Preparation method and application of a kind of binfluorene oxepin chrysene fluorescent material

Abstract

The application discloses a preparation method and application of a binuclear spirofluorene-oxyxanthene-based griffiths fluorescent material, and [binuclear spirofluorene-oxyxanthene-fluorobenzene]-based griffiths (G-DSFX) is synthesized by adopting a C-H bond activation griffiths method. The optimal reaction condition is screened as follows: a catalyst is Pd(OAc), a ligand is PtBu2Me-HBF4, a base is K2CO3, a solvent is DMAc, a temperature is 120 DEG C, a reaction time is 48 h, and a reaction concentration is 20 mmol / L ‑1 , and a yield is up to 19%. OLED is prepared by adopting a solution processing method, I-shape, U-shape, m-shape and G-DSFX are used as OLED light-emitting layers to test the devices, and the turn-on voltages are 3.9 V, 6.9 V, 4.5 V and 6.4 V respectively; the maximum luminances are 67.9 cd / m ‑2 , 56.69 cd / m ‑2 , 45.43 cd / m ‑2 and 72.2 cd / m ‑2 respectively; and the maximum external quantum efficiencies EQEmax are 0.08%, 0.06%, 0.03% and 0.15% respectively, which proves that the griffiths strategy can also improve the luminance and external quantum efficiency of the device, and provides a reference for preparing OLED by adopting the solution processing method.

Description

Technical Field

[0001] This invention belongs to the field of organic electroluminescent devices, and particularly relates to a method for preparing and applying a spirofluoreneoxanthracene chromarylene fluorescent material. Background Technology

[0002] To date, spirofluorene-based organic semiconductors have shown great potential in the field of organic optoelectronics. However, the commercialization of organic devices faces challenges such as expensive raw materials and cumbersome preparation processes, making green organic semiconductors an important solution. In 2006, we proposed a one-pot method for spirofluorene-xanthracene (SFX), which overcomes the problems of lengthy routes and expensive raw materials in the preparation of spirocyclic aromatic hydrocarbons. This method also improves the quantum efficiency of light-emitting devices, enhances the thermal and photoelectric stability of materials, exhibits strong molecular modifiability, and enables industrial-scale production. Due to these advantages, SFX has been widely used in the field of organic optoelectronics.

[0003] Through continuous exploration, various SFX-derived materials have been developed. Among them, fused two spirofluorene xanthracene units form bis-spirofluorene xanthracene (DSFX). The positions of the two spirorings are fixed by the rigid xanthracene framework, and the close distance between them promises high luminous efficiency and high electron transport. In 2019, we successfully synthesized bis-spirofluorene xanthracene lattice (GS-SFX) using DSFX as the core building block, and theoretical calculations verified that its electronic properties and recombination energy have reached the good performance indicators of hole transport materials. In 2023, we developed a flexible deep blue light-emitting material based on DSFX, namely polyoxanthracene spirofluorene, which provides an effective strategy for the development of flexible light-emitting displays. These studies fully affirm the role of DSFX in regulating the photoelectric properties of materials.

[0004] Currently, commercial OLEDs (organic light-emitting diodes) are prepared using the vapor deposition method. However, the vapor deposition process requires stringent conditions, has a raw material utilization rate of only 30%, and relies heavily on imported vapor deposition equipment. Therefore, developing solution-based OLED preparation is an inevitable trend. Based on this, this invention utilizes a CH bond activation strategy to synthesize [spirofluoreneoxanthracene-fluorobenzene] alkylarene, characterizes its photoelectric properties, and applies it to OLEDs (organic light-emitting diodes) prepared using the solution processing method. Summary of the Invention

[0005] Based on the above analysis, the purpose of this invention is to synthesize a novel spirofluorenexanthracene lattice aromatic hydrocarbon fluorescent material, investigate the influence of the lattice effect on the material's properties, characterize the material's photoelectric properties, explore its application in OLED device fabrication, and further verify that the lattice strategy can effectively improve the brightness and efficiency of the device, providing important reference and guidance for the further development of organic light-emitting materials. This invention is achieved through the following technical means:

[0006] This invention first provides a spirofluoreneoxanthracene lattice aromatic hydrocarbon fluorescent material, the structural formula of which is as follows: in: It is a class of spirofluorene compounds;

[0007] Choose from any of the following structures:

[0008]

[0009] Choose from any of the following structures:

[0010]

[0011] X mentioned herein is any one of F, Cl, Br, I, CH3, NO2, and CH3O.

