CN102786508A - Spiro-fluorene-9,9-xanthene bipolar luminescent material, its preparation method and its application method - Google Patents

Abstract

The spirofluorene xanthene bipolar host material can effectively inhibit the intermolecular interaction due to its vertical spiro ring structure, thereby inhibiting the intermolecular interaction and dimer luminescence, and has good thermal stability and stable amorphous form . The present invention is a main material of spiro-9,9-oxanthene fluorene, and the specific design structure is as follows:

In particular, it relates to a preparation method and an application in an organic light emitting diode device. The material has: (1) high thermal stability and stable amorphous form; (2) has a three-dimensional steric hindrance effect, which can effectively inhibit dimer light emission; (3) the preparation method and synthesis conditions are simple and feasible, High luminous efficiency. Preliminary studies on its device structure and its properties show that the material can be used in red and green light organic electroluminescent devices. The research results show that these compounds have great application value and broad application prospects as host materials in organic light-emitting diodes.

Description

Spiro-9,9-oxanthene fluorene bipolar luminescent material and its preparation and application method

technical field

The present invention specifically relates to a preparation method based on functionalizing the active site of spiro-9,9-fluorenoxanthene, and relates to the steps and raw materials used in the preparation process of these materials.

Background technique

Due to its huge potential application value in flat panel display, organic light emitting diodes have made great progress in the past two decades. In 1987, Deng Qingyun and others used organic small molecule semiconductors to prepare low-voltage high-brightness light-emitting diodes for the first time, and then Burroughes et al. used conjugated polymers to prepare yellow-green electroluminescent devices for the first time in 1990. Especially since the first commercialization of organic light-emitting diodes in 1997, organic light-emitting diodes have been recognized as the next-generation flat-panel display and lighting technology. However, organic electroluminescent diodes have been limited to an internal quantum efficiency of 25%. In order to break through this limitation, phosphorescent organic light-emitting diodes came into being. In order to prevent the concentration quenching and triplet annihilation of phosphorescent guest materials in solid state due to high concentration, they are usually doped into host materials. For this reason, it is particularly important to design and synthesize appropriate host materials. Generally, host materials with excellent performance need to meet the following conditions: first, high triplet energy level to prevent energy inversion between host and guest materials; second, good film-forming properties and high thermal stability to improve The stability of the device; thirdly, the appropriate HOMO/LUMO energy level enables the effective transport of charges between the light-emitting layer and its adjacent layers. Due to the two vertical non-conjugated units, the spiro compound has a rigid structure with three-dimensional large-volume steric hindrance, which can effectively inhibit the interaction between one π molecular unit, making it have good film-forming properties and High thermal stability; and because of its non-conjugated connection of two vertical units, it can prevent the reduction of its triplet energy level and many other advantages, so it is often used in host materials. In order to optimize the device structure so that excitons can emit efficiently in the light-emitting layer to improve device performance, bipolar molecules have been widely used in host materials in recent years. Bipolar molecules have the ability to transport both holes and electrons, which can effectively balance the carriers and expand the exciton recombination area, so that the excitons can effectively recombine and emit light in the guest material, improving the luminous efficiency of the device.

Rigid planar fluorene has high thermal stability and high triplet energy level (2.95 eV), and is usually used as a hole transport group; isoquinoline has a large conjugated system electron-withdrawing group and has a good ability to transport electrons . To this end, this paper designed and synthesized a series of bipolar spiro compounds with spiro-9,9-oxanthene fluorene as the core and introduced multiple pyridine aryl units, which have good film-forming properties and High thermal stability and high triplet energy level and good hole transport performance. In addition, by introducing different numbers of electron-withdrawing quinoline groups on the periphery of spiroxanthene fluorene, the electron transport ability and orbital energy level of the compound can be adjusted. The hole-transporting ability and the electron-transporting ability of the bipolar spirocyclic compound are made to balance each other, so as to expand the efficient recombination of excitons in the light-emitting layer and improve the performance of the device.

