A blue fluorescent material with exciton cycle and hot exciton properties, and a preparation method and application thereof

Abstract

This invention discloses a blue fluorescent material with exciton cycling and thermal exciton properties, its preparation method, and its applications, belonging to the field of organic electroluminescent materials technology. The material is named diphenyl(6-(4-(triphenylsilyl)phenyl)pyrene-1-yl)phosphine oxide (P-TPSPyPO) or diphenyl(6-(3-(triphenylsilyl)phenyl)pyrene-1-yl)phosphine oxide (M-TPSPyPO). This invention solves the problems of easy fluorescence quenching of small organic molecules under high-temperature conditions, complex fabrication processes, high costs, poor stability, difficulty in operating at high temperatures, and application in single-molecule blue OLED device luminescent materials.

Description

Technical Field

[0001] This invention belongs to the field of organic electroluminescent materials technology, specifically relating to a blue fluorescent material with exciton cycling and thermal exciton properties, its preparation method, and its application. Background Technology

[0002] Luminescent materials have accompanied the entire course of human civilization's development. Based on their chemical composition and luminescence mechanism, they can be mainly divided into two categories: organic and inorganic systems. The photophysical process of organic luminescent materials is essentially the photon emission phenomenon caused by the return of molecules from the excited state to the ground state via radiative transitions after being excited. In today's information age, organic luminescent materials have been widely used in cutting-edge technology fields such as optical communication, flat panel display technology, laser devices, and biomolecular probes, significantly promoting the technological progress of related industries and the development of social civilization.

[0003] Temperature threshold indication and temperature sensing in high-temperature regions are crucial in numerous modern industrial and scientific fields, encompassing industrial automation, security alarm systems, aerospace, electronic skin, fluid dynamics, biomedicine, and information encryption and anti-counterfeiting. These two functions meet different needs: temperature threshold indicators record thermal history, while temperature sensors enable real-time in-situ thermal monitoring. Traditional sensors such as thermocouples and thermistors, while reliable and inexpensive, are inherently limited by spatial resolution. Furthermore, constructing sensor arrays for large-area imaging is often prohibitively expensive, making them unsuitable for large or flexible surfaces. Meanwhile, while infrared thermal imaging is non-contact, it is susceptible to environmental interference (such as reflectors, dust, and haze), resulting in low image contrast and limited temperature resolution, and poor performance on smooth surfaces. In contrast, emission signals, as one of the most sensitive and easily observable detection parameters, encompass multiple detectable dimensions in their fluorescence response, including luminescence intensity, spectral shift, excited-state lifetime, and fluorescence quantum efficiency. Fluorescent temperature sensors based on luminescent materials exhibit significant advantages in the aforementioned aspects: simple operation, high intrinsic safety, excellent spatial resolution, low power consumption, and fast response speed, while also possessing high temperature sensitivity and high-resolution testing performance. Based on this, such sensors have been widely used for precise detection ranging from complex geometric solid surfaces to microscopic intracellular temperature fields. However, the luminescence of organic luminescent materials is prone to thermal quenching at high temperatures, making the development of suitable organic materials for high-temperature luminescence a pressing issue.

[0004] Organic light-emitting diodes (OLEDs), as an emerging display and lighting technology, operate on the principle that electrons and holes injected from the cathode and anode, respectively, recombine in the organic light-emitting layer under an applied electric field to form excitons, which then emit light through exciton deexcitation radiation. Compared to traditional display technologies, OLEDs exhibit significant advantages in display and lighting due to their self-emissive nature, thin and lightweight structure, high contrast, fast response, wide viewing angle, and flexibility. Currently, this technology has been widely adopted in high-end smartphones, televisions, virtual reality devices, and automotive interiors, while its surface light source characteristics have enabled innovative applications such as interior lighting and signage lighting in the lighting field.

[0005] With the rapid expansion of fields such as energy, automotive, aerospace, electronic skin, and marine exploration, organic light-emitting materials suitable for high-temperature environments have gradually become key candidate materials in high-temperature sensing and related information reading technologies. In these high-end application scenarios, organic light-emitting diodes (OLEDs) have shown unique advantages in realizing interactive and real-time information visualization due to their excellent color rendering performance, low-cost fabrication process, and low energy consumption. Unique photophysical processes related to heat in organic light-emitting materials, such as thermally activated delayed fluorescence (TADF) and "thermal excitons," have become hot research topics in OLEDs. The key to "thermal exciton" light-emitting materials lies in their ability to utilize rapid reverse intergap crossing (hRISC) from the high-level triplet excited state (Tn, n>1) to a singlet excited state with similar energy. This process strongly competes with the internal conversion (IC) from Tn to the lowest triplet state (T1). In this way, all excitons generated by electrical excitation can be effectively utilized, thereby achieving a theoretically high singlet exciton utilization rate of up to 100%. Thermal excitons are one way to effectively utilize triplet excitons, while the increase in singlet excitons promises to exhibit high brightness and efficiency at high temperatures. Meanwhile, fast hRISC can effectively suppress the accumulation of triplet excitons as current density increases, thus avoiding triplet-related annihilation processes and enabling OLED devices to maintain low efficiency degradation while operating at high efficiency. From this perspective, these organic materials may show great potential in high-temperature sensing and OLED devices.

[0006] Based on the above discussion, we envision that materials with exciton cycling and "thermal exciton" properties can be introduced into temperature sensor and OLED device applications to prepare low-cost, efficient, stable, easy-to-fabricate, and highly repeatable high-performance temperature sensors and OLED devices. Summary of the Invention

[0007] Technical problems to be solved: In view of the above-mentioned technical problems, the present invention provides a blue fluorescent material with exciton cycle and thermal exciton properties, its preparation method and application, so as to solve the problems of fluorescence quenching of organic small molecules under high temperature conditions, complex manufacturing process, high cost and poor stability in the prior art, difficulty in working at high temperature, and application in single-molecule blue OLED device luminescent materials.

[0008] Technical solution: A blue fluorescent material with exciton cycling and thermal exciton properties, P-TPSPyPO or M-TPSPyPO, with the following structural formulas:

[0009] , .

[0010] Preferably, the blue fluorescent material exhibits fluorescence heat resistance under both solution and thin film conditions.

[0011] A method for preparing a blue fluorescent material with exciton cycling and thermal exciton properties includes the following steps:

[0012] Step 1: Mix the intermediate (4-(6-bromopyrene-1-yl)phenyl)triphenylsilane or (3-(6-bromopyrene-1-yl)phenyl)triphenylsilane with diphenylphosphine oxide, palladium acetate, 1,1'-bis(diphenylphosphine)ferrocene and cesium carbonate to obtain a mixture;

[0013] Step 2: Inject anhydrous N,N-dimethylformamide solvent into the mixture under nitrogen atmosphere and heat to reflux for reaction;

[0014] Step 3: After the reaction, the solvent is removed by vacuum distillation, and the lower organic phase is obtained by extraction and separation. Anhydrous sodium sulfate is added for drying, and after rotary drying, silica gel powder is added. A mixed solvent of petroleum ether and ethyl acetate is used as the eluent. After column chromatography, the white solid is obtained by rotary drying. Then, after recrystallization and vacuum drying, the blue fluorescent material is obtained.