[0012] Furthermore, the R on the alkyl chain is a straight chain, including: a hydrogen atom, an alkane chain, an alkoxy chain, and an alkyl chain with a halogen atom terminally introduced with fluorine, chlorine, or bromine, as shown in the following specific structure:

[0013] -HC n H 2n+1 -OC n H 2n+1 -C n H 2n+1 FC n H 2n+1 Cl-C n H 2n+1 Br.

[0014] Furthermore, the aforementioned type of spirofluorene compound The specific structural formula is as follows:

[0015]

[0016] This invention also discloses a method for preparing a spirofluorenexanthracene lattice aromatic hydrocarbon fluorescent material, which is synthesized through a CH bond activation lattice method, specifically including the following steps:

[0017] At a reaction temperature of 80-150℃, a U-shaped synthon (U-shape), a base of dibromospirofluoroxanthracene (DBrDSFX), ligands, an organic solvent, and a palladium catalyst were added and reacted for 36-72 h. The reaction concentration of the reaction system was 20 mmol·L-1, and the molar ratio of the U-shaped synthon (U-shape) to dibromospirofluoroxanthracene (DBrDSFX) was 1:1, finally yielding a cyclophosphine fluorescent material.

[0018] Furthermore, the alkali is selected from one or a combination of two of potassium carbonate, potassium hydroxide, sodium carbonate, and sodium bicarbonate;

[0019] The ligand is selected from one or a combination of two of the following: PtBu2Me-HBF4, phosphoramide ligands, 1,1'-binaphthyl-2,2'-bisdiphenylphosphine (BINAP), and JosiPhos;

[0020] Furthermore, the organic solvent is selected from one or a combination of two of N,N-dimethylformamide, dimethyl sulfoxide, toluene, and acetonitrile.

[0021] Furthermore, the palladium catalyst is selected from one or more combinations of tetra(triphenylphosphine)palladium, palladium acetate, palladium neopentanoate, palladium trifluoroacetate, palladium diphenylphosphine ferrocene dichloride, palladium dichloroditriphenylphosphine, or palladium on carbon.

[0022] Furthermore, the palladium catalyst is palladium acetate.

[0023] Furthermore, the amount of palladium acetate used is determined according to the reactivity of different substrates, and the amount of palladium acetate is 0.025 to 0.05 times that of the synthon.

[0024] Furthermore, the reaction temperature is 120°C and the reaction time is 48 hours.

[0025] The present invention also discloses a spirofluoreneoxane-based chromarylene fluorescent material prepared according to any of the above preparation methods.

[0026] The present invention also discloses the application of the above-mentioned spirofluoreneoxane-based chromarylene fluorescent material in electroluminescent devices.

[0027] Furthermore, the electroluminescent device is an organic light-emitting diode.

[0028] The beneficial effects of this invention are as follows:

[0029] 1. This invention focuses on the synthesis, properties, and applications of [spirofluorenoxanthracene-fluorobenzene] alkylarenes. First, retrosynthetic analysis confirmed that the stepwise method is also applicable to [spirofluorenoxanthracene-fluorobenzene] alkylarenes. Furthermore, we screened the optimal reaction conditions for the alkylarene G-DSFX: a reaction temperature of 120℃, a reaction time of 48 h, palladium acetate as a catalyst (0.025–0.05 times the amount of the synthon), PtBu2Me-HBF4 as a ligand, K2CO3 as a base, an organic solvent selected from one or a combination of two of N,N-dimethylformamide, dimethyl sulfoxide, toluene, and acetonitrile, and a reaction concentration of 20 mmol·L⁻¹. -1 The yield can reach up to 19%.

