Small molecule material based on condensed ring tert-butyl pyrene, preparation method thereof and application of small molecule material in OLED (Organic Light Emitting Diode)

Abstract

The invention discloses a small molecule material based on condensed ring tert-butyl pyrene, a preparation method thereof and application of the small molecule material in an OLED (Organic Light Emitting Diode), and belongs to the technical field of organic photoelectric materials. The material is constructed by condensed ring tert-butyl pyrene, pyrene and carbazole are hybridized to form a novel carbazole condensed ring derivative with a large molecular conjugated structure and high stability, and the large conjugated plane structure can enhance the intermolecular stacking property, reduce the hole transport energy barrier and improve the hole mobility; due to the stereo steric effect of tert-butyl, excessive aggregation of molecules can be avoided, and charge transfer traps and non-radiative recombination are reduced; the phosphoric acid anchoring group can optimize interface bonding with the ITO anode, and the anode work function is matched to reduce the hole injection barrier. When the material is used as a core component of an OLED hole transport layer, the charge transport efficiency can be effectively improved, material crystallization and interface charge recombination in device operation can be inhibited, the brightness, efficiency and long-term stability of an OLED device can be remarkably improved, and the material has important significance in promoting the application of an OLED in the fields of high-end display and illumination.

Description

Technical Field

[0001] This invention belongs to the field of new materials technology and relates to the preparation of functional materials for organic light-emitting diodes (OLEDs). In particular, it relates to a small molecule material based on fused-ring tert-butylpyrene, its preparation method and application. Specifically, the small molecule material is used as a core component of the hole transport layer (HTL) in OLED devices, thereby improving the charge transport efficiency, thermal stability and long-term operational reliability of the devices. Background Technology

[0002] With the rapid iteration of display and lighting technologies, organic light-emitting diodes (OLEDs) have become a core technology in the next generation of displays and high-end lighting due to their outstanding advantages such as self-emission, high contrast, wide viewing angle, flexibility, and low power consumption. The performance of OLED devices hinges on the molecular design and interface matching of organic functional materials. Hole transport materials (HTMs), as key components connecting the anode and the emissive layer, directly determine the efficiency of hole injection from the anode and transport to the emissive layer, as well as the balanced recombination efficiency with electrons, thus affecting the device's brightness, efficiency, lifetime, and stability. Currently, triarylamine compounds are the most commonly used small-molecule hole transport materials for OLEDs. However, these materials generally suffer from low glass transition temperatures (Tg), insufficient molecular packing order, and susceptibility to crystallization or phase separation during long-term operation, leading to increased interfacial charge recombination and shortened lifetime. Furthermore, the matching degree between the HOMO energy levels of traditional hole transport materials and commonly used anodes still has room for optimization, and the high hole injection barrier limits device efficiency improvement. In addition, some hole transport materials exhibit poor thermal stability and are prone to thermal decomposition during device fabrication and long-term use, further impacting device reliability. Therefore, developing novel small-molecule hole transport materials with high Tg, excellent thermal stability, suitable HOMO energy levels, and efficient charge transport performance is key to breaking through the performance bottlenecks of existing OLED devices and promoting their large-scale application in high-end display and lighting fields. It has significant academic value and promising industrial application prospects. Summary of the Invention

[0003] The application aims to provide a small molecule material based on a fused ring tert-butyl pyrene, which is used as a hole transport layer core component in an OLED device, has more excellent thermal stability, stronger molecular packing characteristics and a more matched HOMO energy level compared with a traditional triarylamine hole transport material, can effectively reduce a hole injection barrier, improve hole mobility, and inhibit interface charge recombination and material phase separation during device operation, and significantly improve the brightness, efficiency and long-term stability of the OLED device.

[0004] The application is implemented by the following technical scheme. In order to achieve the above object, the application provides a small molecule material based on a fused ring tert-butyl pyrene, which has a chemical structural formula shown in formula LL01. .

