CN107879984A - One kind buries in oblivion organic blue light small molecule and its application of mechanism based on triplet state-triplet state - Google Patents

Abstract

One kind buries in oblivion the blue-fluorescence small molecule of phenanthro- imidazoles-anthracene derivant of mechanism and its application in high efficiency non-doping electric electroluminescence device is prepared based on triplet state-triplet state, belongs to technical field of organic electroluminescence.It is prepared more particularly to preparing phenanthro- imidazoles raw material from phenanthrenequione one kettle way and being connected phenanthro- imidazoles with anthracene using Suzuki couplings.Phenanthro- imidazoles is connected with anthryl group by suitable mode, is effectively buried in oblivion by triplet state-triplet state using Triplet exciton, and introduces cyano group enhancing intermolecular interaction, is further improved triplet state-triplet state and is buried in oblivion efficiency, lifts device overall performance.Undoped blue-light device is 1000cd m in brightness in the present invention^‑2When external quantum efficiency be 9.44%, efficiency roll-off is small, and cut-in voltage is low, realizes high efficiency under high illumination, is the blue-light device leading level in the world.The compound of the present invention is significant for filling up the undoped blue-light device of current high efficiency this blank, there is important application prospect in total colouring and white-light illuminating.

Description

A small organic blue light molecule based on triplet-triplet annihilation mechanism and its application

technical field

The invention belongs to the technical field of organic electroluminescence, and specifically relates to a class of blue fluorescent small molecules of phenanthrene imidazole-anthracene derivatives based on a triplet-triplet annihilation mechanism and their application in the preparation of high-efficiency non-doped OLEDs devices .

Background technique

In 1987, Dr. Deng Qingyun of Kodak Company (Organic electroluminescent diodes, CW Tang and SAVan Slyke, Appl. Phys. Lett., 1987, 51 913-915.) invented a high-efficiency organic thin-film electroluminescent device, which has become popular all over the world. It has set off an upsurge of research on OLEDs materials and devices. In the past three decades, OLEDs have developed rapidly and corresponding commercial products have been applied to display and lighting. However, there are still many unresolved issues in this field hindering the further commercialization of OLEDs. In OLEDs devices, the ratio of singlet and triplet excitons is 1:3. Traditional organic fluorescent small molecules can only use 25% of singlet excitons, and the remaining 75% are triplet excitons due to transition prohibition. Device efficiency is low. Metal complex phosphorescent materials based on iridium (Ir) or platinum (Pt) can allow spin-forbidden triplet states to emit light directly and realize 100% exciton utilization. Recently popular thermally activated delayed fluorescence (TADF) materials (Highlyefficient organic light-emitting diodes from delayed fluorescence", H.Uoyama, K.Goushi, K.Shizu, H.Nomura, C.Adachi, Nature, 2012,492,234-240 ), in the absence of noble metals, through reasonable molecular design, the energy level difference between singlet and triplet states (ΔE _ST ) is reduced, and effective reverse intersystem crossing (RISC) from triplet to singlet is realized, which can also reach The purpose of 100% utilization of excitons. However, whether it is metal complex phosphorescent materials or TADF materials, there is a serious problem of device efficiency attenuation under high brightness. Due to the triplet to singlet spin prohibition, for metal complex phosphorescent materials For TADF materials, the speed of the triplet radiative transition to the singlet ground state is very slow; for TADF materials, the speed of triplet reverse intersystem crossing to the singlet excited state is very slow. This will lead to a very long lifetime of the triplet state. In In the actual working process of the device, as the current density increases, the generated triplet excitons have no time to rapidly radiatively transition to the ground state or reverse intersystem crossing to the singlet excited state, resulting in a large accumulation of triplet excitons in the device, which will Annihilated by various non-radiative interactions, resulting in a serious efficiency roll-off at high brightness, which is not conducive to the practical application of the material. And it is precisely because the triplet to singlet spin flipping speed is very slow, metal complex phosphorescent materials and TADF materials Both need to be doped into a suitable matrix to alleviate the triplet state quenching problem caused by self-aggregation. This requires selecting a suitable matrix material and finely adjusting the doping concentration, which will make the device structure more complicated and increase the actual application cost .Blue light is essential in full-color display and white lighting, and metal complex phosphorescent materials and TADF materials have their own limitations in achieving blue light emission. Therefore, the development of non-doped devices that can maintain high brightness High-efficiency organic fluorescent small molecule materials are of great significance and will play an important role in promoting the further popularization of OLEDs technology.

