°C for 12 hours. After the reaction was completed, the high-boiling DMF was removed by distillation under reduced pressure, and then the mixture was extracted with water and dichloromethane. The lower organic phase was separated and dried over anhydrous sodium sulfate. The organic solvent was removed by filtration. The crude product was purified by silica gel column, concentrated, and recrystallized from n-hexane to obtain a light green solid 9,9-dimethyl-10-(4-(phenylsulfonyl)phenyl)-9,10-dihydroacridine.

[0015] Step 4: Take 1-2 g of 9,9-dimethyl-10-(4-(phenylsulfonyl)phenyl)-9,10-dihydroacridine prepared in step 3, 0.3-0.6 g of 2-(benzothiazol-2-yl)-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenol, and 0.1-0.2 g of tetrakistriphenylphosphine palladium Pd(Phh3)4 and add them to 50 mL of dry In a Schlenk reaction tube, vacuum and nitrogen were purged three times using a double-row tube, and 20 mL of a solvent mixed with tetrahydrofuran and toluene in a volume ratio of 1:1 was added, followed by 2.5 mL of a 2 mol / L mixed solution of potassium carbonate and potassium fluoride dissolved in deionized water, wherein 680-690 mg of potassium carbonate K2CO3 and 290-300 mg of potassium fluoride KF were added; the reaction apparatus was then fixed in an oil bath and heated at 90°C for 24 hours. After the reaction was completed, the solvent was removed by distillation under reduced pressure, and then extracted with water and dichloromethane. The lower organic phase was separated and dried over anhydrous sodium sulfate. The organic solvent obtained by filtration was removed, and the crude product was purified by silica gel column, concentrated, and recrystallized with n-hexane to finally obtain 0.1-0.3 g of a light yellow solid material of formula I with a yield of 30-35%; hydrogen spectrum analysis: 1H NMR (400MHz, DMSO-d6) δ11.61 (s, 1H), 8.32 (d, J = 2.3Hz, 1H), 8.25 (d, J = 8.3Hz, 2H), 8.14 (d, J = 7.9Hz, 1H), 8.08(t,J=7.8Hz,3H), 7.79–7.66(m,8H), 7.54(ddt,J=6.0,4.2,2.0Hz,2H), 7.45(t,J=7.6Hz,1H) , 7.31(dd,J=8.6,2.1Hz,1H), 7.15(d,J=8.6Hz,1H), 7.04–6.94(m,3H), 6.26(d,J=8.5Hz,1H), 6.18(dd ,J=7.9,1.5Hz,1H),1.69(s,6H).MALDI-TOFm / z:649.7[M]+.HRMS(EI)m / z:651.1777[M]+.Anal.Calcd for C 40 H 30 N2O3S2(651.1771), the reaction formula is:

[0016]

[0017] Furthermore, the preparation of 2-benzothiazol-2-yl)-5-(9,9-dimethyl-10-(4-phenylsulfonyl)phenyl)-9,10-dihydroacridin-2-yl)phenol of Formula II comprises the following steps:

[0018] Step 1: Take 1-2 g of 9,9-dimethyl-10-(4-(phenylsulfonyl)phenyl)-9,10-dihydroacridine, 0.5-1 g of 2-(benzothiazol-2-yl)-5-(4,4,5,5-tetramethyl-1,3,2-dioxaboran-2-yl)phenol, and 0.1-0.3 g of tetrakistriphenylphosphine palladium Pd(Phh3)4, add them into a dry 50 mL Schlenk reaction tube, add 20 mL of a solvent mixed with tetrahydrofuran and toluene in a volume ratio of 1:1, and then add 5 mL of a 2 mol / L mixed solution of potassium carbonate K2CO3 and potassium fluoride KF dissolved in deionized water, wherein potassium carbonate K2CO3 1.3-1.4 g, potassium fluoride KF The reaction apparatus was then fixed in an oil bath and heated at 90°C for 24 hours. After the reaction was completed, the solvent was distilled off under reduced pressure, and then extracted with water and dichloromethane. The lower organic phase was separated and dried over anhydrous sodium sulfate. The organic solvent obtained by filtration was removed, and the crude product was purified by silica gel column, concentrated, and recrystallized from n-hexane to obtain 0.2-0.4 g of a light yellow solid material of formula II in a yield of 25-30%; hydrogen spectrum analysis 1HNMR (400 MHz, DMSO-d6) δ 8.27 (d, J = 8.4 Hz, 3H), 8.11 (ddd, J = 32.5, 16.8, 8.4 Hz, 7H), 7.82 (d, J = 2.1 Hz, 1H), 7.77(d,J=7.3Hz,1H), 7.70(t,J=8.7Hz,4H), 7.55(d,J=7.5Hz,2H), 7.44(t,J=7.6Hz,2H), 7.36(d,J=8.6Hz,1H), 7.30(d,J=5.1Hz,2H), 7 .04–6.93(m,3H),6.21(d,J=8.6Hz,2H),6.14–6.10(m,1H),1.70(s,6H).MALDI-TOFm / z:649.2[M]+.HRMS(EI)m / z:651.1779[M]+.Anal.Calcd for C 40 H 30 N2O3S2(651.1771); the reaction formula is:

[0019]

[0020] The present application also discloses the application of excited-state proton transfer OLED materials based on thermal excitons in solid-state light-emitting films and OLED devices: solid-state light-emitting films and OLED devices with different luminous colors of blue, cool white, white, warm white or yellow light are obtained by changing the position and concentration of substituents. The solid-state light-emitting films and OLED devices use DPEPO as a single host material or CBP and TPBi as a dual host material. The solid-state film of Formula I exhibits yellow light, and the solid-state film of Formula II exhibits blue light.

[0021] As a preferred technical solution of the present application: as the doping concentration of the material of formula I increases from 0.5%, 1%, 2.5%, and 20%, the luminous color of its solid-state film and its OLED device gradually changes from cool white, pure white, warm white to yellow; the EQEmax, CIE and CCT indexes of the warm white light, pure white light and cold white light devices are 5.33%, (0.41, 40), 3361K, 4.00%, (0.33, 33), 5096K and 4.00%, (0.31, 0.32), 6886K, respectively, among which the CRI indexes of the pure white light and cold white light devices are 85.1 and 90.8.

[0022] As a preferred technical solution of the present application: as the doping concentration of the material of Formula II increases by 2.5% to 20%, the luminous color of the device remains stable in the sky blue light range, the color coordinate variation range is (Δ±0.005, Δ±0.01), and the EQEmax is stable in the range of 7.25 to 7.54%.