[0015] Preferably, the intermediate is prepared as follows: Triphenyl(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborhexacyclopentan-2-yl)phenyl)silane or triphenyl(3-(4,4,5,5-tetramethyl-1,3,2-dioxaborhexacyclopentan-2-yl)phenyl)silane is mixed with 1,6-dibromopyrene, tetra(triphenylphosphine)palladium, potassium fluoride, and potassium carbonate. Toluene, tetrahydrofuran, and water are added under nitrogen atmosphere, and the mixture is heated under reflux. After the reaction is complete, the lower organic phase is extracted and separated. Anhydrous sodium sulfate is added for drying, and after rotary drying, silica gel powder is added. A mixed solvent of petroleum ether and dichloromethane is used as the eluent. After column chromatography, the solid is rotary dried to obtain a white solid. The solid is then recrystallized and vacuum dried to obtain the intermediate.

[0016] Preferably, the volume ratio of petroleum ether to ethyl acetate in the eluent is 1:3; the recrystallization uses a solution of dichloromethane and n-hexane as the solvent; and the vacuum drying temperature is 60°C and the time is 24 hours.

[0017] The above-mentioned blue fluorescent material with exciton cycling and thermal exciton properties is used in threshold temperature indication, wherein the blue fluorescent material exists in the form of a thin film and exhibits a threshold temperature response at 120°C.

[0018] Preferably, when the blue fluorescent material is P-TPSPyPO, from 20℃ to 120℃, the color abruptly changes from cyan to sky blue, and the coordinates on the International Commission on Illumination (ICI) chromaticity diagram change from (0.18, 0.22) to (0.20, 0.24); from 120℃ to 300℃, the color gradually changes from sky blue to dark blue, and the coordinates on the ILI chromaticity diagram change from (0.20, 0.24) to (0.22, 0.21). When the blue fluorescent material is M-TPSPyPO, from 20℃ to 120℃, the color changes from cyan to sky blue, and the coordinates on the ILI chromaticity diagram change from (0.17, 0.22) to (0.18, 0.23); from 120℃ to 300℃, the color gradually changes from sky blue to dark blue, and the coordinates on the ILI chromaticity diagram change from (0.18, 0.23) to (0.20, 0.19).

[0019] The above-mentioned blue fluorescent material with exciton cycling and thermal exciton properties is used in temperature sensing. The blue fluorescent material exists in the form of a doped thin film containing proton transfer yellow fluorescent material. The doped thin film has proportional emission characteristics, and the color of its proportional emission changes with increasing temperature. The proportional emission is the ratio of the emission intensity of deep blue light to that of yellow light, wherein the emission intensity of deep blue light decreases slowly with increasing temperature, while the emission intensity of yellow light decreases rapidly with increasing temperature.

[0020] Preferably, when the blue fluorescent material is P-TPSPyPO, as the temperature increases from 20℃ to 120℃, the color gradually changes from pinkish-white to light purple, and the coordinates on the International Commission on Illumination (ICI) chromaticity diagram change from (0.38, 0.37) to (0.34, 0.29); as the temperature increases from 120℃ to 200℃, the color gradually changes from light purple to bluish-purple, and the coordinates on the ILI chromaticity diagram change from (0.34, 0.29) to (0.24, 0.15); as the temperature increases from 200℃ to 300℃, the color changes from bluish-purple to dark blue, and the coordinates on the ILI chromaticity diagram change from (0.24, 0.15) to (0.18, 0.07). When the blue fluorescent material is M-TPSPyPO, as the temperature increases from 20℃ to 120℃, the color gradually changes from light pink to light purple, and the coordinates on the ILI chromaticity diagram change from (0.38, 0.36) to (0.33, 0.07). 0.27); As the temperature increases from 120℃ to 200℃, the color gradually changes from light purple to bluish-purple, and the coordinates of the International Commission on Illumination (ICI) chromaticity diagram change from (0.33, 0.27) to (0.22, 0.11); As the temperature increases from 200℃ to 300℃, the color changes from bluish-purple to dark blue, and the coordinates of the ICI chromaticity diagram change from (0.22, 0.11) to (0.18, 0.07).

[0021] Preferably, the proton transfer yellow fluorescent material is SPDDBD-1, with the following structure:

[0022] .

[0023] Furthermore, the preparation method of SPDDBD-1 includes the following steps:

[0024] Step 1: Mix 2-bromo-9,9-dimethyl-9,10-dihydroacridine and sodium hydride, add anhydrous N,N-dimethylformamide under nitrogen atmosphere, stir at room temperature until the solution changes from pale yellow to gray and no bubbles emerge; then add anhydrous N,N-dimethylformamide containing 4,4'-difluorodiphenyl sulfone dropwise, and heat to react; after the reaction is complete, extract and separate the lower organic phase, add anhydrous sodium sulfate to dry, evaporate to dryness, add silica gel powder, use a mixed solvent of petroleum ether and ethyl acetate as eluent, column chromatography, evaporate to dryness to obtain a white solid, then recrystallize and vacuum dry to obtain intermediate 10,10'-(sulfonylbis(4,1-phenylene))bis(2-bromo-9,9-dimethyl-9,10-dihydroacridine);

[0025] Step 2: The intermediates 10,10'-(sulfonylbis(4,1-phenylene))bis(2-bromo-9,9-dimethyl-9,10-dihydroacridine), 2-(benzothiazol-2-yl)-4-(4,4,5,5-tetramethyl-1,3,2-dioxolane-2-yl)phenol and tetra(triphenylphosphine)palladium were mixed, and potassium carbonate, potassium fluoride, toluene and tetrahydrofuran were added under nitrogen atmosphere. The mixture was heated to reflux and reacted. After the reaction was completed, the solvent was removed by pressure distillation, and the lower organic phase was extracted and separated. Anhydrous sodium sulfate was added for drying, and after rotary drying, silica gel powder was added. A mixed solvent of petroleum ether, dichloromethane and ethyl acetate was used as the eluent. After column chromatography, the solid was rotary dried to obtain a yellow-green solid. After recrystallization and vacuum drying, SPDDBD-1 was obtained.

[0026] The above-mentioned blue fluorescent material with exciton cycling and thermal exciton properties is used in a single-molecule blue OLED device. The single-molecule blue OLED device is a multilayer structure stacked on top of each other, consisting of 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 transport layer, an electron injection layer, and a cathode layer from bottom to top. The organic light-emitting layer is made of CBP doped with the blue fluorescent material.

[0027] Preferably, the substrate is made of glass; the anode layer is made of indium tin oxide; the hole injection layer is made of MoO3 with a thickness of 1 nm; the hole transport layer is made of TAPC with a thickness of 50 nm; the electron blocking layer is made of TCTA with a thickness of 5 nm; the organic light-emitting layer has a blue phosphor doping concentration of 15 wt% and a thickness of 30 nm; the hole blocking layer is made of TPBi with a thickness of 5 nm; the electron transport layer is made of TmPyPb with a thickness of 40 nm; the electron injection layer is made of LiF with a thickness of 1 nm; and the cathode layer is made of aluminum with a thickness of 100 nm.

[0028] Beneficial effects: 1. The thin film prepared by doping the blue fluorescent material with exciton cycling and "thermal exciton" properties with the proton transfer yellow light material of the present invention has dual emission characteristics with energy transfer suppression, and can be used as a ratio intensity type temperature sensor with good temperature response in the high temperature range.

[0029] 2. The thin film of the blue fluorescent material with exciton cycling and "thermal exciton" properties in 20 wt% PMMA of the present invention exhibits a significant transition from exciton complex emission to single-molecule emission, with a threshold transition temperature of 120°C, and good threshold response in the high-temperature range.

[0030] 3. The blue fluorescent material of the present invention with exciton cycle and "thermal exciton" properties has suitable molecular energy levels, high luminous efficiency, and good film-forming properties, and can be used as a guest doping material for OLEDs.