Triplet-triplet (TTA) annihilation is based on the mechanism of two triplet excitons colliding with each other to generate a singlet state, which can effectively convert triplet excitons into singlet states for light emission, and can overcome the concentration of triplet excitons The efficiency roll-off problem caused by too high, because in theory, the greater the concentration of triplet excitons, the greater the probability of two triplet excitons colliding with each other, and the more effective the use of triplet excitons through the TTA mechanism. Both phenanthroimidazole and anthracene are high-efficiency blue-light chromophores, and both can efficiently utilize triplet excitons through the TTA mechanism. The phenanthroimidazole and anthracene are connected in a reasonable way, and the intermolecular interaction is enhanced by introducing cyano (CN), which further improves the efficiency of TTA, thereby improving the overall performance of the device.

Contents of the invention

The purpose of the present invention is to provide a class of high-efficiency organic blue light small molecules suitable for non-doped devices. This type of material can realize the effective utilization of triplet excitons through an effective TTA mechanism, and can achieve high efficiency under high brightness. It overcomes the shortcomings of metal complex phosphorescent materials and TADF materials that must be doped and the device efficiency is seriously attenuated under high brightness.

Another object of the present invention is to provide the application of the above-mentioned material as a light-emitting layer in the preparation of non-doped blue OLEDs.

According to the present invention, a small organic blue light molecule based on phenanthrene imidazole-anthracene derivative has a structural formula as shown in P1n or P2n:

Wherein Ar represents the aromatic group shown in the following structural formula:

Preferably, the above-mentioned small organic blue light molecule based on phenanthroimidazole-anthracene derivatives has a structural formula as shown in one of P ₁ -P ₈ :

The above-mentioned organic blue-light small molecule based on phenanthroimidazole-anthracene derivatives is prepared by preparing the phenanthroimidazole raw material from phenanthrenequinone in one pot and connecting phenanthromidazole and anthracene by Suzuki coupling.

An organic electroluminescence device prepared based on the above-mentioned organic blue light small molecule, which is composed of a glass substrate, an ITO anode, a hole transport layer, a light-emitting layer, an electron transport layer and a cathode, and is characterized in that the light-emitting layer contains at least one of the present invention The organic blue light small molecule.

The principle of the invention is: phenanthroimidazole and anthracene are high-efficiency blue light chromophores, and can effectively utilize triplet excitons through the TTA mechanism, breaking through the exciton statistics of 25% singlet generation rate of traditional organic fluorescent small molecules. The TTA mechanism is based on the collision of two triplet states to generate a singlet state. Within a certain range of triplet concentration, the higher the triplet concentration, the more effective TTA is, so it can maintain high device efficiency under high brightness, and can be used in The non-doped device is beneficial to simplify the device structure, reduce the manufacturing cost of the device, and overcome the serious efficiency roll-off problem of metal complex phosphorescent materials and TADF materials under high brightness. In addition, the introduction of cyano groups can enhance the interaction between molecules, which is beneficial to improve the efficiency of TTA, thereby further improving the overall performance of non-doped devices. Finally, through appropriate chemical synthesis methods, phenanthroimidazoles can have multiple different reaction sites, which is beneficial to realize the diversification of material structures.

The organic blue light small molecule luminescent material and organic electroluminescent device of the present invention have the following advantages and beneficial effects:

(1) The structure of the organic fluorescent small molecule of the present invention is single and definite, the synthesis is simple, the purification is convenient, it is convenient to study the relationship between structure and performance, and it is beneficial to industrial scale-up production.

(2) The organic fluorescent small molecule of the present invention has good thermal stability, and the vapor-deposited film is flat and uniform without obvious phase separation, and is suitable for non-doped OLEDs devices based on vapor-deposition technology.

(3) The organic fluorescent small molecule of the present invention has a higher HOMO energy level and a lower LUMO energy level, which is beneficial to the balanced injection and transport of carriers.

(4) The device efficiency of the non-doped blue OLEDs prepared by the organic fluorescent small molecule of the present invention has a small roll-off, a low turn-on voltage, and shows a higher device efficiency under high brightness. It is the international leading level of Blu-ray devices. The compound of the invention is of great significance for filling the blank of current high-efficiency non-doped blue light devices, and has important application prospects in full-color display and white light illumination.