[0030] 2. To investigate the effect of the lattice effect on material properties, the photoelectric properties of the material were characterized. Spectroscopic results show ( Figure 2 In solution, compared to the linear m-shape, the maximum absorption wavelength of lattice-based G-DSFX exhibits a blue shift of 11 nm and a maximum emission wavelength of 3 nm. In thin film, the maximum absorption wavelength is blue-shifted by 13 nm and the maximum emission wavelength by 14 nm. Furthermore, the PLQY of G-DSFX is significantly improved in solution compared to the m-shape, while it is drastically reduced in thin film. This indicates that aggregation quenching is more severe in [spirofluorenexanthracene-fluorobenzene] lattice aromatics, leading to a decrease in the luminescence efficiency of G-DSFX. Additionally, electrochemical measurements show that the band gaps of the m-shape and G-DSFX are 4.11 eV and 3.88 eV, respectively, with a slight decrease in the molecular band gap after lattice formation.

[0031] 3. Application research was conducted using them as OLED light-emitting layers. Test results showed ( Figure 4 The linear molecule m-shape and the lattice G-DSFX both have low start-up voltages of 2.5V and 6.4V, respectively. The maximum luminance of G-DSFX is approximately 1.5 times that of m-shape. Furthermore, G-DSFX has a current efficiency 4 times higher than m-shape and a power efficiency 8 times higher, with an EQE... max 5 times higher than m-shape ( Figure 5 These findings further validate that the lattice strategy can effectively improve the brightness and efficiency of devices, providing important reference and guidance for the further development of organic light-emitting materials. Attached Figure Description

[0032] Figure 1 The diagram shows the structural confirmation of G-DSFX, where (a) represents the DBrDSFX mass spectrum; (b) represents the U-shape mass spectrum; (c) represents the G-DSFX mass spectrum; and (d) represents the substrate DBrDSFX, U-shape, and lattice G-DSFX. 1 H NMR stacked spectrum.

[0033] Figure 2Photophysical characterization of G-DSFX is shown in (a) for I-shape, U-shape, m-shape and G-DSFX in solution; (b) for I-shape, U-shape, m-shape and G-DSFX in thin film; (c) for fluorescence lifetime of I-shape, U-shape, m-shape and G-DSFX in different states; and (d) for photoluminescence quantum yield of I-shape, U-shape, m-shape and G-DSFX in solution and thin film.

[0034] Figure 3 The CV diagrams are for I-shape, U-shape, m-shape, and G-DSFX; where (a) is the electrochemical oxidation and reduction performance diagram of I-shape, U-shape, m-shape, and G-DSFX; and (b) is the energy level diagram of I-shape, U-shape, m-shape, and G-DSFX.

[0035] Figure 4 The current density / brightness / voltage relationship of OLEDs fabricated for G-DSFX is shown in the following figures: 4a: JVL curves and efficiency curves for I-shape; 4b: CE and PE for I-shape as a function of current density; 4c: JVL curves and efficiency curves for U-shape; 4d: CE and PE for U-shape as a function of current density; 4e: JVL curves and efficiency curves for m-shape; 4f: CE and PE for m-shape as a function of current density; 4g: JVL curves and efficiency curves for G-DSFX; 4h: CE and PE for G-DSFX as a function of current density.

[0036] Figure 5 (a) represents the EL spectra of I-shape, U-shape, m-shape and G-DSFX devices; (b) represents the EQE of I-shape, U-shape and m-shape devices; (c) represents the EQE of G-DSFX devices.

[0037] Figure 6 This is a structural diagram of the OLED device from G-DSFX.

[0038] Figure 7 The synthesis route for the U-shape.

[0039] Figure 8 The synthesis route for G-DSFX. Detailed Implementation

[0040] To make the objectives, technical solutions, and effects of this invention clearer and more explicit, the invention and accompanying drawings are further described in detail below. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0041] Where specific experimental steps or conditions are not specified in the examples, they can be performed according to the conventional experimental steps or conditions described in the literature in this field. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0042] Example 1

[0043] Dibromospirofluorene xanthracene DBrDSFX

[0044] The structural formula of the product is as follows:

[0045]