[0031] 4. In threshold temperature indication applications, the thin-film threshold temperature sensor of the present invention, made of blue fluorescent material with exciton cycling and "thermal exciton" properties, is simple to fabricate and heat-resistant. The fabricated threshold temperature sensor exhibits a threshold response at 120℃, with a significant threshold color change, high temperature measurement repeatability, and a maximum sensitivity of 139.7℃. -1 .

[0032] 5. In temperature sensing applications, the thin-film temperature sensor of this invention, doped with a blue fluorescent material possessing exciton cycling and "thermal exciton" properties and a proton-transfer yellow fluorescent material, is simple to fabricate and heat-resistant. There is no energy transfer between the blue fluorescent material with exciton cycling and "thermal exciton" properties and the proton-transfer yellow fluorescent material. Temperature-dependent fluorescence color changes can be observed with the naked eye over a wide temperature range (20~300℃), exhibiting high-temperature and wide-range temperature detection properties. The fabricated temperature sensor is stable in air, has good reversibility, and is suitable for temperature measurement of large-area surfaces, with a maximum relative sensitivity of 2.08℃. -1 Even at 280℃, the temperature resolution is still below 0.43℃.

[0033] 6. In organic electroluminescent device applications, the blue fluorescent material OLED device with exciton cycling and "thermal exciton" properties of the present invention is simple to fabricate. A single-molecule blue OLED device can be fabricated by using the blue fluorescent material with exciton cycling and "thermal exciton" properties as the guest material of the emitting layer.

[0034] 7. This invention also provides a reference for other related issues in the same field, and can be used as a basis for expansion and extension, and applied to other related technical solutions in the fields of high temperature threshold indication, high temperature sensing and organic electroluminescence, with a very broad application prospect. Attached Figure Description

[0035] Figure 1 The images show the temperature-dependent spectra of blue fluorescent materials P-TPSPyPO and M-TPSPyPO in MOE solution in embodiments of the present invention, where a is the temperature-dependent spectrum of P-TPSPyPO solution and b is the temperature-dependent spectrum of M-TPSPyPO solution.

[0036] Figure 2 The temperature-dependent spectra of the thin films prepared by blue fluorescent materials P-TPSPyPO and M-TPSPyPO on PMMA substrate in the embodiments of the present invention are shown, where a is the temperature-dependent spectrum of the P-TPSPyPO thin film and b is the temperature-dependent spectrum of the M-TPSPyPO thin film.

[0037] Figure 3 The images show a comparison of the photoluminescence spectra and lifetimes of the two materials described in this invention, P-TPSPyPO and M-TPSPyPO, before and after nitrogen purging in toluene solvent. Image a shows the transient lifetime spectrum of the P-TPSPyPO material before and after nitrogen purging in toluene solvent, with the upper right frame showing the photoluminescence spectrum of the P-TPSPyPO material before and after nitrogen purging in toluene solvent. Image b shows the transient lifetime spectrum of the M-TPSPyPO material before and after nitrogen purging in toluene solvent, with the upper right frame showing the photoluminescence spectrum of the M-TPSPyPO material before and after nitrogen purging in toluene solvent.

[0038] Figure 4 The diagrams show the molecular energy levels of the heat resistance mechanism of the blue fluorescent material in this invention, with a being the energy level diagram of the P-TPSPyPO molecular structure and b being the energy level diagram of the M-TPSPyPO molecular structure.

[0039] Figure 5 The image shows a thin film of blue fluorescent material P-TPSPyPO prepared on PMMA substrate in an embodiment of the present invention, where a is the temperature-dependent spectrum of the P-TPSPyPO thin film and b is the temperature dependence of the ratio of single-molecule emission and excitocomplex emission fluorescence intensity in the P-TPSPyPO thin film.

[0040] Figure 6 The image shows a thin film of blue fluorescent material M-TPSPyPO prepared on PMMA substrate in an embodiment of the present invention, where a is the temperature-dependent spectrum of the P-TPSPyPO thin film and b is the temperature dependence of the ratio of single-molecule emission and excitocomplex emission fluorescence intensity in the M-TPSPyPO thin film.

[0041] Figure 7 The temperature-dependent spectrum of the P-TPSPyPO / SPDDBD-1 thin film in this embodiment of the invention is shown.

[0042] Figure 8 This describes the temperature dependence of the blue and yellow fluorescence intensity ratio in the P-TPSPyPO / SPDDBD-1 film in this embodiment of the invention.

[0043] Figure 9 The temperature-dependent spectrum of the M-TPSPyPO / SPDDBD-1 thin film in this embodiment of the invention is shown.

[0044] Figure 10 This describes the temperature dependence of the blue and yellow fluorescence intensity ratio in the M-TPSPyPO / SPDDBD-1 film in this embodiment of the invention.

[0045] Figure 11This is a device structure diagram of a single-molecule blue OLED based on P-TPSPyPO in an embodiment of the present invention. The numbers in the diagram are in eV.

[0046] Figure 12 The following are performance diagrams of the single-molecule blue OLED device based on P-TPSPyPO according to an embodiment of the present invention: a is the current efficiency-brightness-power density diagram, b is the external quantum efficiency-brightness diagram, c is the current density-voltage-brightness diagram, and d is the normalized electroluminescence intensity diagram.

[0047] Figure 13 This is a device structure diagram of a single-molecule blue OLED based on M-TPSPyPO in an embodiment of the present invention. The numbers in the diagram are in eV.

[0048] Figure 14 The following are performance diagrams of the single-molecule blue OLED device based on M-TPSPyPO according to the embodiments of the present invention: a is the current efficiency-brightness-power efficiency diagram, b is the external quantum efficiency-brightness diagram, c is the current density-voltage-brightness diagram, and d is the normalized electroluminescence intensity diagram.

[0049] Figure 15 The diagrams show the molecular energy levels of the blue fluorescent material in the single-molecule blue OLED device in this embodiment of the invention. a is the molecular energy level diagram of P-TPSPyPO, and b is the molecular energy level diagram of M-TPSPyPO. Detailed Implementation

[0050] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0051] Example 1

[0052] A method for preparing a blue fluorescent material P-TPSPyPO with exciton cycling and "thermal exciton" properties, specifically including the following steps:

[0053] Synthesis of intermediate (4-(6-bromopyrene-1-yl)phenyl)triphenylsilane:

[0054] Step 1: Take triphenyl(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborhexacyclopentan-2-yl)phenyl)silane (4g, 8.64mmol), 1,6-dibromopyrene (3.11g, 8.64mmol), tetra(triphenylphosphine)palladium (499.7mg, 432.45µmol), potassium fluoride (1.5g, 25.94mmol) and potassium carbonate (3.58g, 25.94mmol) and add them to a 100 mL three-necked round-bottom flask. Use a double-row tube to evacuate the vacuum, purge with nitrogen three times, and insert a nitrogen balloon.

[0055] Step 2: Under nitrogen atmosphere, add 60 mL toluene, 60 mL tetrahydrofuran and 10 mL water using a syringe; place the reaction apparatus in an oil bath, with the liquid level in the flask slightly higher than the liquid level in the oil bath, and heat under reflux for 24 hours.