Description of drawings

Figure 1 is the differential scanning calorimetry curve of P1, the melting point (T _m ) is 344 ° C, no phase transition or glass transition temperature is observed;

Figure 2 is the thermogravimetric curve of P1, the glass transition temperature (T _g ) is 483°C;

Figure 3 is the solvation emission spectrum. The compound exhibits localized state emission without obvious solvation effect, and the main luminescent peak red shifts from 434nm in the non-polar solvent n-hexane to 446nm in the polar solvent acetonitrile;

Figure 4 is the absorption and emission spectra of the non-doped evaporated film. The main peaks of the absorption spectrum are located at: 265nm, 326nm, 365nm, 381nm and 404nm; the main peak of the emission spectrum is located at 463nm;

Figure 5 is the current density-voltage-brightness curve of the non-doped electroluminescent device, the device can work normally; the maximum brightness is 57787cd m ^-2 , and the turn-on voltage is 3.0V;

Fig. 6 is the external quantum efficiency curve of the non-doped electroluminescent device, and the maximum external quantum efficiency is 9.44%. Inset: Electroluminescence spectrum at 7V driving voltage, the main peak of the spectrum is at 470nm;

Fig. 7 is the electroluminescent spectrum of the non-doped electroluminescent device under different voltages, the main peak of the spectrum is located at 470nm, and the electroluminescent spectrum is very stable under different driving voltages.

Detailed ways

Example 1

The preparation of the present embodiment _P1 comprises the following preparation steps:

Synthesis of _M1 : _M1 was prepared by Suzuki coupling. In a 100mL round bottom flask, 9,10-dibromoanthracene (5mmol, 1.67g), 4-cyanophenylboronic acid (5mmol, 735mg), tetrakistriphenylphosphine palladium (0.1mmol, 115mg) were dissolved in 40mL of toluene and 20 mL of potassium carbonate aqueous solution (2.0 mol L ^-1 ), stirred and refluxed at 90°C for 24 hours under nitrogen protection. After the reaction was completed, it was extracted with dichloromethane, the extract was concentrated by rotary evaporation, and separated by column chromatography (petroleum ether:dichloromethane=3:1, volume ratio) to obtain a light yellow-green solid (710 mg, yield: 40%). Mass spectrum MALDI-TOF (m/z) [M ⁺ ]: The measured value is 357.87, and the theoretical value is 357.02.

Synthesis of _M2 : _M2 was prepared by a one-pot method. In a 250mL round bottom flask, 9,10-phenanthrenequinone (20mmol, 4.16g), 4-bromobenzaldehyde (20mmol, 3.68g), aniline (100mmol, 9.5mL), and ammonium acetate (80mmol, 6.16g) were dissolved in In 150mL of glacial acetic acid, stirred and refluxed at 120°C for 4 hours under nitrogen protection. After the reaction was completed, the reaction system was poured into 100 mL of ice water, and a large amount of precipitates appeared instantly. After suction filtration, the obtained solid was separated and purified by column chromatography (petroleum ether:dichloromethane=1:1, volume ratio) to obtain a white-brown solid (8.05 g, yield: 90%). Mass spectrum MALDI-TOF (m/z) [M ⁺ ]: The measured value is 448.67, and the theoretical value is 448.06.

Synthesis of _M3 : _M3 was prepared by Suzuki coupling. In a 100mL round bottom flask, M ₂ (5mmol, 2.24g), pinacol diborate (10mmol, 2.54g), potassium acetate (15mmol, 1.47g), [1,1'-bis(diphenylphosphine base) ferrocene]palladium dichloride (0.1mmol, 73mg) was dissolved in 60mL of dioxane, stirred and refluxed at 90°C for 24 hours under nitrogen protection. After the reaction, extract with dichloromethane, concentrate the extract by rotary evaporation, and separate by column chromatography (petroleum ether:dichloromethane=1:2, volume ratio) to obtain a white-brown solid (1.48g, yield: 60%). Mass Spectrum MALDI-TOF (m/z) [M ⁺ ]: The measured value is 497.03, and the theoretical value is 496.23.

Synthesis of _P1 : _P1 was prepared by Suzuki coupling. In a 100mL round bottom flask, M ₁ (5mmol, 1.78g), M ₃ (5mmol, 2.48g), tetrakistriphenylphosphine palladium (0.1mmol, 115mg) were dissolved in 40mL of toluene and 20mL of aqueous potassium carbonate (2.0mol L ^-1 ), stirred and refluxed at 90°C for 24 hours under nitrogen protection. After the reaction, extract with dichloromethane, concentrate the extract by rotary evaporation, and separate by column chromatography (petroleum ether:dichloromethane=1:2, volume ratio) to obtain a light green solid (2.26g, yield: 70%). The product is further raised by sublimation. Mass Spectrum MALDI-TOF (m/z) [M ⁺ ]: The measured value is 648.11, and the theoretical value is 647.24. Elemental analysis (%) C48H29N3: theoretical value C 89.00, H 4.51, N 6.49; test value C 89.03, H 4.49, N 6.48.