[0023] As a preferred technical solution of the present application: Formula I and Formula II achieve efficient utilization of excitons through reverse intersystem crossing, and their single-body OLED devices can achieve an exciton utilization rate of 55% to 65%, and their dual-body OLED devices can achieve an exciton utilization rate of 73% to 88%.

[0024] As a preferred technical solution of the present application: the OLED device is a multi-layer dual-body OLED device stacked up and down, which comprises, from bottom to top, an ITO substrate, an anode layer, a hole injection layer, a hole transport layer, an electron blocking layer, an organic light-emitting layer, a hole blocking layer, an electron injection layer, and a cathode layer; the material of the anode layer is an inorganic material, which is indium tin oxide or indium zinc oxide; the material of the hole injection layer is MoO3; the thickness of the hole injection layer is 1-2nm; the material of the hole transport layer is TAPC; the thickness of the hole transport layer is 40-50nm; the material of the electron blocking layer is TCTA ; The thickness of the electron blocking layer is 10-20nm; the material of the organic light-emitting layer is the main material CBP and TPBi doped with materials of formula I and formula II with high exciton utilization rate; the thickness of the organic light-emitting layer is 30-40nm; the doping concentration of the organic light-emitting layer is 0.5%-20%; the material of the hole blocking layer is TPBi; the thickness of the hole blocking layer is 50-60nm; the material of the electron injection layer is LiF; the thickness of the electron injection layer is 0.5-1nm; the material of the cathode layer is any one of gold, silver, copper, aluminum, and magnesium; the thickness of the cathode layer is 100nm.

[0025] As a preferred technical solution of the present application: the OLED device is a multi-layered single-body OLED device stacked up and down, which comprises, from bottom to top, an ITO substrate, an anode layer, a hole injection layer, a hole transport layer, an electron blocking layer, an organic light-emitting layer, a hole blocking layer, an electron injection layer, and a cathode layer; the material of the anode layer is an inorganic material, which is indium tin oxide or indium zinc oxide; the material of the hole injection layer is MoO3; the thickness of the hole injection layer is 1-2nm; the material of the hole transport layer is mcp or TAPC; the thickness of the hole transport layer is 40-50nm; the material of the electron blocking layer is TCTA; The thickness of the electron blocking layer is 10-20 nm; the material of the organic light-emitting layer is a doping of a main material DPEPO or CBP with materials having high exciton utilization efficiency of formula I and formula II; the thickness of the organic light-emitting layer is 30-40 nm; the doping concentration of the organic light-emitting layer is 0.5%-20%; the material of the hole blocking layer is TPBi or TmPyPB; the thickness of the hole blocking layer is 50-60 nm; the material of the electron injection layer is LiF; the thickness of the electron injection layer is 0.5-1 nm; the material of the cathode layer is any one of gold, silver, copper, aluminum, and magnesium; and the thickness of the cathode layer is 100 nm.

[0026] Principle explanation: The present invention studies two ESIPT materials, Formula I and Formula II, and applies the molecular design paradigm of thermal excitons and TADF to ESIPT molecules, introducing near-planar electron donor groups to construct a rigid molecular skeleton to reduce molecular vibration and increase molar absorptivity, thereby improving the low fluorescence quantum yield of ESIPT; at the same time, through effective electron orbital coupling, the utilization rate of triplet excitons is improved, the proton transfer process is suppressed, and the non-radiative decay pathway is reduced, thereby obtaining a high-efficiency OLED material based on ESIPT chromophore; on this basis, DPEPO and CBP are selected as single-host materials according to the HOMO and LUMO energy levels of the materials, and CBP and TPBI are selected as dual-host materials to prepare yellow-white light and blue-white light devices, respectively; the efficiency of OLED devices made of the two materials is higher than that of traditional ESIPT fluorescent materials, because the triplet thermal excitons participate in the fluorescence emission process, and there is a significant thermal exciton mechanism in the material, which effectively utilizes the fast reverse intersystem crossing from the high-energy triplet state (T2 and T3) to the S1 state, thereby enhancing the fluorescence emission.

[0027] Beneficial effects:

[0028] 1. This invention proposes a color-tunable "hot exciton" fluorescent material based on high-energy-level reverse intersystem crossing. This color-tunable "hot exciton" fluorescent material has suitable molecular energy levels and high luminescence efficiency, making it suitable for use as a high-efficiency OLED guest dopant material.

[0029] 2. The color-tunable yellow and blue light materials based on "thermoexcitons" described in the present invention are simple to prepare and inexpensive. The OLED devices described herein exhibit high device efficiency and high exciton utilization. The maximum external quantum efficiency of the prepared yellow-white OLED device is 5.33%, and the maximum external quantum efficiency of the prepared blue-white OLED device is 7.54%, both exceeding the theoretical maximum external quantum efficiency of traditional fluorescent OLED devices by 5%.

[0030] 3. The yellow-white OLED device of the present invention gradually changes its emission color from cool white, pure white, and warm white to yellow as the guest concentration increases. Warm white devices have a lower CCT index, making them more physiologically friendly to humans. The CIE coordinates of pure white devices remain stable at (0.33, 0.33), which is the same as the CIE 1931 chromaticity coordinates of white light developed by the International Commission on Illumination. The CRI index reaches 85.1, meeting the CRI ≥ 80 requirement for indoor lighting. The CRI index of cool white devices reaches as high as 90.8, meeting the requirements of special lighting and other fields.

[0031] 4. The blue-white OLED device described herein exhibits dual stability in emission color gamut and device efficiency as guest concentration increases. The device's EL color remains stable within the sky-blue range, with color coordinates varying only from (0.15, 0.25) to (0.15, 0.27). The EQEmax is also highly stable within the range of 7.25-7.54%. Consequently, the device's excellent color and efficiency stability paves the way for large-scale, mass-produced sky-blue OLED devices.

[0032] 5. The color-tunable, high-efficiency OLED device described in the present invention offers new possibilities for display, lighting, and optoelectronic applications due to its ability to achieve a wider range of color representation. It also demonstrates broad application prospects in white light OLEDs, information encryption, and bioengineering.

[0033] 6. The present invention also provides a reference for other related issues in the same field. It can be expanded and extended based on this and applied to other related technical solutions in the field of organic electroluminescence to solve difficult problems in OLED devices such as difficult preparation process, low spectral repeatability and poor color stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 The photoluminescence spectra of Formula I and Formula II mixed with DPEPO at different concentrations in the examples of the present application are shown in Figures a) and b) respectively.

[0035] Figure 21 is a device structure diagram of a dual-body OLED according to an embodiment of the present application. The unit of the figures in the figure is eV. a) is a device structure diagram of a yellow-white light OLED device, and b) is a device structure diagram of a blue-white light OLED device.