[0056] Step 3: After the reaction was complete, the sample was extracted with water and dichloromethane to separate the lower organic phase. Anhydrous sodium sulfate was added and the mixture was dried. After rotary evaporation, silica gel powder was added and the sample was stirred. A mixed solvent of petroleum ether / dichloromethane (5:1, v / v) was used as the eluent. After column chromatography, the sample was dried by rotary evaporation to obtain a white solid. The solid was then recrystallized from a solution of dichloromethane and n-hexane. After vacuum drying at 60°C for 24 hours, 3.2 g of the intermediate (4-(6-bromopyrene-1-yl)phenyl)triphenylsilane was obtained, with a yield of 60%. The product was identified by 1H NMR spectroscopy. 1 ¹H NMR (400 MHz, Chloroform-d) δ 8.47 (d, J = 9.2 Hz, 1H), 8.31–8.25 (m, 2H), 8.24 (s, 1H), 8.20 (d, J = 9.2 Hz, 1H), 8.05 (d, J = 7.8 Hz, 1H), 8.00 (t, J = 8.0 Hz, 2H), 7.78 (d, J = 7.7 Hz, 2H), 7.72–7.66 (d, J = 6.4 Hz, 6H), 7.65 (d, J = 7.7 Hz, 2H), 7.46 (m, 9H). The reaction equation is:

[0057] .

[0058] Synthesis of p-TPSPyPO:

[0059] Step 1: Take the intermediate (4-(6-bromopyrene-1-yl)phenyl)triphenylsilane (3.0 g, 4.87 mmol), diphenylphosphine oxide (1.18 g, 5.85 mmol), palladium acetate (54.70 mg, 243.65 µmol), 1,1'-bis(diphenylphosphine)ferrocene (270.15 mg, 487.29 µmol) and cesium carbonate (3.18 g, 9.75 mmol) and add them to a 100 mL three-necked round-bottom flask. Use a double-row tube to evacuate the vacuum, purge with nitrogen three times, and insert a nitrogen balloon.

[0060] Step 2: Under nitrogen atmosphere, add 80 mL of anhydrous N,N-dimethylformamide using a syringe; place the reaction apparatus in an oil bath, with the liquid level in the flask slightly higher than the liquid level in the oil bath, and heat under reflux for 24 hours.

[0061] Step 3: After the reaction was complete, the solvent was removed by vacuum distillation, followed by extraction with water and dichloromethane to separate the lower organic phase. Anhydrous sodium sulfate was added for drying. After rotary evaporation, silica gel powder was added and mixed. A mixture of petroleum ether / ethyl acetate (1:3, v / v) was used as the eluent. Column chromatography was performed, followed by rotary evaporation to obtain a white solid. This solid was then recrystallized from a solution of dichloromethane and n-hexane. After vacuum drying at 60°C for 24 hours, 1.62 g of the blue light material was obtained, with a yield of 45.11%. The product was identified by 1H NMR spectroscopy and high-resolution mass spectrometry. 1 H NMR (400 MHz, Chloroform-d) δ 8.95 (d, J = 9.2, 1.0 Hz,1H), 8.34 (d, J = 9.3 Hz, 1H), 8.27 (d, J = 8.0 Hz, 1H), 8.14 -7.98 (m, 4H),7.82-7.71 (m, 6H), 7.68 (m, 7H), 7.66-7.61 (d, J = 8.12 Hz, 2H), 7.61-7.54(m, 2H), 7.46 (m, 13H). HRMS (EI) m / z: 737.24065 [M+H]+. Anal. Calcd forC 52 H 37 OPSi (736.2351). The reaction formula is:

[0062] .

[0063] A method for preparing a blue fluorescent material M-TPSPyPO with exciton cycling and "thermal exciton" properties, specifically including the following steps:

[0064] Synthesis of intermediate (3-(6-bromopyrene-1-yl)phenyl)triphenylsilane:

[0065] Step 1: Take triphenyl(3-(4,4,5,5-tetramethyl-1,3,2-dioxoboronyl-2-yl)phenyl)silane (4g, 8.65mmol), 1,6-dibromopyrene (3.43g, 9.51mmol), tetra(triphenylphosphine)palladium (499.7mg, 432.45µmol), potassium fluoride (1.5g, 25.95mmol) and potassium carbonate (3.59g, 25.95mmol) and add them to a 100 mL three-necked round-bottom flask. Use a double-row tube to evacuate the vacuum, purge with nitrogen three times, and insert a nitrogen balloon.

[0066] Step 2: Under nitrogen atmosphere, add 60 mL toluene, 60 mL tetrahydrofuran and 10 mL water using a syringe; place the reaction apparatus in an oil bath, with the liquid level in the flask slightly higher than the liquid level in the oil bath, and heat under reflux for 24 hours.

[0067] Step 3: After the reaction was complete, the sample was extracted with water and dichloromethane to separate the lower organic phase. Anhydrous sodium sulfate was added and the mixture was dried. After rotary evaporation, silica gel powder was added and the sample was stirred. A mixed solvent of petroleum ether / dichloromethane (5:1, v / v) was used as the eluent. After column chromatography, the sample was dried by rotary evaporation to obtain a white solid. The solid was then recrystallized from a solution of dichloromethane and n-hexane. After vacuum drying at 60°C for 24 hours, 2.2 g of the intermediate (3-(6-bromopyrene-1-yl)phenyl)triphenylsilane was obtained, with a yield of 41%. The product was identified by 1H NMR spectroscopy. 1 ¹H NMR (400 MHz, Chloroform-d) δ 8.45 (d, J = 9.2 Hz, 1H), 8.24 (d, J = 8.6 Hz, 2H), 8.17 (d, J = 9.3 Hz, 2H), 7.99 (d, J = 8.0 Hz, 2H), 7.92 (d, J = 9.3 Hz, 1H), 7.86 (s, 1H), 7.68 (m, 2H), 7.65 (d, J = 7.0 Hz, 6H), 7.58 (t, J = 7.5 Hz, 1H), 7.47–7.35 (m, 9H). The reaction equation is:

[0068] .

[0069] Synthesis of M-TPSPyPO:

[0070] Step 1: Take intermediate (3-(6-bromopyrene-1-yl)phenyl)triphenylsilane (2.0 g, 3.25 mmol), diphenylphosphine oxide (788.22 mg, 3.90 mmol), palladium acetate (36.47 mg, 162.43 µmol), 1,1'-bis(diphenylphosphine)ferrocene (180.10 mg, 324.86 µmol) and cesium carbonate (1.59 g, 4.87 mmol) and add them to a 100 mL three-necked round-bottom flask. Use a double-row tube to evacuate the vacuum, purge with nitrogen three times, and insert a nitrogen balloon.

[0071] Step 2: Under nitrogen atmosphere, add 60 mL of anhydrous N,N-dimethylformamide using a syringe; place the reaction apparatus in an oil bath, with the liquid level in the flask slightly higher than the liquid level in the oil bath, and heat under reflux for 24 hours.

[0072] Step 3: After the reaction is complete, the solvent is removed by vacuum distillation, followed by extraction with water and dichloromethane to separate the lower organic phase. Anhydrous sodium sulfate is added for drying. After rotary evaporation, silica gel powder is added and mixed. A mixture of petroleum ether / ethyl acetate (1:3, v / v) is used as the eluent. After column chromatography, rotary evaporation yields a white solid. The solid is then recrystallized from dichloromethane and n-hexane solution and dried under vacuum at 60°C for 24 hours to obtain 490 mg of the blue fluorescent material, with a yield of 20.74%. The product was identified by 1H NMR and high-resolution mass spectrometry: 1H NMR (400 MHz, Chloroform-d) δ 8.92 (d, J = 9.3, 1.0 Hz, 1H), 8.29–8.20 (m, 2H), 8.07 (d, J = 9.3 Hz, 1H), 8.05–7.98 (m, 2H), 7.96 (d, J = 9.3 Hz, HRMS (EI) m / z: 737.24078 [M+H]+.Anal. Calcdfor C 52 H 37 OPSi (736.2351). The reaction formula is:

[0073] .