Example 2

The preparation of present embodiment P ₂ comprises the following preparation steps:

Synthesis of _M4 : _M4 was prepared by a one-pot method. In a 250mL round bottom flask, 9,10-phenanthrenequinone (20mmol, 4.16g), p-tert-butylbenzaldehyde (20mmol, 3.34mL), 4-bromoaniline (100mmol, 17.20g), ammonium acetate (80mmol, 6.16 g) Dissolve in 150 mL of glacial acetic acid, stir and reflux at 120° C. for 4 hours under nitrogen protection. After the reaction was completed, the reaction system was poured into 100 mL of ice water, and a large amount of precipitates appeared instantly. After suction filtration, the resulting solid was separated and purified by column chromatography (petroleum ether:dichloromethane=1:1, volume ratio) to obtain a white-brown solid (9.05 g, yield: 90%). Mass spectrum MALDI-TOF (m/z) [M ⁺ ]: The measured value is 505.08, and the theoretical value is 504.12.

Synthesis of _M5 : _M5 was prepared by Suzuki coupling. In a 100mL round bottom flask, M ₄ (5mmol, 2.52g), pinacol diborate (10mmol, 2.54g), potassium acetate (15mmol, 1.47g), [1,1'-bis(diphenylphosphine base) ferrocene]palladium dichloride (0.1mmol, 73mg) was dissolved in 60mL of dioxane, stirred and refluxed at 90°C for 24 hours under nitrogen protection. After the reaction, extract with dichloromethane, concentrate the extract by rotary evaporation, and separate by column chromatography (petroleum ether:dichloromethane=1:2, volume ratio) to obtain a white-brown solid (1.65 g, yield: 60%). Mass spectrum MALDI-TOF (m/z) [M ⁺ ]: The measured value is 552.93, and the theoretical value is 552.29.

Synthesis of _P2 : _P2 was prepared by Suzuki coupling. In a 100mL round bottom flask, M ₁ (5mmol, 1.78g), M ₅ (5mmol, 2.76g), tetrakistriphenylphosphine palladium (0.1mmol, 115mg) were dissolved in 40mL of toluene and 20mL of aqueous potassium carbonate (2.0mol L ^-1 ), stirred and refluxed at 90°C for 24 hours under nitrogen protection. After the reaction, extract with dichloromethane, concentrate the extract by rotary evaporation, and separate by column chromatography (petroleum ether:dichloromethane=1:2, volume ratio) to obtain a light green solid (2.46g, yield: 70%). The product is further raised by sublimation. Mass spectrum MALDI-TOF (m/z) [M ⁺ ]: The measured value is 704.22, and the theoretical value is 703.30. Elemental analysis (%) C48H29N3: theoretical value C 88.73, H 5.30, N 5.97; test value C 88.75, H 5.29, N 5.96

Example 3

The preparation of present embodiment P ₃ comprises the following preparation steps:

Synthesis of _M6 : _M6 was prepared by a one-pot method. In a 250mL round bottom flask, 9,10-phenanthrenequinone (20mmol, 4.16g), 4-bromobenzaldehyde (20mmol, 3.68g), 4-bromoaniline (100mmol, 17.20g), ammonium acetate (80mmol, 6.16g ) was dissolved in 150 mL of glacial acetic acid, stirred and refluxed at 120° C. for 4 hours under nitrogen protection. After the reaction was completed, the reaction system was poured into 100 mL of ice water, and a large amount of precipitates appeared instantly. After suction filtration, the resulting solid was separated and purified by column chromatography (petroleum ether:dichloromethane=1:1, volume ratio) to obtain a white-brown solid (9.47 g, yield: 90%). Mass spectrum MALDI-TOF (m/z) [M ⁺ ]: The measured value is 526.54, and the theoretical value is 525.97.

Synthesis of _M7 : _M7 was prepared by Suzuki coupling. In a 100mL round bottom flask, M ₆ (5mmol, 2.63g), pinacol diborate (10mmol, 2.54g), potassium acetate (15mmol, 1.47g), [1,1'-bis(diphenylphosphine base) ferrocene]palladium dichloride (0.1mmol, 73mg) was dissolved in 60mL of dioxane, stirred and refluxed at 90°C for 24 hours under nitrogen protection. After the reaction, extract with dichloromethane, concentrate the extract by rotary evaporation, and separate by column chromatography (petroleum ether:dichloromethane=1:2, volume ratio) to obtain a white-brown solid (1.25 g, yield: 40%). Mass spectrum MALDI-TOF (m/z) [M ⁺ ]: The measured value is 623.77, and the theoretical value is 622.32.