[0046] All necessary instruments for the reaction, including the three-necked reaction flask, magnetic stir bar, and condenser, should be thoroughly cleaned and dried in an oven beforehand. First, connect and secure the reaction flask and condenser, sealing the opening with a rubber stopper and wrapping the apparatus with aluminum foil to ensure light protection. Then, completely seal the connection points with sealing film, leaving one opening unsealed. Next, accurately weigh the solid reagents 2-bromo-9-fluorenone (2.580 g, 1 equiv), resorcinol (1.650 g, 1.5 equiv), and toluenesulfonic acid (5.660 g, 5 equiv) and add them to the reaction flask. After all reagents have been added, seal the final opening with a rubber stopper and sealing film. Then, evacuate the reaction apparatus and purge with nitrogen three times, securing it with a nitrogen balloon for protection. Next, add 60 ml of toluene solvent to the reaction flask using a syringe, sealing the needle hole with vacuum grease to prevent leakage. Finally, transfer the apparatus to an oil bath, set the temperature to 120°C, and reflux for 24 hours. The reaction was monitored using a TLC plate. After the reaction was complete, the heating function of the oil bath was turned off. Once the reaction had cooled to room temperature, 8.280 g of K₂CO₃ (2 equiv) and 5.160 g of 1-bromooctane (3 equiv) were weighed and added to the reaction flask, and the apparatus was sealed again. The oil bath heating function was then turned on, and the temperature was set to 120°C. The reaction was stopped after reflux for 24 hours. After the reaction had cooled to room temperature, toluene was removed from the reaction solution using a rotary evaporator. The solution was then extracted multiple times with dichloromethane, stirred using a rotary evaporator, and purified using a 30 cm high chromatography column filled with 100-200 mesh silica gel powder. Eluent was used to elute with a [petroleum ether:dichloromethane = 10:1] solution to obtain a white solid product. This product was then further purified by recrystallization using a dichloromethane / methanol mixed solvent, with a yield of 4%. 1HNMR (400MHz, CDCl3): δ7.48(d,J=7.7Hz,2H), 7.38(d,J=8.1Hz,2H), 7.32(d,J=1.7Hz,1H), 7.30(d,J=1.8Hz,1H), 7.18(td,J=7.5 ,1.1Hz,2H), 7.07(d,J=1.7Hz,2H), 7.05(s,1H), 7.02(t,J=8.0Hz,1H), 6.88(d,J=7.6Hz,2H), 6.74(d,J=2.5Hz,2H), 5.32(s,1H); 13 C NMR (101MHz, CDCl3) δ159.1,155.9,153.4,152.2,151.2,138.2,137.7,130.6,128.1,127.9,127.4, 126.6,125.1,121.4,120.8,120.5,119.4,115.9,111.0,104.3,101.8,77.2,76.8,76.5,68.0,53.5.

[0047] Example 2

[0048] U-shaped synthonU-shape

[0049] The structural formula of the product is as follows:

[0050]

[0051] All instruments required for the reaction, including the Schlenk reaction flask and magnetic stir bar, should be thoroughly cleaned and dried in an oven beforehand. First, fix the reaction flask on an iron stand and wrap the apparatus with aluminum foil to ensure it is protected from light. Next, accurately weigh the solid reagents DBrDSFX (0.200 g, 1 equiv), K2CO3 (0.055 g, 2 equiv), and P... tBu2Me-HBF4 (0.010 g, 0.2 equiv) and Pd(OAc)2 (0.045 g, 0.1 equiv) were added to the reaction tube, followed by 1,2,4,5-tetrafluorobenzene (0.600 g, 20 equiv) and DMAc solvent (2.5 ml) using a syringe. After all the solvent was added, the reaction apparatus was evacuated and purged with nitrogen three times, and the stopper was tightened under nitrogen. Finally, the apparatus was transferred to an oil bath and refluxed at 110 °C for 48 h to stop the reaction. After the reaction cooled to room temperature, the high-boiling-point solvent DMAc was removed by multiple extractions with ethyl acetate / water. Then, the sample was mixed using a rotary evaporator, and separated and purified using a 25cm high chromatography column packed with 200-300 mesh silica gel powder. The product was eluted with a polar eluent of [petroleum ether: dichloromethane = 8:1] to obtain a white solid product, which could be further purified by recrystallization with a dichloromethane / n-hexane mixed solvent, with a yield of 84%. 1 H NMR (400MHz, CDCl3) δ7.64(d,J=7.9Hz,2H), 7.55(d,J=7.5Hz,2H), 7.18(t,J=7.4Hz,2H), 7.07–6.95( m,8H), 6.85(q,J=8.3Hz,2H), 6.72(s,2H), 6.32(d,J=8.5Hz,2H), 6.21(d,J=8.8Hz,2H), 5.46(s,1H); 13 C NMR (101MHz, CDCl3) δ159.6,155.7,154.3,152.7,151.7,141.4,138.1,130.0,129.1,128.6,127.9,127.7,127.2,126.9,125.5,121.9 ,121.8,121.7,121.1,120.5,120.0,116.8,111.6,107.7,104.8,104.6,104.3,103.8,102.3,77.8,77.8,77.5,77.2,76.8,76.6,68.6.