In a word, the present invention follows the frontier dynamics of organic electroluminescent diode devices on the premise of a comprehensive understanding of current organic electroluminescent materials, and revolves around the synthesis of organic electroluminescent host materials, the preparation of EL devices and their related structures and properties interrelationships unfold. Guided by molecular design, design and synthesize stable and effective host materials to prepare stable and efficient phosphorescent devices.

Contents of the invention

Technical problem: The purpose of the present invention is to provide a spiro-9,9-oxanthrene bipolar luminescent material and its preparation and application method. The design and synthesis is based on a spiro-9,9-oxanthrene bipolar Polar host luminescent materials are used to prepare stable and effective bipolar host materials, which are widely used in electroluminescence and storage devices.

Technical solution: The present invention is a spiro-9,9-oxanthrene-based bipolar luminescent material, which functionalizes the active site of spiro-9,9-oxanthrene, so that it has both Transport holes and electrons, so as to achieve device structure simplification and high-efficiency light emission, which has the following structure:

Formula I

R ₁ , R ₂ , R ₃ , R ₄ , R ₅ and R ₆ are pyridine-containing aromatic ring structures or hydrogen atoms, specifically as follows:

。

.

The compounds represented by the general formula I all contain spiro-9,9-oxanthrene, and all introduced functional functional groups R ₁ - R ₆ are connected to the active sites of spiro-9,9-oxanthrene .

The preparation method of the spiro-9,9-oxanthene fluorene bipolar luminescent material of the present invention is as follows:

a. Take 9-fluorenone, phenol and methanesulfonic acid and heat them to 120-160°C under the condition of avoiding light and nitrogen protection. After the reaction is complete, then cool to room temperature, neutralize with sodium hydroxide aqueous solution until alkaline, and filter with suction Obtain high purity to obtain the crude product spiro-9,9-oxanthrene;

b. Take spiro-9,9-xanthene fluorene and dichloromethane in turn, stir and dissolve in an ice-water bath and nitrogen protection, then slowly add acetic anhydride into the reaction flask through a constant pressure dropping funnel, and react 2 After -36 hours; the reaction mixture was slowly added to the ice-water mixture to quench, extracted with dichloromethane, the combined organic phase was dried with anhydrous magnesium sulfate, concentrated by suction filtration under pressure, and the mixture of ethyl acetate and petroleum ether was used as Eluent, column chromatography to obtain high-purity spiro-9,9-oxanthrene fluorene monoacetylated products and diacetylated products;

c. Take spiro-9,9-xanthene fluorene and dichloromethane in turn, stirring and dissolving under the protection of nitrogen in an ice-water bath, then slowly add acetic acid chlorine into the reaction flask through a constant pressure dropping funnel, and react 2 After -36 hours, the reaction mixture was slowly added to an ice-water mixture to quench, extracted with dichloromethane, and the combined organic phases were dried over anhydrous magnesium sulfate, concentrated by suction filtration under pressure, and prepared as a mixture of ethyl acetate and petroleum ether. Eluent, high-purity spiro-9,9-oxanthene fluorene diacetylated product obtained by column chromatography;

d. Take acetyl chloride and dichloromethane in turn, stir and dissolve them in an ice-water bath under the protection of nitrogen, then dissolve spiro-9,9-oxanthene fluorene in dichloromethane and slowly drop them into the reaction through a constant pressure dropping funnel. bottle, after 2-36 hours of reaction, the reaction mixture was slowly added to an ice-water mixture to quench, extracted with dichloromethane, the combined organic phases were dried over anhydrous magnesium sulfate, concentrated by suction filtration under pressure, and extracted with ethyl acetate and A mixture of petroleum ether is used as an eluent, and high-purity spiro-9,9-oxanthene fluorene triacetylation product is obtained by column chromatography;