Synthesis of _P3 : _P3 was prepared by Suzuki coupling. In a 100mL round bottom flask, M ₁ (5mmol, 1.78g), M ₇ (5mmol, 3.11g), tetrakistriphenylphosphine palladium (0.1mmol, 115mg) were dissolved in 40mL of toluene and 20mL of aqueous potassium carbonate (2.0mol L ^-1 ), stirred and refluxed at 90°C for 24 hours under nitrogen protection. After the reaction, extract with dichloromethane, concentrate the extract by rotary evaporation, and separate by column chromatography (petroleum ether:dichloromethane=1:2, volume ratio) to obtain a light green solid (3.23g, yield: 70%). The product is further raised by sublimation. Mass Spectrum MALDI-TOF (m/z) [M ⁺ ]: The measured value is 925.08, and the theoretical value is 924.33. Elemental analysis (%) C48H29N3: theoretical value C 89.59, H 4.36, N 6.06; test value C 89.61, H 4.34, N 6.05

Example 4

The preparation of present embodiment _P4 comprises the following preparation steps:

Synthesis of _M8 : _M8 was prepared by a one-pot method. In a 250mL round bottom flask, 2,7-dibromophenanthrenequinone (20mmol, 7.28g), p-tert-butylbenzaldehyde (20mmol, 3.34mL), aniline (100mmol, 9.5mL), ammonium acetate (80mmol, 6.16g ) was dissolved in 150 mL of glacial acetic acid, stirred and refluxed at 120° C. for 4 hours under nitrogen protection. After the reaction was completed, the reaction system was poured into 100 mL of ice water, and a large amount of precipitates appeared instantly. After suction filtration, the resulting solid was separated and purified by column chromatography (petroleum ether:dichloromethane=1:1, volume ratio) to obtain a white-brown solid (10.48 g, yield: 90%). Mass spectrum MALDI-TOF (m/z) [M ⁺ ]: The measured value is 583.15, and the theoretical value is 582.03.

Synthesis of _M9 : _M9 was prepared by Suzuki coupling. In a 100mL round bottom flask, M ₈ (5mmol, 2.91g), pinacol diborate (10mmol, 2.54g), potassium acetate (15mmol, 1.47g), [1,1'-bis(diphenylphosphine base) ferrocene]palladium dichloride (0.1mmol, 73mg) was dissolved in 60mL of dioxane, stirred and refluxed at 90°C for 24 hours under nitrogen protection. After the reaction, extract with dichloromethane, concentrate the extract by rotary evaporation, and separate by column chromatography (petroleum ether:dichloromethane=1:2, volume ratio) to obtain a white-brown solid (1.36g, yield: 40%). Mass spectrum MALDI-TOF (m/z) [M ⁺ ]: The measured value is 678.92, and the theoretical value is 678.38.

Synthesis of _P4 : _P4 was prepared by Suzuki coupling. In a 100mL round bottom flask, M ₁ (5mmol, 1.78g), M ₉ (5mmol, 3.39g), tetrakistriphenylphosphine palladium (0.1mmol, 115mg) were dissolved in 40mL of toluene and 20mL of aqueous potassium carbonate (2.0mol L ^-1 ), stirred and refluxed at 90°C for 24 hours under nitrogen protection. After the reaction, extract with dichloromethane, concentrate the extract by rotary evaporation, and separate by column chromatography (petroleum ether:dichloromethane=1:2, volume ratio) to obtain a light green solid (3.43g, yield: 70%). The product is further raised by sublimation. Mass Spectrum MALDI-TOF (m/z) [M ⁺ ]: The measured value is 981.43, and the theoretical value is 980.39. Elemental analysis (%) C48H29N3: theoretical value C 89.36, H 4.93, N 5.71; test value C 89.33, H 4.95, N 5.72

Example 5

The preparation of present embodiment _P5 comprises the following preparation steps:

Synthesis of M ₁₀ : M ₈ was prepared by a one-pot method. In a 250mL round bottom flask, 3,6-dibromophenanthrenequinone (20mmol, 7.28g), p-tert-butylbenzaldehyde (20mmol, 3.34mL), aniline (100mmol, 9.5mL), ammonium acetate (80mmol, 6.16g ) was dissolved in 150 mL of glacial acetic acid, stirred and refluxed at 120° C. for 4 hours under nitrogen protection. After the reaction was completed, the reaction system was poured into 100 mL of ice water, and a large amount of precipitates appeared instantly. After suction filtration, the resulting solid was separated and purified by column chromatography (petroleum ether:dichloromethane=1:1, volume ratio) to obtain a white-brown solid (10.48 g, yield: 90%). Mass spectrum MALDI-TOF (m/z) [M ⁺ ]: The measured value is 583.74, and the theoretical value is 582.03.