[0036] Figure 3 These are electroluminescence spectra of the yellow-white OLED device at different doping concentrations in the embodiment of the present application; a) is 1% doping concentration, b) is 2.5% doping concentration, c) is 10% doping concentration, and d) is 20% doping concentration;

[0037] Figure 4 The electroluminescence spectra of the blue-white OLED device at different doping concentrations in the embodiment of the present application are shown in Figure 1; a) is a 2.5% doping concentration, b) is a 5% doping concentration, c) is a 10% doping concentration, and d) is a 20% doping concentration.

[0038] Figure 5 Performance diagrams of the yellow-white dual-body OLED device in the embodiment of the present application; a) is a current density-voltage-brightness curve, b) is a current efficiency-brightness graph, c) is a power efficiency-brightness graph, and d) is a brightness-external quantum efficiency graph.

[0039] Figure 6 Graphs showing the performance of a blue-white dual-body OLED device according to an embodiment of the present invention include: a) a current density-voltage-brightness graph; b) a current efficiency-brightness graph; c) a power efficiency-brightness graph; and d) a brightness-external quantum efficiency graph.

[0040] Figure 7 For the embodiment of this application, the molecular energy level diagram and spin-orbit coupling coefficient of the yellow-white light and blue-white light materials of the dual-host OLED device in the embodiment of the application are shown in the following examples: a) is the molecular energy level diagram of formula I and its spin-orbit coupling coefficient, and b) is the molecular energy level diagram of formula II and its spin-orbit coupling coefficient;

[0041] Figure 8 The device structure diagrams of the single-body OLED in the embodiments of the present application, the unit of the figures in the figure is eV, a) is the structure diagram of the yellow-white light OLED device, b) is the structure diagram of the blue-white light OLED device;

[0042] Figure 9 Performance diagrams of the yellow-white single-body OLED device in the embodiment of the present application; a) is a current density-voltage-brightness curve, b) is a current efficiency-brightness graph, c) is a power efficiency-brightness graph, and d) is a brightness-external quantum efficiency graph.

[0043] Figure 10 Performance diagrams of the blue-white single-body OLED device in the embodiment of the present application; a) is a current density-voltage-brightness curve, b) is a current efficiency-brightness graph, c) is a power efficiency-brightness graph, and d) is a brightness-external quantum efficiency graph.

[0044] Figure 11 The molecular energy level diagrams and spin-orbit coupling coefficients of the yellow-white light and blue-white light materials of the single-body OLED device in the embodiment of the present application; (a) is the molecular energy level diagram of formula I and its spin-orbit coupling coefficient, and (b) is the molecular energy level diagram of formula II and its spin-orbit coupling coefficient. DETAILED DESCRIPTION

[0045] To more clearly illustrate the technical solution of the present invention, the present invention will be described in detail below with reference to specific embodiments and accompanying drawings. The accompanying drawings only apply to the following embodiments. A person skilled in the art can also obtain other accompanying drawings using the methods described in the present invention. However, the scope of protection of the present invention is not limited to the following embodiments.

[0046] It should be noted that the materials used in this embodiment can be purchased or synthesized using methods known in the art. In the specific examples of this application, the material corresponding to Formula I is denoted as S1, and the material corresponding to Formula II is denoted as S2.

[0047] Application number: CN201910279170, invention name: ESIPT luminescent material with delayed fluorescence properties and its preparation method and application, paragraph

[0050] discloses a method for preparing 2-(benzothiazol-2-yl)-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenol.

[0048] Application number: CN202111524173, invention name: A compound containing hydroxy triarylamine and its application, paragraph

[0151] discloses a method for preparing 2-(benzothiazol-2-yl)-5-(4,4,5,5-tetramethyl-1,3,2-dioxaboran-2-yl)phenol.

[0049] Example 1:

[0050] An excited-state proton transfer OLED material based on a thermal exciton uses 9,9-dimethyl-10-(4-(phenylsulfonyl)phenyl)-9,10-dihydroacridine as a substituent, and is substituted at the para and meta positions of the hydroxyl group through a Suzuki coupling reaction, thereby ultimately preparing two molecules of Formula I and Formula II with different luminescent colors; Formula I is named 2-(benzothiazol-2-yl)-4-(9,9-dimethyl-10-(4-phenylsulfonyl)phenyl)-9,10-dihydroacridine-2-yl)phenol, and Formula II is named 2-benzothiazol-2-yl)-5-(9,9-dimethyl-10-(4-phenylsulfonyl)phenyl)-9,10-dihydroacridine-2-yl)phenol, and their structural formulas are as follows:

[0051]

[0052] The preparation method of the excited state proton transfer OLED material based on thermal excitons, the preparation of 2-(benzothiazol-2-yl)-4-(9,9-dimethyl-10-(4-phenylsulfonyl)phenyl)-9,10-dihydroacridin-2-yl)phenol described in Formula I comprises the following steps:

[0053] Step 1: Take 10g of sodium p-fluorobenzenesulfinate and 26-27g of diphenyltrifluoromethanesulfonic acid iodide, add them to a dry 250mL three-necked flask, connect the condenser, seal the device with a rubber stopper and sealing film, use a double-row tube to evacuate and bubbling nitrogen three times, insert a nitrogen balloon, and then fix the device in an oil bath. Under nitrogen environment, add 120mL of solvent N,N-dimethylformamide DMF and heat at 90℃ for 24 hours; after the reaction is completed, remove the high-boiling point DMF by vacuum distillation, and then add water and dimethylformamide. The product was extracted with chlorine, and the lower organic phase was separated and dried over anhydrous sodium sulfate. The filtered organic solvent was removed, and the crude product was purified by silica gel column, concentrated, and recrystallized from n-hexane to obtain 13-14 g of 1-fluoro-4-phenylsulfonylbenzene as a white solid; the yield was 60-65%; hydrogen spectrum analysis: 1H NMR (400 MHz, Chloroform-d) δ 8.01–7.94 (m, 4H), 7.62–7.50 (m, 3H), 7.23–7.17 (m, 2H);