[0005] In order to achieve the above object, the application provides a small molecule material based on a fused ring tert-butyl pyrene, which has a chemical structural formula shown in formula LL01. S1: substituting reaction of compound 1 and pinacol diboronic acid to generate intermediate 2;

[0006] The molar ratio of the compound 1 to the pinacol diboronic acid is 1:1.2-1.5; S2: substituting reaction of compound 2 and o-bromonitrobenzene to generate intermediate 3;

[0007] The molar ratio of the compound 2 to the o-bromonitrobenzene is 1:1.2-1.5; S3: ring closure reaction of compound 3 to generate intermediate 4;

[0008] The molar ratio of the compound 3 to the triphenylphosphine is 1:5-10; S4: substituting reaction of compound 4 and dibromobutane to generate intermediate 5;

[0009] The molar ratio of the compound 4 to the dibromobutane is 1:10-60; S5: substituting reaction of compound 5 and triethyl phosphite to generate intermediate 6;

[0010] The molar ratio of the compound 5 to triethyl phosphite is 1:5-40. S6: Compound 6 is subjected to a hydrolysis reaction to generate a target product, i.e., a small molecule material LL01.

[0011] The molar ratio of the compound 6 to bromotrimethylsilane is 1:1.2-5.

[0012] Further, in the S1, compound 1 and pinacol diboronic acid are dissolved in 1,4-dioxane, and then potassium acetate aqueous solution and dichloro[1,1'-bis(diphenylphosphino)ferrocene]palladium(II) are added, and the mixture is heated to 110-120 ℃ under an argon atmosphere for 7-8 h to obtain compound 2. Further preferably, the heating temperature is 110 ℃, 115 ℃, or 120 ℃; and the reaction time is 7 h, 7.5 h, or 8 h.

[0013] Further preferably, the molar ratio of the compound 1 to pinacol diboronic acid is 1:1.2, 1:1.3, 1:1.4, or 1:1.5.

[0014] Further, in the S2, compound 2 and o-bromonitrobenzene are dissolved in DMF, and then potassium carbonate aqueous solution and tetrakis(triphenylphosphine)palladium are added, and the mixture is heated to 140-160 ℃ under an argon atmosphere for 6-8 h to prepare compound 3, and compound 3 is separated and purified after the reaction is completed. Further preferably, the heating temperature is 140 ℃, 150 ℃, or 160 ℃; and the reaction time is 6 h, 7 h, or 8 h.

[0015] Further preferably, the molar ratio of the compound 2 to o-bromonitrobenzene is 1:1.2, 1:1.3, 1:1.4, or 1:1.5.

[0016] Further, in the S3, compound 3 and triphenylphosphine are mixed in o-dichlorobenzene, and the mixture is subjected to a ring-closing reaction under an argon atmosphere at 180-200 ℃ for 10-24 h to obtain compound 4 after the reaction is completed. Further preferably, the heating temperature is 180 ℃, 190 ℃, or 200 ℃; and the reaction time is 10 h, 11 h, 12 h, 13 h, 14 h, 15 h, 16 h, 17 h, 18 h, 19 h, 20 h, 21 h, 22 h, 23 h, or 24 h.

[0017] Further preferably, the molar ratio of the compound 3 to triphenylphosphine is 1:5, 1:6, 1:7, 1:8, 1:9, or 1:10.

[0018] Further, in the S4, compound 4 is dissolved in dibromobutane, and then TBAB and potassium hydroxide aqueous solution are added, and heated to 60-80 DEG C, and reacted for 4-8 h to obtain compound 5. Further preferably, the heating temperature is 60 DEG C, 70 DEG C, 80 DEG C; and the reaction time is 4 h, 5 h, 6 h, 7 h, 8 h.

[0019] Further preferably, the molar ratio of compound 4 to dibromoalkane is 1:10, 1:20, 1:30, 1:40, 1:50, 1:60.

[0020] Further, in the S5, compound 5 is heated to 100-200 DEG C with triethyl phosphite under argon atmosphere, and reacted for 8-20 h to obtain compound 6, and then separated and purified to obtain compound 6. Further preferably, the reaction temperature is 100 DEG C, 110 DEG C, 120 DEG C, 130 DEG C, 140 DEG C, 150 DEG C, 160 DEG C, 170 DEG C, 180 DEG C, 190 DEG C, 200 DEG C; and the reaction time is 8 h, 9 h, 10 h, 11 h, 12 h, 13 h, 14 h, 15 h, 16 h, 17 h, 18 h, 19 h, 20 h.