Synthesis of M ₁₁ : M ₁₁ was prepared by Suzuki coupling. In a 100mL round bottom flask, M ₁₀ (5mmol, 2.91g), pinacol diborate (10mmol, 2.54g), potassium acetate (15mmol, 1.47g), [1,1'-bis(diphenylphosphine base) ferrocene]palladium dichloride (0.1mmol, 73mg) was dissolved in 60mL of dioxane, stirred and refluxed at 90°C for 24 hours under nitrogen protection. After the reaction, extract with dichloromethane, concentrate the extract by rotary evaporation, and separate by column chromatography (petroleum ether:dichloromethane=1:2, volume ratio) to obtain a white-brown solid (1.36g, yield: 40%). Mass spectrum MALDI-TOF (m/z) [M ⁺ ]: the measured value is 679.21, and the theoretical value is 678.38.

Synthesis of _P5 : _P5 was prepared by Suzuki coupling. In a 100mL round bottom flask, M ₁ (5mmol, 1.78g), M ₁₁ (5mmol, 3.39g), tetrakistriphenylphosphine palladium (0.1mmol, 115mg) were dissolved in 40mL of toluene and 20mL of aqueous potassium carbonate (2.0mol L ^-1 ), stirred and refluxed at 90°C for 24 hours under nitrogen protection. After the reaction, extract with dichloromethane, concentrate the extract by rotary evaporation, and separate by column chromatography (petroleum ether:dichloromethane=1:2, volume ratio) to obtain a light green solid (3.43g, yield: 70%). The product is further raised by sublimation. Mass Spectrum MALDI-TOF (m/z) [M ⁺ ]: The measured value is 981.24, and the theoretical value is 980.39. Elemental analysis (%) C48H29N3: theoretical value C 89.36, H 4.93, N 5.71; test value C 89.37, H 4.93, N 5.70

Example 6

The preparation of present embodiment P ₆ comprises the following preparation steps:

Synthesis of M ₁₂ : M ₁₂ was prepared by a one-pot method. In a 250mL round bottom flask, 9,10-phenanthrenequinone (20mmol, 4.16g), m-bromobenzaldehyde (20mmol, 3.68g), aniline (100mmol, 9.5mL), ammonium acetate (80mmol, 6.16g) were dissolved in 150mL In glacial acetic acid, stirred and refluxed at 120° C. for 4 hours under nitrogen protection. After the reaction was completed, the reaction system was poured into 100 mL of ice water, and a large amount of precipitates appeared instantly. After suction filtration, the obtained solid was separated and purified by column chromatography (petroleum ether:dichloromethane=1:1, volume ratio) to obtain a white-brown solid (8.05 g, yield: 90%). Mass spectrum MALDI-TOF (m/z) [M ⁺ ]: The measured value is 449.39, and the theoretical value is 448.06.

M ₁₃ was prepared by Suzuki coupling. In a 100mL round bottom flask, M ₁₂ (5mmol, 2.24g), pinacol diborate (10mmol, 2.54g), potassium acetate (15mmol, 1.47g), [1,1'-bis(diphenylphosphine base) ferrocene]palladium dichloride (0.1mmol, 73mg) was dissolved in 60mL of dioxane, stirred and refluxed at 90°C for 24 hours under nitrogen protection. After the reaction, extract with dichloromethane, concentrate the extract by rotary evaporation, and separate by column chromatography (petroleum ether:dichloromethane=1:2, volume ratio) to obtain a white-brown solid (1.48g, yield: 60%). Mass Spectrum MALDI-TOF (m/z) [M ⁺ ]: The measured value is 497.37, and the theoretical value is 496.23.

Synthesis of _P6 : _P6 was prepared by Suzuki coupling. In a 100mL round bottom flask, M ₁₃ (5mmol, 1.78g), M ₁ (5mmol, 2.48g), tetrakistriphenylphosphine palladium (0.1mmol, 115mg) were dissolved in 40mL of toluene and 20mL of aqueous potassium carbonate (2.0mol L ^-1 ), stirred and refluxed at 90°C for 24 hours under nitrogen protection. After the reaction, extract with dichloromethane, concentrate the extract by rotary evaporation, and separate by column chromatography (petroleum ether:dichloromethane=1:2, volume ratio) to obtain a light green solid (2.26g, yield: 70%). The product is further raised by sublimation. Mass spectrum MALDI-TOF (m/z) [M ⁺ ]: the test value is 647,91, and the theoretical value is 647.24. Elemental analysis (%) C48H29N3: theoretical value C 89.00, H 4.51, N 6.49; test value C 89.03, H 4.50, N 6.47

Example 7

The preparation of present embodiment P ₇ comprises the following preparation steps:

Synthesis of M ₁₄ : M ₁₄ was prepared by a one-pot method. In a 250mL round bottom flask, 9,10-phenanthrenequinone (20mmol, 4.16g), p-tert-butylbenzaldehyde (20mmol, 3.34mL), m-bromoaniline (100mmol, 17.20g), ammonium acetate (80mmol, 6.16g ) was dissolved in 150 mL of glacial acetic acid, stirred and refluxed at 120° C. for 4 hours under nitrogen protection. After the reaction was completed, the reaction system was poured into 100 mL of ice water, and a large amount of precipitates appeared instantly. After suction filtration, the resulting solid was separated and purified by column chromatography (petroleum ether:dichloromethane=1:1, volume ratio) to obtain a white-brown solid (9.05 g, yield: 90%). Mass spectrum MALDI-TOF (m/z) [M ⁺ ]: The measured value is 505.29, and the theoretical value is 504.12.

Synthesis of M ₁₅ : M ₁₅ was prepared by Suzuki coupling. In a 100mL round bottom flask, M ₁₄ (5mmol, 2.52g), pinacol diborate (10mmol, 2.54g), potassium acetate (15mmol, 1.47g), [1,1'-bis(diphenylphosphine base) ferrocene]palladium dichloride (0.1mmol, 73mg) was dissolved in 60mL of dioxane, stirred and refluxed at 90°C for 24 hours under nitrogen protection. After the reaction, extract with dichloromethane, concentrate the extract by rotary evaporation, and separate by column chromatography (petroleum ether:dichloromethane=1:2, volume ratio) to obtain a white-brown solid (1.65 g, yield: 60%). Mass spectrum MALDI-TOF (m/z) [M ⁺ ]: The measured value is 553.06, and the theoretical value is 552.29.

Synthesis of _P7 : _P7 was prepared by Suzuki coupling. In a 100mL round bottom flask, M ₁ (5mmol, 1.78g), M ₁₅ (5mmol, 2.76g), tetrakistriphenylphosphine palladium (0.1mmol, 115mg) were dissolved in 40mL of toluene and 20mL of aqueous potassium carbonate (2.0mol L ^-1 ), stirred and refluxed at 90°C for 24 hours under nitrogen protection. After the reaction, extract with dichloromethane, concentrate the extract by rotary evaporation, and separate by column chromatography (petroleum ether:dichloromethane=1:2, volume ratio) to obtain a light green solid (2.46g, yield: 70%). The product is further raised by sublimation. Mass spectrum MALDI-TOF (m/z) [M ⁺ ]: The measured value is 704.63, and the theoretical value is 703.30. Elemental analysis (%) C48H29N3: theoretical value C 88.73, H 5.30, N 5.97; test value C 88.71, H 5.31, N 5.98

Example 8

The preparation of present embodiment P ₈ comprises the following preparation steps:

Synthesis of M ₁₆ : M ₁₆ was prepared by a one-pot method. In a 250mL round bottom flask, dissolve 9,10-phenanthrenequinone (20mmol, 4.16g), m-bromobenzaldehyde (20mmol, 3.68g), m-bromoaniline (100mmol, 17.20g), and ammonium acetate (80mmol, 6.16g) In 150 mL of glacial acetic acid, stirred and refluxed at 120° C. for 4 hours under nitrogen protection. After the reaction was completed, the reaction system was poured into 100 mL of ice water, and a large amount of precipitates appeared instantly. After suction filtration, the resulting solid was separated and purified by column chromatography (petroleum ether:dichloromethane=1:1, volume ratio) to obtain a white-brown solid (9.47 g, yield: 90%). Mass spectrum MALDI-TOF (m/z) [M ⁺ ]: The measured value is 526.73, and the theoretical value is 525.97.

Synthesis of M ₁₇ : M ₁₇ was prepared by Suzuki coupling. In a 100mL round bottom flask, M ₁₆ (5mmol, 2.63g), pinacol diborate (10mmol, 2.54g), potassium acetate (15mmol, 1.47g), [1,1'-bis(diphenylphosphine base) ferrocene]palladium dichloride (0.1mmol, 73mg) was dissolved in 60mL of dioxane, stirred and refluxed at 90°C for 24 hours under nitrogen protection. After the reaction, extract with dichloromethane, concentrate the extract by rotary evaporation, and separate by column chromatography (petroleum ether:dichloromethane=1:2, volume ratio) to obtain a white-brown solid (1.25 g, yield: 40%). Mass Spectrum MALDI-TOF (m/z) [M ⁺ ]: The measured value is 623.55, and the theoretical value is 622.32.