[0054] Step 2: Take 5g of 9,9-dimethyl-9,10-dihydroacridine and add it to a dry 250mL three-necked flask. Take 4-5g of N-bromosuccinimide and add it to the dropping funnel. Seal the device with a rubber stopper and sealing film. Use a double-row tube to evacuate and bubbling nitrogen three times, and insert a nitrogen balloon. Then place the whole device in an ice-water bath. Add N,N-dimethylformamide DMF to the three-necked flask and dropping funnel respectively. Open the control valve to make the droplets fall. The speed was kept stable. After all the solution in the dropping funnel was dripped, the temperature was raised to room temperature and the reaction was continued for 6 hours. The high-boiling DMF was removed by distillation under reduced pressure. The product was then extracted with water and dichloromethane. The lower organic phase was separated and dried over anhydrous sodium sulfate. The organic solvent was removed by filtration. The crude product was purified by silica gel column to obtain 5-6 g of a dark green solid intermediate 2-bromo-9,9-dimethyl-9,10-dihydroacridine with a yield of 70-75%. Proton spectrum analysis: 1H NMR (400MHz, Chloroform-d) δ7.48(d,J=2.2Hz,1H), 7.39(dd,J=7.8,1.4Hz,1H), 7.22(dd,J=8.4,2.2Hz,1H), 7.14(ddd,J =7.9,7.3,1.4Hz,1H), 6.96(ddd,J=7.8,7.3,1.3Hz,1H), 6.72(dd,J=7.9,1.3Hz,1H), 6.61(d,J=8.5Hz,1H), 1.58(s,6H);

[0055] Step 3: Take 2-bromo-9,9-dimethyl-9,10-dihydroacridine 5-10 g prepared in Step 2, 1-fluoro-4-phenylsulfonylbenzene 1-2 g prepared in Step 1 and sodium hydride, add to a dry 500 mL three-necked flask, connect the condenser tube, seal the device with a rubber plug and sealing film, use double-tube vacuum, nitrogen three times, and insert a nitrogen ball, then fix the device in an oil bath, add 100 mL of solvent N,N-dimethylformamide DMF under nitrogen environment, heat at 100 °C for 12 hours; after the reaction is completed, remove the high-boiling point DMF by distillation under reduced pressure, then extract with water and dichloromethane, separate the lower organic phase, add anhydrous sodium sulfate for drying, remove the organic solvent obtained by filtration, purify the crude product by silica gel column, concentrate and recrystallize with n-hexane, finally obtain 9,9-dimethyl-10-(4-(phenylsulfonyl)phenyl)-9,10-dihydroacridine 10-12 g as light green solid, with a yield of 80-82%; hydrogen spectrum analysis: 1H NMR (400 MHz, Chloroform-d) δ 8.22-8.14 (m, 2H), 8.10-8.03 (m, 1H), 7.95 (ddt, J = 12.5, 7.0, 1.8 Hz, 2H), 7.70-7.64 (m, 1H), 7.63-7.55 (m, 2H), 7.55-7.41 (m, 4H), 7.18 (t, J = 8.6 Hz, 1H), 7.05 (dd, J = 8.8, 2.3 Hz, 1H), 7.01-6.93 (m, 2H), 6.22-6.14 (m, 1H), 6.06 (d, J = 8.8 Hz, 1H), 1.57 (s, 6H);

[0056] Step 4: Take 1-2 g of 9,9-dimethyl-10-(4-(phenylsulfonyl)phenyl)-9,10-dihydroacridine prepared in the third step, 0.3-0.6 g of 2-(benzothiazol-2-yl)-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenol prepared according to the patented method in the ESIPT luminescent material with delayed fluorescence properties and its preparation method and application, and 0.1-0.2 g of tetrakistriphenylphosphine palladium Pd(Phh3)4 are added to a dry 50 mL Schlenk reaction tube, vacuum and nitrogen are blown three times using a double-row tube, 20 mL of a solvent mixed with tetrahydrofuran and toluene in a volume ratio of 1:1 is added, and then 2.5 mL of a 2 mol / L mixed solution of potassium carbonate and potassium fluoride dissolved in deionized water is added, wherein potassium carbonate K2CO3 680-690 mg and potassium fluoride KF 290-300 mg; the reaction apparatus was then fixed in an oil bath and heated at 90° C. for 24 hours. After the reaction was completed, the solvent was distilled off under reduced pressure, and then extracted with water and dichloromethane. The lower organic phase was separated and dried over anhydrous sodium sulfate. The organic solvent obtained by filtration was removed, and the crude product was purified by silica gel column, concentrated, and recrystallized from n-hexane to finally obtain 0.1-0.3 g of a light yellow solid material of formula I with a yield of 30-35%; hydrogen spectrum analysis: 1HNMR (400 MHz, DMSO-d6) δ 11.61 (s, 1H), 8.32 (d, J = 2.3 Hz, 1H), 8.25 (d, J = 8.3 Hz, 2H), 8.14 (d, J = 7.9 Hz, 1H), 8.08 (t ,J=7.8Hz,3H), 7.79–7.66(m,8H), 7.54(ddt,J=6.0,4.2,2.0Hz,2H), 7.45 (t, J=7.6Hz, 1H), 7.31 (dd, J=8.6, 2.1Hz, 1H), 7.15 (d, J=8.6Hz, 1H), 7.04 –6.94(m,3H), 6.26(d,J=8.5Hz,1H), 6.18(dd,J=7.9,1.5Hz,1H), 1.69(s,6H).MALDI-TOFm / z:649.7[M]+.HRMS(EI)m / z:651.1777[M]+.Anal.Calcd for C 40 H 30 N2O3S2(651.1771), the reaction formula is:

[0057]

[0058] The preparation method of the excited state proton transfer OLED material based on thermal excitons, the preparation of 2-benzothiazol-2-yl)-5-(9,9-dimethyl-10-(4-phenylsulfonyl)phenyl)-9,10-dihydroacridin-2-yl)phenol described in Formula II comprises the following steps:

[0059] Step 1: Take 1-2 g of 9,9-dimethyl-10-(4-(phenylsulfonyl)phenyl)-9,10-dihydroacridine, 0.5-1 g of 2-(benzothiazol-2-yl)-5-(4,4,5,5-tetramethyl-1,3,2-dioxaboran-2-yl)phenol prepared according to a patented method for a compound containing a hydroxyl triarylamine and its application, and 0.1-0.3 g of tetrakistriphenylphosphine palladium Pd(Phh3)4 and add them to 50 mL of dry In a Schlenk reaction tube, 20 mL of a solvent mixed with tetrahydrofuran and toluene in a volume ratio of 1:1 was added, and then 5 mL of a 2 mol / L mixed solution of potassium carbonate K2CO3 and potassium fluoride KF dissolved in deionized water was added, wherein 1.3-1.4 g of potassium carbonate K2CO3 and 580-590 mg of potassium fluoride KF were added. The reaction device was then fixed in an oil bath and heated at 90°C for 24 hours. After the reaction was completed, the solvent was distilled off under reduced pressure, and then extracted with water and dichloromethane. The lower organic phase was separated and dried over anhydrous sodium sulfate. The organic solvent obtained by filtration was removed, and the crude product was purified by silica gel column, concentrated, and recrystallized with n-hexane to finally obtain 0.2-0.4 g of a light yellow solid material of formula II with a yield of 25-30%; hydrogen spectrum analysis 1HNMR (400MH z,DMSO-d6)δ8.27(d,J=8.4Hz,3H), 8.11(ddd,J=32.5,16.8,8.4Hz,7H), 7.82( d,J=2.1Hz,1H), 7.77(d,J=7.3Hz,1H), 7.70(t,J=8.7Hz,4H), 7.55(d,J=7.5Hz ,2H), 7.44(t,J=7.6Hz,2H), 7.36(d,J=8.6Hz,1H), 7.30(d,J=5.1Hz,2H), 7.04 –6.93(m,3H),6.21(d,J=8.6Hz,2H),6.14–6.10(m,1H),1.70(s,6H).MALDI-TOF m / z:649.2[M]+.HRMS(EI)m / z:651.1779[M]+.Anal.Calcd for C 40 H 30 N2O3S2(651.1771); the reaction formula is:

[0060]

[0061] Formula I, Formula II, and bis[2-((oxy)diphenylphosphino)phenyl]ether (DPEPO) were mixed in different concentration ratios to prepare a light-emitting film. The specific steps are as follows:

[0062] Step 1: Take DPEPO;

[0063] Step 2: Take Formula I. The concentration ratio of Formula I to DPEPO should be DPEPO: 0.5%, 1%, 2.5%, 15%, 20% Formula I;

[0064] Step 3: Take Formula II. The concentration ratio of Formula II to DPEPO should be DPEPO: 1%, 2.5%, 20% Formula II;

[0065] Step 4: Dissolve the compounds of formula I, formula II and DPEPO in dichloromethane solution;

[0066] Step 5: Use a rubber-tipped dropper to drop the dissolved solution onto a quartz wafer to prepare a thin film.

[0067] like Figure 1 The luminescence spectrum was measured between excitation wavelengths of 380 nm and 700 nm. It can be seen that the luminescence wavelength changed with the change in the concentration of Formula I and Formula II, that is, the concentration change can obtain solid-state luminescent films with different luminescence colors.

[0068] Example 2

[0069] The application of excited state proton transfer OLED materials based on thermal excitons in solid-state light-emitting films and OLED devices, the OLED device includes an organic light-emitting layer, the material of the organic light-emitting layer is a yellow and blue fluorescent material with high exciton utilization rate doped with main materials CBP and TPBi; the OLED device is a multi-layer structure stacked up and down, from bottom to top, it is an ITO substrate, an anode layer, a hole injection layer, a hole transport layer, an electron blocking layer, an organic light-emitting layer, a hole blocking layer, an electron injection layer, and a cathode layer; the material of the anode layer is an inorganic material, the inorganic material is indium tin oxide or indium zinc oxide; the material of the hole injection layer is MoO3; the thickness of the hole injection layer is 2nm; the material of the hole transport layer is TAPC; the thickness of the hole transport layer is 4 0nm; the material of the electron blocking layer is TCTA; the thickness of the electron blocking layer is 10nm; the material of the organic light-emitting layer is a doping of the main materials CBP and TPBi with materials of formula I and formula II having high exciton utilization; the thickness of the organic light-emitting layer is 30nm; the doping concentration of the organic light-emitting layer formula I is 1%, 2.5%, 10%, and 20%; the doping concentration of the organic light-emitting layer formula II is 2.5%, 5%, 10%, and 20%; the material of the hole blocking layer is TPBi; the thickness of the hole blocking layer is 50nm; the material of the electron injection layer is LiF; the thickness of the electron injection layer is 0.5-1nm; the material of the cathode layer is any one of gold, silver, copper, aluminum, and magnesium; the thickness of the cathode layer is 100nm.

[0070] The specific production process of this embodiment is as follows:

[0071] Step 1: Clean the ITO (indium tin oxide) glass by ultrasonically cleaning it with acetone, water, and ethanol for 15 minutes each, and then drying it in an oven for 2 hours;

[0072] Step 2: Plasma treat the oven-dried ITO indium tin oxide glass for 50 seconds;

[0073] Step 3: vacuum evaporate the hole transport layer TAPC on the anode layer on the ITO substrate at a rate of 2 Hz / s and a film thickness of 40 nm;

[0074] Step 4: Vacuum evaporate the electron blocking layer TCTA on the hole transport layer at a rate of 2 Hz / s and a film thickness of 10 nm;

[0075] Step 5: Evaporate an organic light-emitting layer CBP:TPBi: Formula I (Formula II) on the electron blocking layer at a rate of 2 Hz / s and a film thickness of 30 nm;

[0076] Step 6: On top of the organic light-emitting layer, TPBI as a hole blocking layer was vacuum-deposited at a rate of 2 Hz / s and a film thickness of 50 nm.

[0077] Step 8: On the electron transport layer, LiF as the electron injection layer is vacuum evaporated at a rate of 0.1 Hz / s and a thickness of 0.7 nm.

[0078] Step 9: On top of the electron injection layer, vacuum evaporate the cathode layer Al with a thickness of 100 nm.

[0079] The device structure of the dual-host OLED device in this embodiment is ITO / TAPC / TCTA / CBP:TPBi:Formula I (Formula II) / TPBI / LiF / Al, as shown in FIG. Figure 2 As shown. During the vacuum evaporation process, the pressure is less than 1.0×10 -3 Pa, wherein the compounds 2-(benzothiazol-2-yl)-4-(9,9-dimethyl-10-(4-phenylsulfonyl)phenyl)-9,10-dihydroacridin-2-yl)phenol (S1) and 2-benzothiazol-2-yl)-5-(9,9-dimethyl-10-(4-phenylsulfonyl)phenyl)-9,10-dihydroacridin-2-yl)phenol (S2) are used as the light-emitting materials of the device.