[0021] Further preferably, the molar ratio of compound 5 to triethyl phosphite is 1:5, 1:10, 1:15, 1:20, 1:25, 1:30, 1:35, 1:40.

[0022] Further, in the S6, compound 6 is mixed with trimethylsilyl bromide in 1,4-dioxane, and hydrolysis reaction occurs under argon atmosphere, and reacted for 10-24 h at 25-100 DEG C, and then 1,4-dioxane is distilled out under reduced pressure, and then methanol and water are added to quench the reaction, and then filtered to obtain the target product LL01. Further preferably, the reaction temperature is 25 DEG C, 30 DEG C, 40 DEG C, 50 DEG C, 60 DEG C, 70 DEG C, 80 DEG C, 90 DEG C, 100 DEG C; and the reaction time is 10 h, 11 h, 12 h, 13 h, 14 h, 15 h, 16 h, 17 h, 18 h, 19 h, 20 h, 21 h, 22 h, 23 h, 24 h.

[0023] Further preferably, the molar ratio of compound 6 to trimethylsilyl bromide is 1:1.2, 1:1.5, 1:2, 1:2.5, 1:3, 1:3.5, 1:4, 1:4.5, 1:5.

[0024] In a third aspect, the application provides a use of the above-mentioned fused-ring small-molecule material in an organic light-emitting diode.

[0025] The beneficial effects of the present application are: 1. The small molecule material based on fused ring tert-butyl pyrene provided by the present application is a hole transport material for OLED devices, and the large conjugate plane structure constructed by the base fused ring tert-butyl pyrene can reduce the hole transport energy barrier through the electron delocalization effect, significantly optimize the hole migration performance, and perform better than the traditional triarylamine hole transport material; the tert-butyl group on the base can regulate the stacking mode of the molecule on the ITO substrate through the steric hindrance effect, avoid the blockage of the charge transport channel caused by excessive aggregation, and reduce the trap state density and non-radiative recombination loss. At the same time, the phosphoric acid anchoring group in the molecule can realize firm combination with the ITO anode, the HOMO level is highly matched with the ITO work function, the hole injection barrier is effectively reduced, the injection efficiency of the hole from the anode to the hole transport layer is improved, and key support is provided for efficient charge transport of the OLED device.

[0026] 2. The application of the small molecule material based on fused ring tert-butyl pyrene provided by the present application in the OLED device exhibits excellent thermal stability and device performance synergy. The thermogravimetric analysis test shows that the thermal decomposition temperature of the material is significantly higher than that of the traditional hole transport material, and can withstand the heat accumulation in the vacuum evaporation and long-term operation process of the OLED device; the glass transition temperature is high, which can effectively inhibit the crystallization and phase separation of the material in the device operation, and reduce the interface defects. This characteristic not only guarantees the structural stability of the OLED device in the preparation and long-term use process, but also further optimizes the brightness, efficiency and lifetime of the device by reducing the interface charge recombination, and provides strong support for the stable application of OLED in the high-end display and lighting field. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 The nuclear magnetic hydrogen spectrum of formula LL01 prepared by the present application; Figure 2 The liquid ultraviolet test graph of formula LL01 prepared by the present application, the test shows that the material has characteristic absorption peaks at 250-450 nm, indicating that the molecular large π conjugate system is good, the electron delocalization is good, which lays a foundation for low-energy barrier hole transport, and compared with the traditional triarylamine material, it is more conducive to improving the charge transport efficiency; Figure 3 The thermogravimetric analysis test graph of formula LL01 prepared by the present application; Figure 4 The organic light emitting diode structure schematic diagram made of the material of example 1; wherein, from bottom to top, it is glass substrate, hole injection layer, hole transport layer, light emitting layer, electron transport layer, electron injection layer and cathode, and the 5% thermal decomposition temperature of the material is 350 DEG C, the glass transition temperature is high, and the material can withstand the vacuum evaporation and long-term operation heat; the brightness and efficiency of the device are significantly improved, the crystallization and phase separation of the material in the long-term operation are inhibited, the interface defects are reduced, and the reliability of the device is guaranteed. DETAILED DESCRIPTION