Synthesis of _P8 : _P8 was prepared by Suzuki coupling. In a 100mL round bottom flask, M ₁ (5mmol, 1.78g), M ₁₇ (5mmol, 3.11g), tetrakistriphenylphosphine palladium (0.1mmol, 115mg) were dissolved in 40mL of toluene and 20mL of aqueous potassium carbonate (2.0mol L ^-1 ), stirred and refluxed at 90°C for 24 hours under nitrogen protection. After the reaction, extract with dichloromethane, concentrate the extract by rotary evaporation, and separate by column chromatography (petroleum ether:dichloromethane=1:2, volume ratio) to obtain a light green solid (3.23g, yield: 70%). The product is further raised by sublimation. Mass spectrum MALDI-TOF (m/z) [M ⁺ ]: The measured value is 925.36, and the theoretical value is 924.33. Elemental analysis (%) C48H29N3: theoretical value C 89.59, H 4.36, N 6.06; test value C 89.57, H 4.35, N 6.08

Example 9

A non-doped organic electroluminescent device, which uses small organic blue light molecules with a molecular structure of P1 as the light-emitting layer material, and the structure of the organic electroluminescent device is as follows:

ITO/HATCN(6nm)/TAPC(25nm)/TCTA(15nm)/EML(20nm)/TPBI(40nm)/LiF(1nm)/Al(120nm). Among them, EML is the non-doped light-emitting layer with P1 as the light-emitting material

The device preparation process is as follows: soak the ITO transparent conductive glass in the deionized water: ethanol mixture for two hours, then wipe it clean with a dust-free paper, then ultrasonically clean it with deionized water, and finally wash it with isopropanol-acetone-toluene in sequence. - Acetone - isopropanol repeated ultrasonic cleaning three times. Before preparing the device, dry the ITO glass substrate with nitrogen, irradiate it under ultraviolet ozone for half an hour, then place it in the evaporation chamber, vacuumize it to 5×10 ^-4 Pa, and evaporate it sequentially on the above-mentioned ITO glass substrate The material required for the device is obtained to obtain an organic electroluminescence device. The specific description is as follows: HATCN is a hole injection layer with a thickness of 6nm and an evaporation rate of 0.1A s ^-1 ; TAPC is a hole transport layer with a thickness of 25nm and an evaporation rate of 0.3A s ^-1 ; TCTA is a buffer layer with a thickness of 15nm and a deposition rate of 0.3A s ^-1 ; the luminescent layer with a thickness of 20nm and a deposition rate of 0.3A s ^-1 ; TPBI is an electron transport layer with a thickness of 40nm and a deposition rate of 0.4A s ^{- 1} ; LiF is the electron injection layer, the thickness is 1nm, and the evaporation rate is 0.1A s ^-1 ; Al is the cathode, the thickness is 120nm, and the evaporation rate is slightly slow at the beginning, which is 0.7A s ^-1 , with the thickness of the Al layer Increase, when the thickness of the Al layer reaches 20nm, the evaporation speed of the Al layer can be gradually increased to 2A s ^-1 .

In this embodiment, the current density-voltage-brightness curve, current efficiency-brightness curve and electroluminescent spectrum under different voltages of the non-doped organic electroluminescent device with _P1 light-emitting layer material are shown in Fig. 5, Fig. 6 and Fig. 6 respectively. Figure 7 shows. The photoelectric properties of the obtained devices are shown in Table 1.

Table 1: Performance results of non-doped blue OLEDs device in Example 9

The structural formula of the material used in the organic electroluminescent device of the present embodiment is as follows:

The above-mentioned embodiment is a preferred embodiment of the present invention, but the embodiment of the present invention is not limited by the above-mentioned embodiment, and any other changes, modifications, substitutions, combinations, Simplifications should be equivalent replacement methods, and all are included in the protection scope of the present invention.

Claims (4)

1. A small organic blue light molecule based on triplet-triplet annihilation mechanism, whose structural formula is shown as P1n or P2n: Wherein Ar represents the aromatic group shown in the following structural formula, 2. A small organic blue light molecule based on a triplet-triplet annihilation mechanism according to claim 1, whose structural formula is as shown in one of P ₁ -P ₈ : 3. The application of a kind of organic blue light molecule based on triplet-triplet annihilation mechanism described in claim 1 or 2 in the preparation of non-doped blue light OLEDs devices. 4. The application of a kind of organic blue light small molecules based on triplet-triplet annihilation mechanism in the preparation of non-doped blue OLEDs device as claimed in claim 3, the OLEDs device consists of glass substrate, ITO anode, hole transport layer , a light-emitting layer, an electron transport layer and a cathode; it is characterized in that: the light-emitting layer contains at least one organic blue-light small molecule based on phenanthroimidazole-anthracene derivatives as described in claim 1 or 2.