[0052] Example 3

[0053] [spirofluoroxanthracene-fluorobenzene] ligaryl aromatics G-DSFX

[0054] The structural formula of the product is as follows:

[0055]

[0056] All instruments required for the reaction, including the Schlenk reaction flask and magnetic stir bar, were thoroughly cleaned and dried in an oven beforehand. First, the reaction flask was fixed to an iron stand, and the apparatus was wrapped in aluminum foil to ensure protection from light. Next, the solid reagents U-shape (0.262 g, 1 equiv), DBrDSFX (0.200 g, 1 equiv), K₂CO₃ (0.055 g, 2 equiv), and P were accurately weighed. t Bu2Me-HBF4 (0.010 g, 0.2 equiv) and Pd(OAc)2 (0.045 g, 0.1 equiv), along with DMAc solvent (6 ml) drawn into a syringe, were added to the reaction tube. After all reagents and solvents were added, the reaction apparatus was evacuated and purged with nitrogen three times, with the stopper tightened under nitrogen. Finally, the apparatus was transferred to an oil bath at 120°C and refluxed for 48 hours to terminate the reaction. After the reaction cooled to room temperature, the high-boiling-point solvent DMAc was removed by multiple extractions with ethyl acetate / water. The sample was stirred using a rotary evaporator, and the product was separated and purified using a 25 cm high chromatography column packed with 200-300 mesh silica gel powder. Eluent with a polarity of [petroleum ether: dichloromethane: acetone = 60:6:1] was used to elute, yielding a white solid product. This product could be further purified by recrystallization from a dichloromethane / n-hexane mixed solvent, with a yield of 19%. 1 HNMR(400MHz, CDCl3) δ7.70(d,J=8.0Hz,4H), 7.57(d,J=7.6Hz,4H), 7.19–6.95(m,22H) , 6.71(d,J=2.5Hz,4H), 6.28(dd,J=8.7,2.6Hz,4H), 6.17(d,J=8.7Hz,4H), 5.63(s,1H); 13 C NMR (101MHz, CDCl3) δ157.9,157.3,150.9,150.4,144.7,143.9,143.4,141.0,140.3,140.2, 140.2,138.8,137.3,136.0,135.8,133.5,130.6,130.4,129.9,129.4,128.0,127.6,127.3,1 27.1,126.8,126.5,126.5,126.1,125.9,125.9,125.5,125.3,125.1,124.9,124.7,123.9,1224,119.4,119.2,113.1,109.9,100.6,91.7,82.4,76.2,76.0,75.8,75.5,70.1,66.9,66.8.

[0057] Example 4

[0058] Type I synthonI-shape

[0059] The structural formula of the product is as follows:

[0060]