[0028] Based on the above description, the present application provides a small molecule material based on fused ring tertiary butyl pyrene, and also provides a preparation method and application of the material. The present application prepares a novel carbazole fused ring derivative by hybridizing pyrene and carbazole, and the molecular conjugated structure is large and the molecular structure is stable, which is conducive to improving the stability of the OLED device. Since the molecule has a large conjugated planar structure, it has strong stacking property, which is conducive to improving the interface charge transport efficiency of the hole transport layer and the adjacent functional layer of the OLED device, and also can effectively promote the hole migration and inhibit the interface charge recombination in the non-target area. Therefore, the small molecule material based on the fused ring tertiary butyl pyrene is a kind of photoelectric material with excellent performance. When it is applied to the OLED device as a hole transport material, good device performance can be obtained. The present application will be described in detail in combination with specific embodiments. Example 1

[0029] The present embodiment method synthesizes a small molecule layer hole transport material, and the chemical formula is formula LL01

[0030] The specific synthesis route is as follows:

[0031]

[0032] Synthesis of compound 2: Compound 1 (1-bromo-7-fused ring tertiary butyl pyrene, 1.88 g, 5.57 mmol) and bis(pinacolato)diboron (1.70 g, 6.69 mmol) were dissolved in 1,4-dioxane, and then 50% potassium acetate aqueous solution (6 eq) and dichloro[1,1'-bis(diphenylphosphino)ferrocene]palladium(II) (0.41 g, 0.35 mmol) were added. The reaction mixture was stirred at 120°C for 7 hours. After the reaction was completed, the mixture was extracted with dichloromethane, and the organic layer was dried with anhydrous sodium sulfate. The crude product was purified by column chromatography (eluent: petroleum ether / dichloromethane = 9:1) to obtain 1.57 g of white solid product (yield 73%).

[0033] The structure characterization data of compound 2 is as follows: 1 H NMR (400 MHz, CDCl3) δ 9.06 (d, J = 9.2Hz, 1H), 8.53 (d, J= 7.7 Hz, 1H), 8.29 – 8.24 (m, 2H), 8.19 – 8.10 (m, 3H),8.07 (d, J = 8.9 Hz, 1H), 1.62 (s, 9H), 1.53 (s, 12H). Synthesis of compound of formula 3: Compound 2 (1.57 g, 4.06 mmol) was dissolved in N,N-dimethylformamide along with 1-bromo-2-nitrobenzene (1.07 g, 5.28 mmol) followed by addition of 50% aqueous potassium carbonate solution (8 eq) and tetrakis(triphenylphosphine)palladium (0.47 g, 0.41 mmol). The reaction was stirred at 140 °C for 7 h. After completion of the reaction, the mixture was extracted with dichloromethane and the organic layer was dried over anhydrous sodium sulfate. The crude product was purified by column chromatography (eluent: petroleum ether / dichloromethane = 5:2) to obtain the product as yellow oil 1.09 g (yield 70%).

[0034] The structural characterization data of compound of formula 3 are: 1 H NMR (400 MHz, CDCl3) δ 8.32 – 8.23 (m,3H), 8.17 – 8.10 (m, 2H), 8.06 (dd, J = 9.3, 1.5 Hz, 1H), 8.01 – 7.90 (m,2H), 7.41 – 7.31 (m, 2H), 7.01 (td, J = 7.4, 1.1 Hz, 1H), 6.94 (dd, J = 7.9,1.1 Hz, 1H), 1.64 (s, 9H). Synthesis of compound of formula 4: Compound 3 (1.09 g, 2.86 mmol) and triphenylphosphine (3.75 g, 14.29 mmol) were dissolved in o-dichlorobenzene and the reaction mixture was stirred at 190 °C for 18 h. After completion of the reaction, the mixture was extracted with dichloromethane and the organic layer was dried over anhydrous sodium sulfate. The solvent was removed under reduced pressure. The crude product was purified by column chromatography (eluent: petroleum ether / dichloromethane = 5:1) to obtain the product as yellow solid 0.69 g (yield 70%).