e. Add 2-acetyl-spiro-9,9'xanthene fluorene and o-aminoaryl formaldehyde into the reactor sequentially under nitrogen protection, inject saturated potassium hydroxide solution and ethanol and heat to reflux overnight, wash with water, Extracted with dichloromethane, combined organic phases, dried with anhydrous magnesium sulfate, concentrated by rotary evaporator, using petroleum ether and dichloromethane as eluent, column chromatography to obtain high-purity compound I;

f. Under nitrogen protection, take 2,2'-diacetyl-spiro-9,9'-xanthene fluorene and o-aminoaryl formaldehyde into the reaction flask in turn, inject saturated potassium hydroxide solution and ethanol and heat Reflux overnight, wash with water, extract with dichloromethane, combine organic phases, dry over anhydrous magnesium sulfate, concentrate by rotary evaporator, use petroleum ether and dichloromethane as eluents, and obtain high-purity compound II by column chromatography;

g. Under the protection of nitrogen, take 2,2'-triacetyl-spiro-9,9'-xanthene fluorene and o-aminoaryl formaldehyde into the reaction flask, inject saturated potassium hydroxide solution and ethanol and heat Reflux overnight, wash with water, extract with dichloromethane, combine organic phases, dry over anhydrous magnesium sulfate, concentrate by rotary evaporator, use petroleum ether and dichloromethane as eluents, and obtain high-purity compound III by column chromatography;

Its general feature structure is as follows:

The material is applied to organic electroluminescent devices. The organic electroluminescence device is a light-emitting diode, and the structure of the light-emitting diode device is a transparent anode/light-emitting layer/electron injection layer/cathode, wherein the light-emitting layer is a host-guest system, and spiro-9,9-oxanthene fluorenes The bipolar luminescent material is used as the host material of the luminescent layer.

Beneficial effects: the complex spiroaryl fluorene material structure is characterized by elemental analysis, infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR), chromatography-mass chromatography (GCMS), and gel chromatography (GPC), and thermal gravimetric analysis and differential thermal analysis The thermal stability of the materials was tested, and their optical and electrochemical properties were characterized by ultraviolet fluorescence spectroscopy and cyclic voltammetry. Such materials show good thermal stability in thermogravimetric analysis and differential thermal analysis, and UV, fluorescence, and electrochemical analysis show that they have good optoelectronic properties. Therefore, such materials can be widely used in organic light-emitting diodes, organic lasers, organic electrical storage devices, organic field effect transistors, and the like.

On this basis, a preliminary electroluminescent device was designed to evaluate the luminescent properties of spiro-9,9-oxanthrene bipolar host materials. The structure of the device is transparent anode/hole injection layer/buffer layer/hole injection layer/hole transport layer/light emitting layer/electron transport layer/cathode, in which spiro-9,9-oxanthene fluorene bipolar The main material is prepared by vacuum evaporation, and the cathode is prepared by vacuum coating technology. The experimental results show that these spiro-9,9-oxanthene fluorene bipolar host materials show high-efficiency phosphorescence emission properties, and the guest materials such as Ir(ppy) ₃ , Ir(MDQ) ₂ (acac) can pass through the evaporation Technology realizes red and green photoluminescence technology.

The main advantages of the present invention are:

1. The synthesis steps are simple and efficient, and the reaction conditions are simple;

2. It has high thermal stability and stable amorphous form, which is conducive to the preparation of stable electroluminescent devices.

3. Has an appropriate triplet energy level

4. With suitable HOMO and LUMO energy levels

5. Has three-dimensional space hindrance effect

Description of drawings:

Figure 1. The MODITOF pattern and ¹ HNMR pattern of 2'-isoquinolinyl-spiro-9, 9'-xanthene fluorene,

Figure 2. The MODITOF pattern and ¹ HNMR pattern of 2, 2'-diisoquinolinyl-spiro-9, 9'-xanthene fluorene,

Figure 3. MODITOF pattern and ¹ HNMR pattern of 2, 2', 2''-triisoquinolinyl-spiro-9, 9'-xanthene fluorene,

Figure 4. With 2'-isoquinolinyl-spiro-9, 9'-xanthrene, 2, 2'-diisoquinolinyl-spiro-9, 9'-xanthrene, 2, 2 ', 2''-triisoquinolinyl-spiro-9, 9'-xanthene fluorene are the electroluminescence spectra of the host material of the device, respectively,

Figure 5. Luminance-Voltage-Current density curves of green light devices G1-G3,

Figure 6. External quantum efficiency (E.Q.E)-current density (Current density) curves of green light devices G1-G3.