[0074] The preparation method of the proton-transfer yellow fluorescent material SPDDBD-1 specifically includes the following steps:

[0075] Synthesis of intermediate 10,10'-(sulfonylbis(4,1-phenylene))bis(2-bromo-9,9-dimethyl-9,10-dihydroacridine):

[0076] Step 1: Mix 2-bromo-9,9-dimethyl-9,10-dihydroacrylidine (400 mg, 1.39 mmol) and sodium hydride (99 mg, 4.16 mmol) in a 100 mL three-necked round-bottom flask, evacuate using a double-row tube, purge with nitrogen three times, and insert a nitrogen balloon.

[0077] Step 2: Add 30 mL of anhydrous N,N-dimethylformamide using a syringe, and stir at room temperature for 20 minutes until the solution changes from pale yellow to gray and no more bubbles appear. Then dissolve 176 mg (693 mmol) of 4,4'-difluorodiphenyl sulfone in 10 mL of anhydrous N,N-dimethylformamide, and then slowly add it dropwise to a mixed solution of 2-bromo-9,9-dimethyl-9,10-dihydroacrylidine and sodium hydride using a syringe. After the addition is complete, react at 100°C for 24 hours.

[0078] Step 3: After the reaction was complete, the sample was extracted with water and dichloromethane to separate the lower organic phase. Anhydrous sodium sulfate was added and the mixture was dried. After rotary evaporation, silica gel powder was added and the sample was eluent with a mixture of petroleum ether / ethyl acetate (1:1, v / v). After column chromatography, the solid was dried by rotary evaporation to obtain a white solid. The solid was then recrystallized from dichloromethane and n-hexane solution and dried under vacuum at 60°C for 24 hours to obtain 340 mg of intermediate 10,10'-(sulfonylbis(4,1-phenylene))bis(2-bromo-9,9-dimethyl-9,10-dihydroacridine), with a yield of 31%. The product was identified by 1H NMR spectroscopy. 1 ¹H NMR (400 MHz, d⁶-DMSO, ppm): δ 8.34–8.32 (d, J = 8.80 Hz, 4H), 7.71–7.70 (d, J = 5.60 Hz, 4H), 7.62–7.61 (d, J = 2.5 Hz, 2H), 7.52–7.50 (d, J = 8.50 Hz, 2H), 7.18–7.16 (d, J = 8.3 Hz, 2H), 7.03–6.95 (m, 4H), 6.19–6.14 (m, 4H), 1.60 (s, 12H). The reaction equation is:

[0079] .

[0080] Synthesis of SPDDBD-1:

[0081] Step 1: Take intermediate 10,10'-(sulfonylbis(4,1-phenylene))bis(2-bromo-9,9-dimethyl-9,10-dihydroacridine) (340 mg, 450 mmol), 2-(benzothiazolyl-2-yl)-4-(4,4,5,5-tetramethyl-1,3,2-dioxolane-2-yl)phenol (300 mg, 860 mmol) and tetra(triphenylphosphine)palladium (25 mg, 21 μmol) and add them to a 100 mL three-necked round-bottom flask. Vacuum the flask three times using a double-row tube and insert a nitrogen balloon.

[0082] Step 2: Under nitrogen atmosphere, add 1 mL of a pre-prepared 2 mol / L potassium carbonate and 2 mol / L potassium fluoride mixed aqueous solution using a syringe, and then add 30 mL of a mixed solvent of toluene and tetrahydrofuran in a 1:1 ratio; place the reaction apparatus in an oil bath and heat under reflux for 24 hours.

[0083] Step 3: After the reaction is complete, the solvent is removed by vacuum distillation, followed by extraction with water and dichloromethane to separate the lower organic phase. Anhydrous sodium sulfate is added for drying. After rotary evaporation, silica gel powder is added and mixed. A mixed solvent of petroleum ether / dichloromethane / ethyl acetate (5:1:1, v / v) is used as the eluent. After column chromatography, rotary evaporation yields a yellow-green solid. This solid is then recrystallized from a solution of dichloromethane and n-hexane. After vacuum drying at 60°C for 24 hours, 85 mg of the yellow fluorescent material is obtained, with a yield of 20%. The product is identified by 1H NMR and high-resolution mass spectrometry. 1 H NMR (400 MHz, CDCl3, ppm): δ8.35-8.32 (d, J=8.30 Hz, 4H), 8.02-8.00 (d, J=7.80 Hz, 2H), 7.89-7.87 (d, J=8.10 Hz, 2H), 7.82-7.81 (s, 2H), 7.70-7.69 (s, 2H), 7.67-7.65 (d, J=8.30 Hz, 4H), 7.61-7.51(m, 6H), 7.44-7.41 (t, J=6.95 Hz, 2H), 7.30-7.29 (d, J=7.30Hz, 1H), 7.16-7.14(d, J=8.43 Hz, 2H), 7.10-7.05 (m, 4H), 6.46-6.44 (d, J=8.17 Hz, 2H), 6.40-6.38 (d, J=6.26 Hz, 2H), 1.78 (s, 12H). HRMS: m / z calcd for [M+H] +C 68 H 50 N4O4S3: 1082.2994; found: 1083.3071. The reaction formula is:

[0084] .

[0085] Example 2

[0086] A blue fluorescent material with exciton cycling and "thermal exciton" properties, the blue fluorescent material with exciton cycling and "thermal exciton" properties is named diphenyl(6-(4-(triphenylsilyl)phenyl)pyrene-1-yl)phosphine oxide (P-TPSPyPO) or diphenyl(6-(3-(triphenylsilyl)phenyl)pyrene-1-yl)phosphine oxide (M-TPSPyPO).

[0087] In this embodiment, solutions of P-TPSPyPO and M-TPSPyPO were first prepared by dissolving P-TPSPyPO or M-TPSPyPO in 2-methoxyethyl ether (MOE) solvent. The concentration of the solvent MOE was 1×10⁻⁶. -5 mol / L, the specific steps are as follows:

[0088] Step 1: Weigh 1×10 -5 mol of P-TPSPyPO or M-TPSPyPO;

[0089] Step 2: Take out 10 mL of MOE solution;

[0090] Step 3: Weigh out the 1×10 -5 mol of P-TPSPyPO or M-TPSPyPO is dissolved in 10 mL of MOE solution;

[0091] Step 4: Dilute the solution 100 times;

[0092] Their temperature-dependent spectra were tested in the temperature range of 20℃ to 100℃. For example... Figure 1 The fluorescence intensity of P-TPSPyPO and M-TPSPyPO solutions decreased only slightly with increasing temperature, indicating that P-TPSPyPO or M-TPSPyPO has high temperature resistance in solution.

[0093] Using PMMA as a substrate, P-TPSPyPO, M-TPSPyPO, and PMMA were dissolved together and then drop-coated onto a quartz plate using a dropper to prepare P-TPSPyPO and M-TPSPyPO films. PMMA accounted for 99% of the total mass, while P-TPSPyPO and M-TPSPyPO accounted for 1% of the total mass. The specific steps are as follows:

[0094] Step 1: Weigh out a trace amount of P-TPSPyPO or M-TPSPyPO;

[0095] Step 2: Weigh out a small amount of PMMA, the mass of which is 99 times that of P-TPSPyPO or M-TPSPyPO;

[0096] Step 3: Dissolve the weighed P-TPSPyPO or M-TPSPyPO and the weighed PMMA;

[0097] Step 4: Apply the dissolved solution onto a quartz plate using a dropper to prepare a thin film.