[0035] The structural characterization data of compound of formula 4 are: 1 H NMR (400 MHz, DMSO-d6) δ 12.02 (s, 1H),9.12 (dd, J= 9.2, 3.4 Hz, 1H), 8.83 (d, J = 8.0 Hz, 1H), 8.41 (s, 1H), 8.36(d, J = 9.1 Hz, 1H), 8.32 (q, J = 1.8 Hz, 2H), 8.26 – 8.21 (m, 1H), 8.13 –8.07 (m, 1H), 7.79 (d, J = 8.0 Hz, 1H), 7.60 (t, J = 7.6 Hz, 1H), 7.42 (t, J = 7.5 Hz, 1H), 1.53 (s, 9H). Synthesis of compound of formula 5: Compound 4 (0.69 g, 1.99 mmol) was dissolved in 1,4-dibromobutane (19.30 g, 10.7 mL, 89.36 mmol) and tetrabutylammonium bromide (0.13 g, 0.40 mmol) and 50% aqueous potassium hydroxide solution (100 eq) were added successively. The mixture was stirred at 80 °C for 6 h. After completion of the reaction, the mixture was extracted with dichloromethane and the organic layer was dried over anhydrous sodium sulfate and the solvent was removed under reduced pressure. The crude product was purified by column chromatography (eluent: petroleum ether: dichloromethane = 3: 1 mixture solvent) to obtain the product as a yellow solid 0.79 g (yield 82%).

[0036] The structural characterization data of compound of formula 5 are: 1 H NMR (400 MHz, DMSO- d 6) δ 9.10 (dd, J =9.3, 3.1 Hz, 1H), 8.84 (d, J = 8.1 Hz, 1H), 8.48 (s, 1H), 8.40 – 8.30 (m,3H), 8.26 – 8.17 (m, 1H), 8.14 – 8.08 (m, 1H), 7.80 (d, J = 8.2 Hz, 1H), 7.60(t, J = 7.7 Hz, 1H), 7.42 (t, J = 7.5 Hz, 1H), 4.64 (t, J = 7.0 Hz, 2H), 3.50– 3.45 (m, 2H), 1.98 (p, J= 7.0 Hz, 2H), 1.90 – 1.81 (m, 2H), 1.53 (s, 9H). Synthesis of compound of formula 6: Compound 5 (0.79 g, 1.64 mmol) was dissolved in triethyl phosphite (10.88 g, 11.34 mL, 65.49 mmol) and the reaction mixture was heated at 170 °C for 8 h. After completion of the reaction, the solvent was removed under reduced pressure. The crude product was purified by column chromatography (eluent: petroleum ether: ethyl acetate = 1:1 mixture solvent) to obtain the product as yellow green oil 0.79 g (yield 90%).

[0037] The compound of formula 6 was characterized by the following data: 1 H NMR (400 MHz, DMSO- d 6) δ 9.19 (d, J = 9.2 Hz, 1H), 8.92 (d, J = 8.0 Hz, 1H), 8.57 (s, 1H), 8.46 (d, J = 9.2 Hz, 1H), 8.41 (d, J = 1.9 Hz, 1H), 8.39 – 8.35 (m, 1H), 8.25 (d, J = 9.1 Hz, 1H), 8.16 (d, J = 9.1 Hz, 1H), 7.90 (d, J = 8.1 Hz, 1H), 7.64 (ddd, J = 8.2, 7.1, 1.1 Hz, 1H), 7.45 (t, J = 7.2 Hz, 1H), 4.74 (t, J = 7.0 Hz, 2H), 3.92 – 3.80 (m, 4H), 2.01 (d, J = 11.8 Hz, 2H), 1.58 (s, 10H), 1.20 (dt, J = 18.8, 7.1 Hz, 3H), 1.10 (t, J = 7.1 Hz, 6H). Synthesis of compound of formula LL01: Compound 6 (0.79 g, 1.46 mmol) was dissolved in dry 1,4-dioxane (6 mL) under argon and bromotrimethylsilane (1.3 eq, 1.90 mL, 1.9 mmol) was added dropwise. The reaction mixture was stirred at room temperature under nitrogen for 24 hours. The solvent was then removed under reduced pressure and the remaining liquid was dissolved in methanol (5 mL). Distilled water (50 mL) was then added dropwise to the solution until it became turbid. The product was collected by filtration and washed with water to give the green solid product 0.69 g (97% yield).