[0080] The device was tested for OLED properties. The maximum brightness of the S1 device was 4110 cd / m 2 The maximum current efficiency is 14.32cd / A, the maximum power efficiency is 14.73lm / W, and the maximum external quantum efficiency is 5.54%. The maximum brightness of the S2 device is 9223cd / m 2 The maximum current efficiency is 14.59cd / A, the maximum power efficiency is 15.01lm / W, and the maximum external quantum efficiency is 7.40%. Figure 3 It can be seen that the EL spectra of the four devices of S1 material show dual emission of the enol form at around 480nm and the keto form at around 570nm. In addition, as the voltage increases, the emission ratio of the EL enol form relative to the keto form gradually increases at low doping concentration (1%), while the emission ratio of the EL enol form and the keto form remains basically unchanged at high doping concentration. Figure 4 It can be seen that the EL spectra of the four devices with S2 material have always stably shown an emission peak of the combined enol and keto forms around 465nm. As the voltage increases from 4V to 12V, the emission peak remains stable. The fluorescence quantum efficiency of the devices was measured and the fluorescence quantum efficiency of S1 and S2 was 14.58% and 24.71%, respectively. The formula η r =EQE max / (γ×η PL ×η out) The calculated exciton utilization of the device is 74 and 88%. The molecular energy level diagrams of S1 and S2 are calculated. The energy level differences between S1 and T2, T3, T4 and T5 are very small, 0.152, 0.015, 0.086 and 0.211 eV respectively. The corresponding spin-orbit coupling (SOC) matrix element values ​​are and They are 0.684, 0.135, 0.082 and 0.464 cm respectively -1 The energy level differences between S2 and T6 and T7 are as low as 0.011 and 0.054 eV respectively. and 1.044 and 1.230 cm respectively -1 The energy levels of S3, T8 and T9 are also very close, with energy level differences of 0.076 and 0.031 eV respectively. The SOC matrix element values ​​are and are 0.091 and 0.954 cm respectively. -1 The ΔEST(S4, T10) between S4 and T10 is 0.021eV. 0.077cm -1 In addition, due to the large energy gap between T2 and T1 (0.241 eV), the internal conversion (IC) process from T2 to T1 is greatly suppressed. Therefore, according to the energy gap and SOC value, the reverse intersystem crossing from the high-energy triplet state to the singlet state becomes the dominant process. The experimental results are as follows Figure 5-Figure 7 shown.

[0081] Example 3

[0082] The application of excited state proton transfer OLED materials based on thermal excitons in solid-state light-emitting films and OLED devices, the OLED device includes an organic light-emitting layer, the material of the organic light-emitting layer is a fluorescent material with high exciton utilization rate doped with the main material DPEPO; the OLED device is a multi-layer structure single-body OLED device stacked up and down, from bottom to top, it includes an ITO substrate, an anode layer, a hole injection layer, a hole transport layer, an electron blocking layer, an organic light-emitting layer, a hole blocking layer, an electron injection layer, and a cathode layer; the material of the anode layer is an inorganic material, the inorganic material is indium tin oxide or indium zinc oxide; the material of the hole injection layer is MoO3; the thickness of the hole injection layer is 1-2nm; the material of the hole transport layer is mcp or TAPC ; The thickness of the hole transport layer is 40-50nm; the material of the electron blocking layer is TCTA; the thickness of the electron blocking layer is 10-20nm; the material of the organic light-emitting layer is the main material DPEPO or CBP doped with materials of formula I and formula II with high exciton utilization rate; the thickness of the organic light-emitting layer is 30-40nm; the doping concentration of the organic light-emitting layer is 0.5%-20%; the material of the hole blocking layer is TPBi or TmPyPB; the thickness of the hole blocking layer is 50-60nm; the material of the electron injection layer is LiF; the thickness of the electron injection layer is 0.5-1nm; the material of the cathode layer is any one of gold, silver, copper, aluminum, and magnesium; the thickness of the cathode layer is 100nm.

[0083] The specific production process of this embodiment is as follows:

[0084] Step 1: Clean the ITO indium tin oxide glass by ultrasonically cleaning it with acetone, water, and ethanol for 15 minutes each, and then drying it in an oven for 2 hours;

[0085] Step 2: Plasma treat the oven-dried ITO indium tin oxide glass for 50 seconds;

[0086] Step 3: vacuum evaporate the hole transport layer MCP on the anode layer on the ITO substrate at a rate of 2 Hz / s and a film thickness of 40-50 nm;

[0087] Step 4: Evaporate the organic light-emitting layer DPEPO:S1 (S2) on the electron blocking layer at a rate of 2 Hz / s and a film thickness of 30-40 nm;

[0088] Step 5: On top of the organic light-emitting layer, TPBI is vacuum-deposited as a hole-blocking layer at a rate of 2 Hz / s with a film thickness of 50-60 nm.

[0089] Step 6: On the electron transport layer, vacuum evaporate LiF as the electron injection layer at a rate of 0.1 Hz / s and a thickness of 1-2 nm;

[0090] Step 7: On top of the electron injection layer, vacuum evaporate the cathode layer Al with a thickness of 100 nm.

[0091] The device structure of the single-body OLED device in this embodiment is ITO / mcp / DPEPO:S1(S2) / TPBI / LiF / Al. Figure 8 As shown. During the vacuum evaporation process, the pressure is less than 1.0×10 -3 Pa, wherein the compounds 2-(benzothiazol-2-yl)-4-(9,9-dimethyl-10-(4-phenylsulfonyl)phenyl)-9,10-dihydroacridin-2-yl)phenol (S1) and 2-benzothiazol-2-yl)-5-(9,9-dimethyl-10-(4-phenylsulfonyl)phenyl)-9,10-dihydroacridin-2-yl)phenol (S2) are used as the light-emitting materials of the device.

[0092] The device was tested for OLED properties. The maximum brightness of the S1 device was 1503cd / m 2 The maximum current efficiency is 2.19cd / A, the maximum power efficiency is 1.60lm / W, and the maximum external quantum efficiency is 1.82%. The maximum brightness of the S2 device is 3414cd / m 2 The maximum current efficiency is 5.42cd / A, the maximum power efficiency is 5.10lm / W, and the maximum external quantum efficiency is 2.84%. The fluorescence quantum efficiencies of S1 and S2 are measured to be 14.58% and 24.71%, respectively, and are calculated by the formula η r =EQE max / (γ×η PL ×η out ) The calculated exciton utilization of the device is 57% and 62%. The molecular energy level diagram of S1 is calculated. The S1 energy level of the S1 keto form is very close to the T2 and T3 energy levels. The energy gap between S1 and T2 is 0.01eV, and the energy gap between S1 and T3 is 0.035eV. However, the spin-orbit coupling matrix coefficient between S1 and T3 is 0.385cm -1 , is much larger than the spin-orbit coupling matrix coefficient between S1 and T2, so the reverse intersystem crossing mainly occurs between S1 and T3. At the same time, the large energy difference between T2 and T1 suppresses the internal conversion efficiency and promotes the reverse intersystem crossing rate. Calculating the molecular energy level diagram of S2, the spin-orbit coupling matrix coefficient between S1 and T3 is much larger than the spin-orbit coupling matrix coefficient between S1 and T2, indicating that reverse intersystem crossing from high energy level to low energy level can occur from T3 to S1, which is beneficial to the emission of alcohol. The experimental results are as follows Figures 9-11 shown.