[0098] Their temperature-dependent spectra were measured in the temperature range of 20℃ to 300℃. For example... Figure 2 The P-TPSPyPO or M-TPSPyPO films maintained strong fluorescence intensity at 300℃, proving that the P-TPSPyPO or M-TPSPyPO films have high temperature resistance.

[0099] The heat resistance mechanism was explained by calculating the molecular energy level diagrams of P-TPSPyPO and M-TPSPyPO. The energy gaps between T2 and S1 were both relatively small, at 0.06 eV, and the spin-orbit coupling matrix coefficient between T2 and S1 was 0.14 cm⁻¹. -1 and 0.09cm -1 Reverse intersystem crossing (RISC) primarily occurs between S1 and T2 states. Simultaneously, the large energy difference between T2 and T1 (1.29 eV and 1.30 eV respectively) suppresses internal conversion efficiency and promotes the RISC rate. At increasing temperatures, excitons in the S1 state enter the T2 state via ISC and subsequently return to the S1 state via RISC. This thermally promoted RISC process and exciton cycling effectively suppress non-radiative decay, allowing P-TPSPyPO or M-TPSPyPO to maintain stable luminescence intensity even at high temperatures. Experimental results are as follows... Figure 1-4 As shown.

[0100] Example 3

[0101] In this embodiment, diphenyl(6-(4-(triphenylsilyl)phenyl)pyrene-1-yl)phosphine oxide (P-TPSPyPO) or diphenyl(6-(3-(triphenylsilyl)phenyl)pyrene-1-yl)phosphine oxide (M-TPSPyPO) is used, and the transparent polymer matrix used is PMMA.

[0102] P-TPSPyPO or M-TPSPyPO and PMMA were mutually dissolved and then drop-coated onto a quartz plate using a dropper to prepare a P-TPSPyPO film. The P-TPSPyPO or M-TPSPyPO accounted for 20% of the total mass, and PMMA accounted for 80%. The specific steps are as follows:

[0103] Step 1: Weigh out a trace amount of P-TPSPyPO or M-TPSPyPO;

[0104] Step 2: Weigh out a small amount of PMMA, which is 4 times the mass of P-TPSPyPO or M-TPSPyPO.

[0105] Step 2: Dissolve the weighed P-TPSPyPO or M-TPSPyPO with PMMA;

[0106] Step 3: Apply the dissolved solution onto a quartz plate using a dropper to prepare a thin film.

[0107] P-TPSPyPO or M-TPSPyPO accounted for 20% of the total mass, and PMMA accounted for 80%. Its temperature dependence was measured in the range of 20℃ to 300℃. With increasing temperature, the emission peak intensity of the excitocomplex decreased, while the single-molecule emission peak gradually appeared and completely dominated. This ratiometric fluorescence change was quantified, and the single-molecule emission (Ig) was... M ) and excitokinase complex emission (I E The relationship between the fluorescence intensity ratio and temperature (T) can be well plotted using correlation curves. The threshold temperature is 120℃, and the threshold color changes from cyan to sky blue. The threshold of P-TPSPyPO varies from 120℃ to 160℃, with a sensitivity of 139.7%℃. -1 The threshold of M-TPSPyPO varies from 120℃ to 220℃, with a sensitivity of 47.9%℃. -1 The experimental results are as follows: Figure 5-6 As shown.

[0108] Example 4

[0109] In this embodiment, diphenyl(6-(4-(triphenylsilyl)phenyl)pyrene-1-yl)phosphine oxide (P-TPSPyPO) was used. The proton transfer yellow fluorescent material based on the large Stokes shift of 2-(2'-hydroxyphenyl)benzoazole was 4,4'-((sulfonylbis(4,1-phenylene))bis(9,9-dimethyl-9,10-dihydroacridine-10,2-diyl))bis(2-(benzo[d]thiazolyl)phenol) (SPDDBD-1), and the transparent polymer matrix used was PMMA.

[0110] P-TPSPyPO and SPDDBD-1 were dissolved together with PMMA in a mass ratio of 1:3, and then drop-coated onto a quartz plate using a dropper to prepare a P-TPSPyPO and SPDDBD-1 thin film. PMMA accounted for 99% of the total mass, and P-TPSPyPO and SPDDBD-1 accounted for 1% of the total mass. The specific steps are as follows:

[0111] Step 1: Weigh out a trace amount of P-TPSPyPO;

[0112] Step 2: Weigh out a trace amount of SPDDBD-1, the mass of which is 3 times the mass of the weighed P-TPSPyPO;

[0113] Step 2: Weigh out a small amount of PMMA, the mass of which is 99 times the sum of the masses of P-TPSPyPO and SPDDBD-1;

[0114] Step 3: Dissolve the weighed P-TPSPyPO, SPDDBD-1, and weighed PMMA;

[0115] Step 4: Apply the dissolved solution onto a quartz plate using a dropper to prepare a thin film.

[0116] P-TPSPyPO and SPDDBD-1 accounted for 1% of the total mass, while PMMA accounted for 99%. The temperature dependence was measured within the range of 20℃ to 300℃. With increasing temperature, the intensity of the deep blue emission peak decreased relatively slowly, while the intensity of the yellow peak decreased more significantly. This ratiometric fluorescence change was quantified, and the deep blue emission (Ig) was... 407 ) and yellow light emission (I 570 The relationship between the fluorescence intensity ratio and temperature (T) can be well fitted by the following function:

[0117] I 407 / I 570 = 3.6293 - 0.1642T + 0.0039T 2 -3.7497×10 -5 T 3 +1.5722×10 -7 T 4 -2.1534×10 -10 T 5 Correlation coefficient R 2 It is 0.9998.

[0118] The film exhibits a significant color change with temperature: from 20℃ to 120℃, the color gradually changes from pinkish-white to light purple; from 120℃ to 200℃, the color gradually changes from light purple to bluish-purple; and from 200℃ to 300℃, the color changes from bluish-purple to dark blue. The maximum relative sensitivity of the film is 2.08%℃. -1 Maximum absolute sensitivity 40.9×10 -2 ℃ -1 The error is less than 1%, and the temperature resolution at 280℃ is still less than 0.43℃. Experimental results are as follows... Figure 7-8 As shown.

[0119] Example 5

[0120] In this embodiment, diphenyl(6-(3-(triphenylsilyl)phenyl)pyrene-1-yl)phosphine oxide (M-TPSPyPO) was used. The proton transfer yellow fluorescent material based on the large Stokes shift of 2-(2'-hydroxyphenyl)benzoazole was 4,4'-((sulfonylbis(4,1-phenylene))bis(9,9-dimethyl-9,10-dihydroacridine-10,2-diyl))bis(2-(benzo[d]thiazolyl)phenol) (SPDDBD-1), and the transparent polymer matrix used was PMMA.

[0121] M-TPSPyPO and SPDDBD-1 were dissolved together with PMMA in a mass ratio of 1:3, and then drop-coated onto a quartz plate using a dropper to prepare an M-TPSPyPO and SPDDBD-1 thin film. PMMA accounted for 99% of the total mass, while M-TPSPyPO and SPDDBD-1 accounted for 1% of the total mass. The specific steps are as follows:

[0122] Step 1: Weigh out a trace amount of M-TPSPyPO;

[0123] Step 2: Weigh out a trace amount of SPDDBD-1, the mass of which is 3 times the mass of the weighed M-TPSPyPO;

[0124] Step 2: Weigh out a small amount of PMMA, the mass of which is 99 times the sum of the masses of M-TPSPyPO and SPDDBD-1.

[0125] Step 3: Dissolve the weighed M-TPSPyPO, SPDDBD-1, and weighed PMMA;

[0126] Step 4: Apply the dissolved solution onto a quartz plate using a dropper to prepare a thin film.