[0061] All instruments required for the reaction, including the Schlenk reaction flask and magnetic stir bar, should be thoroughly cleaned and dried in an oven beforehand. First, fix the reaction flask on an iron stand and wrap the apparatus with aluminum foil to ensure light protection. Next, accurately weigh the solid reagents 2-bromospirofluoreneoxanthracene 2-BrSFX (0.198 g, 3 equiv), K₂CO₃ (0.048 g, 2 equiv), and P… t Bu2Me-HBF4 (0.005 g, 0.2 equiv) and Pd(OAc)2 (0.002 g, 0.1 equiv) were added to the reaction tube, along with 1,2,4,5-tetrafluorobenzene (0.015 g, 1 equiv) and solvent DMAc (2 ml) using a syringe. After all reagents and solvents were added, the apparatus was evacuated and purged with nitrogen three times, and the stopper was tightened under nitrogen. Finally, the apparatus was transferred to an oil bath at 140°C and refluxed for 24 hours to stop the reaction. After the reaction cooled to room temperature, the high-boiling-point solvent DMAc was removed by multiple extractions with ethyl acetate / water. The sample was stirred using a rotary evaporator, and the product was separated and purified using a 25 cm high chromatography column packed with 100-200 mesh silica gel powder. The product was eluted with a polar eluent of [petroleum ether: dichloromethane = 10:1] to obtain a white solid product in 85% yield. 1 HNMR (400MHz, CDCl3) δ7.87 (d, J = 7.9 Hz, 2H), 7.80 (d, J = 7.6 Hz, 2H), 7.46 (d, J = 8.1 Hz, 2H), 7.37 (t, J = 8.0 Hz, 2H), 7.23 (d,J=11.0Hz,4H), 7.16(d,J=7.5Hz,2H), 6.71(d,J=2.4Hz,4H), 6.37(dd,J=8.7,2.5Hz,4H), 6.32(s,2H), 6.30(s,2H); 13 C NMR (101MHz, CDCl3) δ158.0,154.8,154.5,151.1,139.6,137.6,128.7,127.9,127.5,1 26.7,126.6,126.1,124.6,119.2,118.9,115.1,110.0,100.7,76.3,76.0,75.7,67.1.

[0062] Example 5

[0063] m-type synthon m-shape

[0064]

[0065] All instruments required for the reaction, including the Schlenk reaction flask and magnetic stir bar, should be thoroughly cleaned and dried in an oven beforehand. First, fix the reaction flask on an iron stand and wrap the apparatus with aluminum foil to ensure it is protected from light. Next, accurately weigh the solid reagents DBrDSFX (0.100g, 1 equiv), K2CO3 (0.048g, 2 equiv), and P... t Bu2Me-HBF4 (0.005 g, 0.2 equiv) and Pd(OAc)2 (0.002 g, 0.1 equiv) were added to the reaction tube, followed by 1,2,4,5-tetrafluorobenzene (0.015 g, 1 equiv) and solvent DMAc (3 ml) using a syringe. After all reagents and solvents were added, the apparatus was evacuated and purged with nitrogen three times, and the stopper was tightened under nitrogen. Finally, the apparatus was transferred to an oil bath at 120°C and refluxed for 48 hours to stop the reaction. After the reaction cooled to room temperature, the high-boiling-point solvent DMAc was removed by multiple extractions with ethyl acetate / water. Then, the sample was mixed using a rotary evaporator, and separated and purified using a 30cm high chromatography column packed with 100-200 mesh silica gel powder. The product was eluted with a polar eluent of [petroleum ether: dichloromethane = 10:1] to obtain a white solid product, which could be further purified by recrystallization with a dichloromethane / n-hexane mixed solvent, with a yield of 85%. 1 H NMR (400MHz, CDCl3) δ7.62 (q, J=7.6, 6.0Hz, 4H), 7.55 (d, J=7.6Hz, 4H), 7.18 (t, J=7.7Hz, 8H), 7.09–6.92(m,14H), 6.79–6.64(m,4H), 6.43(d,J=7.2Hz,2H), 6.38–6.16(m,8H), 5.45(s,2H); 13 C NMR (101MHz, CDCl3) δ157.3,154.2,151.6,150.4,149.2,136.6,135.9,128.8,126.3,126.0 ,125.6,124.8,123.3,119.6,119.0,118.7,117.6,114.2,109.2,102.5,100.0,66.2,51.7.

[0066] Application Example 1

[0067] Using solution processing, I-shape, U-shape, m-shape, and G-DSFX were used as OLED emissive layers for device testing. The specific device structure was ITO transparent conductive substrate / PEDOT:PSS (40nm) / organic emissive layer (≈40nm) / TPBi (40nm) / LiF (1nm) / Al (100nm). The test results are as follows: Figure 4 and 5 :

[0068] according to Figure 4 The results show that: the I-shape has a start-up voltage of 3.9V, and when the voltage reaches 8.9V, the current density is 71.13mA·cm⁻², achieving a maximum brightness of 67.9cd·m⁻²; the U-shape has a start-up voltage of 6.9V, and when the voltage reaches 10.9V, the current density is 97.37mA·cm⁻², achieving a maximum brightness of 56.69cd·m⁻²; while the m-shape has a start-up voltage of 4.5V, and when the voltage reaches 10.9V, the current density is 110.2mA·cm⁻², achieving a maximum brightness of 45.43cd·m⁻². Similarly, the G-DSFX has a start-up voltage of 6.4V, and when the voltage reaches 9.4V, the current density is 38.13mA·cm⁻², achieving a maximum brightness of 72.2cd·m⁻².