[0038] attached Figure 1 The structure of the compound of formula LL01 prepared in the present application is characterized by the following nuclear magnetic hydrogen spectrum: 1 HNMR (400 MHz, DMSO- d 6) δ 9.18 (d, J = 9.1 Hz, 1H), 8.91 (d, J = 8.0 Hz, 1H),8.56 (d, J = 1.3 Hz, 1H), 8.45 (d, J = 9.0 Hz, 1H), 8.41 (d, J = 1.8 Hz, 1H),8.36 (d, J = 1.9 Hz, 1H), 8.26 (dd, J = 9.1, 2.4 Hz, 1H), 8.15 (d, J = 9.0Hz, 1H), 7.89 (dd, J = 8.5, 2.0 Hz, 1H), 7.64 (t, J = 7.6 Hz, 1H), 7.45 (t, J = 7.4 Hz, 1H), 4.72 (td, J = 7.2, 3.4 Hz, 3H), 3.90 – 3.77 (m, 1H), 2.02 (t, J = 7.2 Hz, 2H), 1.65 (d, J = 7.8 Hz, 2H), 1.57 (s, 9H), 1.10 (t, J = 7.0 Hz,2H). Example 2

[0039] Unlike Example 1, in this example, in Step S1, heating was performed at 110 °C under argon atmosphere for 7 h to obtain compound 2. Example 3

[0040] Unlike Example 1 and Example 2, in this example, in Step S1, heating was performed at 115 °C under argon atmosphere for 7.5 h to obtain compound 2. Example 4

[0041] Unlike Example 1, in this example, in Step S2, heating was performed at 160 °C under argon atmosphere for 6 h to obtain compound 3. Example 5

[0042] Unlike Example 1 and Example 4, in this example, in Step S2, heating was performed at 150 °C under argon atmosphere for 8 h to obtain compound 3. Example 6

[0043] Unlike Example 1, in this example, in Step S3, heating was performed at 180 °C under argon atmosphere for 24 h to obtain compound 4. Example 7

[0044] Unlike Example 1 and Example 6, in this example, in Step S3, heating was performed at 200 °C under argon atmosphere for 10 h to obtain compound 4. Example 8

[0045] Unlike Example 1, in this example, in Step S4, heating was performed at 60 °C under argon atmosphere for 8 h to obtain compound 5. Example 9

[0046] Unlike Example 1 and Example 8, in this example, in Step S4, heating was performed at 70 °C under argon atmosphere for 4 h to obtain compound 5. Example 10

[0047] Unlike Example 1, in this example, in Step S5, heating was performed at 100 °C under argon atmosphere for 20 h to obtain compound 6. Example 11

[0048] Unlike Example 1 and Example 10, in this example, in Step S5, heating was performed at 200 °C under argon atmosphere for 15 h to obtain compound 6. Example 12

[0049] Unlike Example 1, in this example, in Step S6, heating was performed at 100 °C under argon atmosphere for 10 h to obtain the target product LL01. Example 13

[0050] Unlike Examples 1 and 12, in step S6 of this example, the target product LL01 is obtained by heating to 70°C in an argon atmosphere and reacting for 20 h.

[0051] Figure 2 The UV spectrum of the liquid LL01 prepared by this invention is shown. The test shows that the material has characteristic absorption peaks in the 250-450 nm range, indicating that the molecular large π conjugation system is good and the electron delocalization is excellent, which lays the foundation for low-barrier hole transport. Compared with traditional triarylamine materials, it is more conducive to improving charge transport efficiency.

[0052] Appendix Figure 3 The thermogravimetric analysis (TGA) results of the LL01 prepared according to the present invention are shown, indicating that the 5% thermal decomposition temperature of this material is as high as 350 °C, demonstrating excellent thermal stability.

[0053] Appendix Figure 4 The OLED device structure based on the small molecule material tert-butylpyrene of the present invention consists of, from bottom to top, a glass substrate, a hole injection layer, a hole transport layer (the material of the present invention), a light-emitting layer, an electron transport layer, an electron injection layer, and a cathode. Its 5% thermal decomposition temperature reaches 350°C, exhibiting excellent thermal stability. Furthermore, it can effectively suppress material crystallization and phase separation, reduce interface defects, and significantly improve device brightness, efficiency, and long-term operational reliability.