[0127] M-TPSPyPO and SPDDBD-1 accounted for 1% of the total mass, while PMMA accounted for 99%. The temperature dependence was measured within the range of 20℃ to 300℃. With increasing temperature, the intensity of the deep blue emission peak decreased relatively slowly, while the intensity of the yellow peak decreased more significantly. This ratio of fluorescence change was quantified, and the deep blue light (I... 404 ) and yellow light emission (I 570 The relationship between the fluorescence intensity ratio and temperature (T) can be well fitted by the following function:

[0128] I 404 / I 570 = 5.3052 - 0.2268T + 0.0056T 2 -5.5837×10 -5 T 3 +2.4200×10-7 T 4 -3.4831×10 -10 T 5 Correlation coefficient R 2 It is 0.9998.

[0129] The film exhibits a significant color change with temperature: from 20℃ to 120℃, the color gradually changes from light pink to light purple; from 120℃ to 200℃, the color gradually changes from light purple to bluish-purple; and from 200℃ to 300℃, the color changes from bluish-purple to dark blue. The maximum relative sensitivity of the film is 1.93%℃. -1 Maximum absolute sensitivity 45.7×10 -2 ℃ -1 The error is less than 1%, and the temperature resolution at 280℃ is still less than 0.43℃. Experimental results are as follows... Figure 9-10 As shown.

[0130] Example 6

[0131] A single-molecule blue OLED device, the single-molecule blue OLED device comprising an organic light-emitting layer, wherein the material of the organic light-emitting layer is diphenyl(6-(4-(triphenylsilyl)phenyl)pyrene-1-yl)phosphine oxide (P-TPSPyPO) or diphenyl(6-(3-(triphenylsilyl)phenyl)pyrene-1-yl)phosphine oxide (M-TPSPyPO) doped with the host material CBP.

[0132] The single-molecule blue OLED device has a multilayer structure stacked vertically, consisting of, 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 transport layer, an electron injection layer, and a cathode layer. The substrate is made of glass; the anode layer is made of an inorganic material, specifically indium tin oxide (ITO); the hole injection layer is made of MoO3 with a thickness of 1 nm; the hole transport layer is made of TAPC with a thickness of 50 nm; and the electron blocking layer is made of TCTA. The electron blocking layer has a thickness of 5 nm; the organic light-emitting layer is made of CBP doped with P-TPSPyPO or M-TPSPyPO, with a doping concentration of 15 wt% and a thickness of 30 nm; the hole blocking layer is made of TPBi and has a thickness of 5 nm; the electron transport layer is made of TmPyPb and has a thickness of 40 nm; the electron injection layer is made of LiF and has a thickness of 1 nm; and the cathode layer is made of aluminum and has a thickness of 100 nm.

[0133] The specific manufacturing process of this embodiment is as follows:

[0134] Step 1: Clean the ITO (Indium Tin Oxide) glass. Clean the ITO glass ultrasonically with acetone, water and ethanol for 15 minutes each, and then put it in an oven to dry for 2 hours.

[0135] Step 2: Plasma treatment of the oven-dried ITO (indium tin oxide) glass for 50 seconds;

[0136] Step 3: Vacuum evaporation of a hole-injection layer MoO3 on the anode layer of the ITO substrate at a rate of 1 Hz / s and a film thickness of 1 nm.

[0137] Step 3: Vacuum evaporation of hole transport layer TAPC on hole injection layer at a rate of 2Hz / s and a film thickness of 50nm;

[0138] Step 4: Vacuum evaporation of an electron blocking layer TCTA on the hole transport layer at a rate of 2 Hz / s and a film thickness of 5-10 nm;

[0139] Step 5: Evaporate an organic light-emitting layer CBP (P-TPSPyPO or M-TPSPyPO) onto the electron blocking layer at a rate of 2 Hz / s and a film thickness of 30 nm.

[0140] Step 6: Vacuum evaporation of TPBI as a hole blocking layer on top of the organic light-emitting layer at a rate of 2 Hz / s and a film thickness of 5-10 nm.

[0141] Step 7: On top of the hole blocking layer, TmPyPb as an electron transport layer is vacuum-deposited at a rate of 2Hz / s and a thickness of 40nm.

[0142] Step 8: On the electron transport layer, LiF is vacuum-deposited as the electron injection layer at a deposition rate of 0.1 Hz / s and a thickness of 1 nm.

[0143] Step 9: Vacuum evaporation of a cathode layer Al with a thickness of 100 nm is performed on top of the electron injection layer.

[0144] The single-molecule blue OLED device in this embodiment has a device structure of ITO / TAPC / TCTA / CBP: (P-TPSPyPO or M-TPSPyPO) / TPBI / TmPyPb / LiF / Al. During vacuum evaporation, the pressure is <1.0×10⁻⁶. -3 Pa, wherein the compound diphenyl(6-(4-(triphenylsilyl)phenyl)pyrene-1-yl)phosphine oxide (P-TPSPyPO) or diphenyl(6-(3-(triphenylsilyl)phenyl)pyrene-1-yl)phosphine oxide (M-TPSPyPO) is used as the light-emitting material of the device.

[0145] The device was tested for OLED properties. The turn-on voltage was 3.7V or 3.4V, and the maximum brightness was 3473 cd / m². 2 Or 3104 cd / m 2 The maximum current efficiency is 2.62 cd / A or 2.67 cd / A, the maximum power efficiency is 1.80 lm / W or 2.25 lm / W, the maximum external quantum efficiency is 2.72% or 2.25%, and the CIE chromaticity diagram coordinates are (0.149, 0.100) or (0.158, 0.157). Calculating the molecular energy level diagrams of P-TPSPyPO and M-TPSPyPO, the band gap between T2 and S1 is relatively small, both at 0.06 eV. The spin-orbit coupling matrix coefficient between T2 and S1 is 0.14 cm⁻¹. -1 and 0.09cm -1 The reverse intersystem crossing mainly occurs between S1 and T2. Meanwhile, the large energy difference between T2 and T1 (1.29 eV and 1.30 eV respectively) suppresses the internal conversion efficiency and promotes the reverse intersystem crossing rate. This indicates that the excitons within the blue light-emitting material molecules undergo a "thermal exciton" process, where excitons transition from a high-energy triplet state to a singlet state via reverse intersystem crossing. Experimental results are as follows... Figure 11-15 As shown.

[0146] This invention proposes a blue fluorescent material with exciton cycling and "thermal exciton" properties, which is used to prepare a high-temperature threshold temperature indicating film and a high-temperature temperature sensing film by doping it with a proton transfer yellow material. Both films exhibit excellent heat resistance, stability, repeatability, and high sensitivity. The single-molecule blue OLED devices described in this invention possess "thermal exciton" properties, have good efficiency, and are simple to fabricate. The threshold temperature indicator, temperature sensor, and single-molecule blue OLED devices described in this invention have high application and promotion value.

[0147] This invention also provides a reference for other related issues in the same field, and can be used as a basis for expansion and extension, and applied to other related technical solutions in the fields of temperature sensing and organic electroluminescence, with a very broad application prospect.