[0093] This invention proposes a color-tunable "hot exciton" fluorescent material based on high-energy-level reverse intersystem crossing. This color-tunable "hot exciton" fluorescent material exhibits suitable molecular energy levels and high luminescence efficiency, making it suitable for use as a high-efficiency guest dopant material in organic light-emitting diodes (OLEDs). This invention also provides a reference for other related issues in the field and can be expanded upon and applied to other related technical solutions in the field of organic electroluminescence, addressing challenges such as difficult fabrication processes, low spectral repeatability, and poor color stability in OLED devices.

[0094] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. Excited state proton transfer OLED material based on thermal excitons, characterized by: The excited state proton transfer OLED material based on thermal excitons uses 9,9-dimethyl-10-(4-(phenylsulfonyl)phenyl)-9,10-dihydroacridine as a substituent, and is substituted at the para and meta positions of the hydroxyl group through a Suzuki coupling reaction, thereby finally preparing two molecules of formula I and formula II with different luminescent colors; the name of formula I is 2-(benzothiazol-2-yl)-4-(9,9-dimethyl-10-(4-phenylsulfonyl)phenyl)-9,10-dihydroacridine-2-yl)phenol, and the name of formula II is 2-benzothiazol-2-yl)-5-(9,9-dimethyl-10-(4-phenylsulfonyl)phenyl)-9,10-dihydroacridine-2-yl)phenol, and the structural formulas are as follows:

2. A method for preparing the excited state proton transfer OLED material based on thermal excitons according to claim 1, characterized in that: The preparation of 2-(benzothiazol-2-yl)-4-(9,9-dimethyl-10-(4-phenylsulfonyl)phenyl)-9,10-dihydroacridin-2-yl)phenol of formula I comprises the following steps: Step 1: Take 10g of sodium p-fluorobenzenesulfinate and 26-27g of diphenyltrifluoromethanesulfonic acid iodide, add them to a dry 250mL three-necked flask, connect the condenser, seal the device with a rubber stopper and sealing film, use a double-row tube to evacuate and purge with nitrogen three times, and insert a nitrogen balloon, then fix the device in an oil bath pot, add 120mL of solvent N,N-dimethylformamide DMF under a nitrogen environment, and heat at 90°C for 24 hours; after the reaction is completed, remove the high-boiling point DMF by reduced pressure distillation, then extract with water and dichloromethane, separate the lower organic phase, add anhydrous sodium sulfate to dry, remove the filtered organic solvent, purify the crude product by silica gel column, concentrate and recrystallize with n-hexane to finally obtain white solid 1-fluoro-4-phenylsulfonylbenzene; Step 2: Take 5g of 9,9-dimethyl-9,10-dihydroacridine and add it to a dry 250mL three-necked flask, take 4-5g of N-bromosuccinimide and add it to the dropping funnel, seal the device with a rubber stopper and a sealing film, use a double-row tube to evacuate and blow nitrogen three times, and insert a nitrogen balloon, then place the entire device in an ice-water bath, add N,N-dimethylformamide DMF to the three-necked flask and the dropping funnel respectively, open the control valve so that the falling speed of the droplet remains stable, after the solution in the dropping funnel is completely dripped, heat to room temperature and react for 6 hours, remove the high-boiling DMF by reduced pressure distillation, then extract with water and dichloromethane, separate the lower organic phase, add anhydrous sodium sulfate to dry, remove the organic solvent obtained by filtration, and purify the crude product by silica gel column to finally obtain a dark green solid intermediate 2-bromo-9,9-dimethyl-9,10-dihydroacridine; Step 3: Take 5-10 g of 2-bromo-9,9-dimethyl-9,10-dihydroacridine prepared in the second step, 1-2 g of 1-fluoro-4-phenylsulfonylbenzene prepared in the first step and sodium hydride, add them to a dry 500 mL three-necked flask, connect the condenser, seal the device with a rubber stopper and sealing film, use a double-row tube to evacuate and bubbling nitrogen three times, insert a nitrogen balloon, and then fix the device in an oil bath. Under nitrogen environment, add 100 mL The solvent N,N-dimethylformamide (DMF) was heated at 100°C for 12 hours. After the reaction was completed, the high-boiling DMF was removed by distillation under reduced pressure, and then the mixture was extracted with water and dichloromethane. The lower organic phase was separated and dried over anhydrous sodium sulfate. The organic solvent was removed by filtration. The crude product was purified by silica gel column, concentrated, and recrystallized from n-hexane to obtain a light green solid 9,9-dimethyl-10-(4-(phenylsulfonyl)phenyl)-9,10-dihydroacridine. Step 4: Take 1-2 g of 9,9-dimethyl-10-(4-(phenylsulfonyl)phenyl)-9,10-dihydroacridine prepared in step 3, 0.3-0.6 g of 2-(benzothiazol-2-yl)-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenol, and 0.1-0.2 g of tetrakistriphenylphosphine palladium Pd(Phh3)4 and add them to 50 mL of dry In a Schlenk reaction tube, vacuum and nitrogen were purged three times using a double-row tube, and 20 mL of a solvent mixed with tetrahydrofuran and toluene in a volume ratio of 1:1 was added, followed by 2.5 mL of a 2 mol / L mixed solution of potassium carbonate and potassium fluoride dissolved in deionized water, wherein 680-690 mg of potassium carbonate K2CO3 and 290-300 mg of potassium fluoride KF were added; the reaction apparatus was then fixed in an oil bath and heated at 90°C for 24 hours. After the reaction was completed, the solvent was removed by distillation under reduced pressure, and then extracted with water and dichloromethane to separate the lower organic phase, which was dried over anhydrous sodium sulfate. The organic solvent obtained by filtration was removed, and the crude product was purified by silica gel column, concentrated, and recrystallized with n-hexane to finally obtain a light yellow solid material of formula I, with the reaction formula being:

3. The method for preparing an excited state proton transfer OLED material based on thermal excitons according to claim 2, characterized in that: The preparation of 2-benzothiazol-2-yl)-5-(9,9-dimethyl-10-(4-phenylsulfonyl)phenyl)-9,10-dihydroacridin-2-yl)phenol of formula II comprises the following steps: Step 1: Take 1-2 g of 9,9-dimethyl-10-(4-(phenylsulfonyl)phenyl)-9,10-dihydroacridine, 0.5-1 g of 2-(benzothiazol-2-yl)-5-(4,4,5,5-tetramethyl-1,3,2-dioxaboran-2-yl)phenol, and 0.1-0.3 g of tetrakistriphenylphosphine palladium Pd(Phh3)4, add them into a dry 50 mL Schlenk reaction tube, add 20 mL of a solvent mixed with tetrahydrofuran and toluene in a volume ratio of 1:1, and then add 5 mL of a 2 mol / L mixed solution of potassium carbonate K2CO3 and potassium fluoride KF dissolved in deionized water, wherein potassium carbonate K2CO3 1.3-1.4 g, potassium fluoride KF The reaction apparatus was then fixed in an oil bath and heated at 90°C for 24 hours. After the reaction was completed, the solvent was distilled off under reduced pressure, and then extracted with water and dichloromethane. The lower organic phase was separated and dried over anhydrous sodium sulfate. The organic solvent was removed by filtration, and the crude product was purified by silica gel column, concentrated, and recrystallized with n-hexane to obtain a light yellow solid material of formula II. The reaction formula is:

4. Use of the excited state proton transfer OLED material based on thermal excitons according to claim 1 in a solid-state light-emitting film and an OLED device, characterized in that: By changing the position and concentration of substituents, solid-state light-emitting films and OLED devices with different luminous colors, such as blue light, cool white light, white light, warm white light or yellow light, are obtained. The solid-state light-emitting films and OLED devices use DPEPO as a single host material or CBP and TPBi as a dual host material. The solid-state film of Formula I exhibits yellow light, and the solid-state film of Formula II exhibits blue light.

5. The use of the excited state proton transfer OLED material based on thermal excitons in solid-state light-emitting thin films and OLED devices according to claim 4, characterized in that: As the doping concentration of the formula I material increases from 0.5%, 1%, 2.5%, and 20%, the luminescent color of its solid-state film and its OLED device gradually changes from cool white, pure white, and warm white to yellow; the EQEmax, CIE, and CCT indices of the warm white light, pure white light, and cool white light devices are 5.33%, (0.41, 40), 3361K, 4.00%, (0.33, 33), 5096K, and 4.00%, (0.31, 0.32), 6886K, respectively. Among them, the CRI indices of the pure white light and cool white light devices are 85.1 and 90.

8.

6. The use of the excited state proton transfer OLED material based on thermal excitons in solid-state light-emitting thin films and OLED devices according to claim 4, characterized in that: As the doping concentration of the material of formula II increases by 2.5% to 20%, the luminous color of the device remains stable in the sky blue range, the color coordinate variation range is (Δ±0.005, Δ±0.01), and the EQEmax is stable in the range of 7.25 to 7.54%.

7. The use of the excited state proton transfer OLED material based on thermal excitons in solid-state light-emitting thin films and OLED devices according to claim 4, characterized in that: Formula I and Formula II achieve efficient utilization of excitons through reverse intersystem crossing. Their single-host OLED devices can achieve an exciton utilization rate of 55% to 65%, and their dual-host OLED devices can achieve an exciton utilization rate of 73% to 88%.

8. Use of the excited state proton transfer OLED material based on thermal excitons according to claim 4 in solid-state light-emitting thin films and OLED devices, characterized in that: The OLED device is a double-body OLED device with a multi-layer structure stacked up and down, which includes, from bottom to top, an ITO substrate, an anode layer, a hole injection layer, a hole transport layer, an electron blocking layer, an organic light-emitting layer, a hole blocking layer, an electron injection layer, and a cathode layer; the material of the anode layer is an inorganic material, which is indium tin oxide or indium zinc oxide; the material of the hole injection layer is MoO3; the thickness of the hole injection layer is 1-2 nm; the material of the hole transport layer is TAPC; the thickness of the hole transport layer is 40-50 nm; the material of the electron blocking layer is TCTA; the electron blocking layer is 1-2 nm; ... hole transport layer is 40-50 nm; the hole transport layer is 1-2 nm; the hole transport layer is 1-2 nm; the hole transport layer is 1-2 nm; the hole transport layer is 1-2 nm; the hole transport layer is 1-2 nm; the hole transport layer is 1-2 nm; the hole injection layer is 1-2 nm; the hole transport layer is 1-2 nm; the hole transport layer is 40-50 nm; the electron blocking layer is 1-2 nm; the hole injection layer is 1-2 nm; the hole transport layer is 1-2 nm; the hole transport layer is 1-2 nm; the hole transport layer is 40-50 nm; the hole injection layer is 1-2 nm; the hole transport layer is 1-2 nm; the hole transport layer is 40-50 nm; the hole injection layer is 1-2 nm; the hole transport layer is 40-50 nm; the hole injection layer is 1-2 nm; the hole transport layer is 40-50 nm; the hole injection layer is 1-2 nm; the hole transport layer is 40 The thickness of the layer is 10-20 nm; the material of the organic light-emitting layer is a doping of the main materials CBP and TPBi with materials of formula I and formula II having high exciton utilization rate; the thickness of the organic light-emitting layer is 30-40 nm; the doping concentration of the organic light-emitting layer is 0.5%-20%; the material of the hole blocking layer is TPBi; the thickness of the hole blocking layer is 50-60 nm; the material of the electron injection layer is LiF; the thickness of the electron injection layer is 0.5-1 nm; the material of the cathode layer is any one of gold, silver, copper, aluminum, and magnesium; and the thickness of the cathode layer is 100 nm.

9. Use of the excited state proton transfer OLED material based on thermal excitons according to claim 4 in solid-state light-emitting thin films and OLED devices, characterized in that: The OLED device is a multi-layered single-body OLED device stacked up and down, which includes, from bottom to top, an ITO substrate, an anode layer, a hole injection layer, a hole transport layer, an electron blocking layer, an organic light-emitting layer, a hole blocking layer, an electron injection layer, and a cathode layer; the material of the anode layer is an inorganic material, which is indium tin oxide or indium zinc oxide; the material of the hole injection layer is MoO3; the thickness of the hole injection layer is 1-2nm; the material of the hole transport layer is mcp or TAPC; the thickness of the hole transport layer is 40-50nm; the material of the electron blocking layer is TCTA; the electron blocking layer The thickness is 10-20nm; the material of the organic light-emitting layer is a doping of the main material DPEPO or CBP and the materials with high exciton utilization rate of formula I and formula II; the thickness of the organic light-emitting layer is 30-40nm; the doping concentration of the organic light-emitting layer is 0.5%-20%; the material of the hole blocking layer is TPBi or TmPyPB; the thickness of the hole blocking layer is 50-60nm; the material of the electron injection layer is LiF; the thickness of the electron injection layer is 0.5-1nm; the material of the cathode layer is any one of gold, silver, copper, aluminum, and magnesium; the thickness of the cathode layer is 100nm.

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