[0054] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. The provided embodiments do not cover all options of the technical solution of the present invention. It is clear that the reactant ratio, reaction temperature, reaction time, and other conditions in each step of the technical solution of the present invention can be arbitrarily selected within the scope defined by the technical solution of the present invention, and the results will be the same as those in the above embodiments, all of which can solve the technical problem of the present invention and achieve the same technical effect. All equivalent transformations or modifications made according to the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A fused-ring tert-butylpyrene-based small molecule material characterized in that, A chemical structural formula shown in formula LL01: 。 2. The method of claim 1, wherein the method of preparing a fused ring tertiary butyl pyrene-based small molecule material is characterized by, The method comprises the following steps: S1: substituting compound 1 with pinacol diborane to generate intermediate compound 2; The molar ratio of the compound 1 to the pinacol diborane is 1:1.2-1.5; S2: substituting compound 2 with o-bromonitrobenzene to generate intermediate compound 3; The molar ratio of the compound 2 to the o-bromonitrobenzene is 1:1.2-1.5; S3: ring-closing compound 3 to generate intermediate compound 4; The molar ratio of the compound 3 to the triphenylphosphine is 1:5-10; S4: substituting compound 4 with dibromobutane to generate intermediate compound 5; The molar ratio of the compound 4 to the dibromobutane is 1:10-60; S5: substituting compound 5 with triethyl phosphite to generate intermediate compound 6; The molar ratio of the compound 5 to the triethyl phosphite is 1:5-40; S6: hydrolyzing compound 6 to generate a target product, i.e., a small-molecule material LL01; The molar ratio of the compound 6 to the bromotrimethylsilane is 1:1.2-5.

3. The method for preparing a small molecule material based on fused-ring tert-butylpyrene according to claim 2, characterized in that: In the S1, compound 1 and pinacol diborane are dissolved in 1,4-dioxane, then potassium acetate aqueous solution and dichloro[1,1'-bis(diphenylphosphino)ferrocene]palladium(II) are added, and the mixture is heated to 110-120 DEG C under an argon atmosphere for 7-8 h to obtain compound 2.

4. The method for preparing a small molecule material based on fused-ring tert-butylpyrene according to claim 2, characterized in that: In the S2, compound 2 and o-bromonitrobenzene are dissolved in DMF, then potassium carbonate aqueous solution and tetrakis(triphenylphosphine)palladium are added, and the mixture is heated to 140-160 DEG C under an argon atmosphere for 6-8 h to prepare compound 3, and compound 3 is obtained after separation and purification.

5. The method for preparing a small molecule material based on fused-ring tert-butylpyrene according to claim 2, characterized in that: In the S3, compound 3 and triphenylphosphine are mixed in o-dichlorobenzene, and the mixture is subjected to ring-closing reaction under an argon atmosphere, and is heated to 180-200 DEG C for 10-24 h to obtain compound 4 after separation and purification.

6. The method for preparing a small molecule material based on fused-ring tert-butylpyrene according to claim 2, characterized in that: In the S4, compound 4 is dissolved in dibromobutane, then TBAB and potassium hydroxide aqueous solution are added, and the mixture is heated to 60-80 DEG C for 4-8 h to obtain compound 5.

7. The method for preparing a small molecule material based on fused-ring tert-butylpyrene according to claim 2, characterized in that: In the S5, compound 5 and triethyl phosphite are heated to 100-200 DEG C under an argon atmosphere for 8-20 h to prepare compound 6, and compound 6 is obtained after separation and purification.

8. The method of claim 2, wherein the method is characterized by: In the S6, compound 6 and bromotrimethylsilane are mixed in 1,4-dioxane, and the mixture is subjected to hydrolysis reaction under an argon atmosphere, and is heated to 25-100 DEG C for 10-24 h, 1,4-dioxane is distilled out under reduced pressure after the reaction is completed, methanol and water are added in sequence to quench the reaction, and the target product LL01 is obtained after filtration.

9. Application of the small-molecule material based on the fused-ring tert-butyl pyrene in claim 1 to an organic light-emitting diode.

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