[0069] Figure 4 Figures b, 4d, 4f, and 4h illustrate the relationship between current density (CE) and current protection (PE) for their respective current-to-current ratios. As shown in the figures, the maximum current efficiency for the I-shape is 0.12 cd·A⁻¹, and the maximum power efficiency is 0.06 lm·W⁻¹; the maximum current efficiency for the U-shape is 0.08 cd·A⁻¹, and the maximum power efficiency is 0.3 lm·W⁻¹; the maximum current efficiency for the m-shape is 0.05 cd·A⁻¹, and the maximum power efficiency is 0.01 lm·W⁻¹; while the maximum current efficiency for the G-DSFX is 0.22 cd·A⁻¹, and the maximum power efficiency is 0.08 lm·W⁻¹.

[0070] according to Figure 5 The results show that the maximum emission wavelengths of I-shape, U-shape, m-shape and G-DSFX are 432nm, 428nm, 436nm and 416nm, respectively. Figure 4 bc corresponds to their EQE. It can be seen that the EQEmax of I-shape, U-shape, m-shape and G-DSFX are 0.08%, 0.06%, 0.03% and 0.15%, respectively. It can be seen that in [spirofluoreneoxane-fluorobenzene] lattice aromatics, the lattice strategy can also improve the brightness and external quantum efficiency of the device.

[0071] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A spirofluoreneoxanthracene lattice aromatic hydrocarbon fluorescent material, the structural formula of which is as follows: ;in: It is a class of spirofluorene compounds; Choose from any of the following structures: ； Choose from any of the following structures: ； ， X mentioned herein is any one of F, Cl, Br, I, CH3, NO2, and CH3O; The group of R is -H or -OC8H. 17； The aforementioned class of spirofluorene compounds The specific structure is as follows: 。 2. A method for preparing the spirofluorenexanthracene lattice aromatic hydrocarbon fluorescent material as described in claim 1, which is synthesized via a CH bond activation lattice method, comprising: The reaction was carried out at a temperature of 80-150℃, with the addition of the U-shape synthon, the dibromospirofluoroxanthracene (DBrDSFX) base, ligand, organic solvent, and palladium catalyst for 36-72 h. The reaction concentration of the system was 20 mmol·L⁻¹. -1 The molar ratio of the U-shape synthon to dibromospirofluoroxanthracene (DBrDSFX) is 1:1, ultimately yielding a dibromofluoroxanthracene methyl latrine fluorescent material.

3. The preparation method according to claim 2, wherein: The alkali is selected from one or a combination of two of potassium carbonate, potassium hydroxide, sodium carbonate, and sodium bicarbonate. The ligand is selected from one or a combination of two of the following: PtBu2Me-HBF4, phosphoramide ligands, 1,1'-binaphthyl-2,2'-bisdiphenylphosphine, and JosiPhos; The organic solvent is selected from one or a combination of two of N,N-dimethylformamide, dimethyl sulfoxide, toluene, and acetonitrile; The palladium catalyst is selected from one or more combinations of tetra(triphenylphosphine)palladium, palladium acetate, palladium neopentanoate, palladium trifluoroacetate, diphenylphosphine ferrocene palladium dichloride, dichloroditriphenylphosphine palladium, or palladium on carbon.

4. The preparation method according to claim 3, wherein: The palladium catalyst is palladium acetate.

5. The preparation method according to claim 3, wherein: The amount of palladium acetate is 0.025 to 0.05 times that of U-shape.

6. The preparation method according to claim 2, wherein: The reaction temperature was 120℃ and the reaction time was 48 h.

7. A spirofluoreneoxane-based chromarylene fluorescent material prepared by the preparation method according to any one of claims 2 to 6.

8. The application of the spirofluoreneoxanthracene chromarylene fluorescent material according to claim 7 in an electroluminescent device, wherein: The electroluminescent device is an organic light-emitting diode.

Images