Claims

1. A blue fluorescent material having an exciton cycle and a hot exciton property, characterized by, The blue fluorescent material is P-TPSPyPO or M-TPSPyPO, and their structural formulas are as follows: 、 。 2.The blue fluorescent material with exciton cycle and hot exciton properties according to claim 1, wherein, The blue fluorescent material exhibits fluorescence and heat resistance under both solution and thin film conditions. ​ 3. The method for preparing a blue fluorescent material with exciton cycling and thermal exciton properties as described in claim 1, characterized in that, The steps include the following: Step 1: Mix the intermediate (4-(6-bromopyrene-1-yl)phenyl)triphenylsilane or (3-(6-bromopyrene-1-yl)phenyl)triphenylsilane with diphenylphosphine oxide, palladium acetate, 1,1'-bis(diphenylphosphine)ferrocene and cesium carbonate to obtain a mixture; Step 2: Inject anhydrous N,N-dimethylformamide solvent into the mixture under nitrogen atmosphere and heat to reflux for reaction; Step 3: After the reaction, the solvent is removed by vacuum distillation, and the lower organic phase is obtained by extraction and separation. Anhydrous sodium sulfate is added for drying, and after rotary drying, silica gel powder is added. A mixed solvent of petroleum ether and ethyl acetate is used as the eluent. After column chromatography, the white solid is obtained by rotary drying. Then, after recrystallization and vacuum drying, the blue fluorescent material is obtained.

4. The method for preparing a blue fluorescent material with exciton cycling and thermal exciton properties according to claim 3, characterized in that, The intermediate is prepared as follows: Triphenyl(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborhexacyclopentan-2-yl)phenyl)silane or triphenyl(3-(4,4,5,5-tetramethyl-1,3,2-dioxaborhexacyclopentan-2-yl)phenyl)silane is mixed with 1,6-dibromopyrene, tetra(triphenylphosphine)palladium, potassium fluoride and potassium carbonate. Toluene, tetrahydrofuran and water are added under nitrogen atmosphere, and the mixture is heated under reflux. After the reaction is completed, the lower organic phase is extracted and separated. Anhydrous sodium sulfate is added for drying, and after rotary drying, silica gel powder is added. A mixed solvent of petroleum ether and dichloromethane is used as the eluent. After column chromatography, the solid is rotary dried to obtain a white solid. The solid is then recrystallized and dried under vacuum to obtain the intermediate.

5. The application of the blue fluorescent material with exciton cycling and thermal exciton properties as described in claim 1 in threshold temperature indication, characterized in that, The blue fluorescent material exists in the form of a thin film in the threshold temperature indication and exhibits a threshold temperature response at 120°C.

6. The application of the blue fluorescent material with exciton cycling and thermal exciton properties according to claim 5 in threshold temperature indication, characterized in that, When the blue fluorescent material is P-TPSPyPO, from 20℃ to 120℃, the color abruptly changes from cyan to sky blue, and the coordinates on the International Commission on Illumination (ICI) chromaticity diagram change from (0.18, 0.22) to (0.20, 0.24); from 120℃ to 300℃, the color gradually changes from sky blue to dark blue, and the coordinates on the ILI chromaticity diagram change from (0.20, 0.24) to (0.22, 0.21). When the blue fluorescent material is M-TPSPyPO, from 20℃ to 120℃, the color changes from cyan to sky blue, and the coordinates on the ILI chromaticity diagram change from (0.17, 0.22) to (0.18, 0.23); from 120℃ to 300℃, the color gradually changes from sky blue to dark blue, and the coordinates on the ILI chromaticity diagram change from (0.18, 0.23) to (0.20, 0.19).

7. The application of the blue fluorescent material with exciton cycling and thermal exciton properties as described in claim 1 in temperature sensing, characterized in that, The blue fluorescent material exists in the temperature sensing as a doped thin film containing proton transfer yellow fluorescent material. The doped thin film has proportional emission characteristics, and the color of its proportional emission changes with increasing temperature. The emission ratio is the ratio of the emission intensity of deep blue light to that of yellow light, wherein the emission intensity of deep blue light decreases slowly with increasing temperature, while the emission intensity of yellow light decreases rapidly with increasing temperature.

8. The application of the blue fluorescent material with exciton cycling and thermal exciton properties according to claim 7 in temperature sensing, characterized in that, When the blue fluorescent material is P-TPSPyPO, as the temperature increases from 20℃ to 120℃, the color gradually changes from pinkish-white to light purple, and the coordinates on the International Commission on Illumination (ICI) chromaticity diagram change from (0.38, 0.37) to (0.34, 0.29); as the temperature increases from 120℃ to 200℃, the color gradually changes from light purple to bluish-purple, and the coordinates on the ILI chromaticity diagram change from (0.34, 0.29) to (0.24, 0.15); as the temperature increases from 200℃ to 300℃, the color changes from bluish-purple to dark blue, and the coordinates on the ILI chromaticity diagram change from (0.24, 0.15) to (0.18, 0.07). When the blue fluorescent material is M-TPSPyPO, as the temperature increases from 20℃ to 120℃, the color gradually changes from light pink to light purple, and the coordinates on the ILI chromaticity diagram change from (0.38, 0.36) to (0.33, 0.07). 0.27); As the temperature increases from 120℃ to 200℃, the color gradually changes from light purple to bluish-purple, and the coordinates of the International Commission on Illumination (ICI) chromaticity diagram change from (0.33, 0.27) to (0.22, 0.11); As the temperature increases from 200℃ to 300℃, the color changes from bluish-purple to dark blue, and the coordinates of the ICI chromaticity diagram change from (0.22, 0.11) to (0.18, 0.07).

9. The application of the blue fluorescent material with exciton cycling and thermal exciton properties according to claim 7 in temperature sensing, characterized in that, The proton-transfer yellow fluorescent material is SPDDBD-1, and its structure is as follows: ； Its preparation method includes the following steps: Step 1: Mix 2-bromo-9,9-dimethyl-9,10-dihydroacridine and sodium hydride, add anhydrous N,N-dimethylformamide under nitrogen atmosphere, stir at room temperature until the solution changes from pale yellow to gray and no bubbles emerge; then add anhydrous N,N-dimethylformamide containing 4,4'-difluorodiphenyl sulfone dropwise, and heat to react; after the reaction is complete, extract and separate the lower organic phase, add anhydrous sodium sulfate to dry, evaporate to dryness, add silica gel powder, use a mixed solvent of petroleum ether and ethyl acetate as eluent, column chromatography, evaporate to dryness to obtain a white solid, then recrystallize and vacuum dry to obtain intermediate 10,10'-(sulfonylbis(4,1-phenylene))bis(2-bromo-9,9-dimethyl-9,10-dihydroacridine); Step 2: The intermediates 10,10'-(sulfonylbis(4,1-phenylene))bis(2-bromo-9,9-dimethyl-9,10-dihydroacridine), 2-(benzothiazol-2-yl)-4-(4,4,5,5-tetramethyl-1,3,2-dioxolane-2-yl)phenol and tetra(triphenylphosphine)palladium were mixed, and potassium carbonate, potassium fluoride, toluene and tetrahydrofuran were added under nitrogen atmosphere. The mixture was heated to reflux and reacted. After the reaction was completed, the solvent was removed by pressure distillation, and the lower organic phase was extracted and separated. Anhydrous sodium sulfate was added for drying, and after rotary drying, silica gel powder was added. A mixed solvent of petroleum ether, dichloromethane and ethyl acetate was used as the eluent. After column chromatography, the solid was rotary dried to obtain a yellow-green solid. After recrystallization and vacuum drying, SPDDBD-1 was obtained.

10. The application of the blue fluorescent material with exciton cycling and thermal exciton properties as described in claim 1 in a single-molecule blue OLED device, characterized in that, The single-molecule blue OLED device is a multilayer structure stacked on top of each other, consisting of 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 transport layer, an electron injection layer, and a cathode layer, from bottom to top. The organic light-emitting layer is made of CBP doped with the blue fluorescent material.

Images