Figure 7. Schematic diagram of the structure of a light-emitting diode device.

Detailed ways

The technical solutions of the present invention will be further described below in conjunction with examples, but these examples are not intended to limit the implementation of the present invention. The present invention has many different embodiments, and is not limited to the content described in this specification. The solutions completed by those skilled in the art should fall within the scope of the present invention without departing from the spirit of the present invention.

Example 1: spiro-9,9-xanthene fluorene

Take 9-fluorenone (3.474 g, 19.3 mmol), phenol (18 g, 191.4 mmol) and methanesulfonic acid (5.0 mL, 77.2 mmol) and heat to reflux at 150°C for 24 hours under the condition of dark and nitrogen protection. It was then cooled to room temperature, neutralized to alkaline with aqueous sodium hydroxide solution, and filtered with suction to obtain a crude product of spiro-9,9-oxanthene fluorene with high purity (yield, 85%).

Example 2: 2'-Acetyl-spiro-9,9-xanthene fluorene

Spiro-9,9-xanthene fluorene (3.3200 g, 10 mmol) and 50 mL of dichloromethane were stirred and dissolved in an ice-water bath under the protection of nitrogen for 20 minutes, and then acetic anhydride (0.94 mL, 10 mmol) was The constant pressure dropping funnel was slowly added dropwise to the reaction bottle, and reacted for 24 hours. The reaction mixture was slowly added to an ice-water mixture to quench, extracted with dichloromethane, the combined organic phases were dried over anhydrous magnesium sulfate, concentrated by suction filtration under pressure. Using a mixture of ethyl acetate and petroleum ether as the eluent, a white product was obtained by column chromatography (yield, 47%).

Example 3: Synthesis of 2'-isoquinolinyl-spiro-9,9'-oxanthrene:

Under the protection of nitrogen, 2-acetyl-9,9'spiroxanthene fluorene (1.1120 g, 3 mmol) and anthranilaldehyde (1.8200 g, 15.0 mmol) were successively added to the reaction flask, and saturated potassium hydroxide was injected Solution 5mL and ethanol 25mL were refluxed overnight at 90°C, washed with water, extracted with dichloromethane, combined organic phases, dried over anhydrous magnesium sulfate, concentrated by rotary evaporator, using petroleum ether and dichloromethane as eluents, column The product was obtained by chromatography (yield, 44%). GC-MS (EI) m/z 459 [M ⁺ ];1H NMR (400 MHz, CDCl ₃ ): δ (ppm) 8.13 (dd, J = 8.6, 1H), 8.0 (m, 2H), 7.84 (d , J = 7.63, 2H), 7.71 (d, J = 8.04, 1H), 7.64 (t, J = 6.98, 1H), 7.41 (m, 5H), 7.28 (s, 1H), 7.22 (m,5H) , 7.08 (s, J = 2.16, 1H) , 6.80 (s, J = 8.12, 1H) , 6.44 (s, J = 7.81, 1H).

Example 4: Synthesis of 2,2'-diacetyl-spiro-9,9-oxanthrene:

9,9 spiro-xanthene fluorene (3.32 g, 10 mmol) and 50 mL of dichloromethane were taken successively, stirred and dissolved in an ice-water bath under nitrogen protection for 20 minutes, and then acetic anhydride (3.76 mL, 40 mmol) was constant Slowly add dropwise into the reaction flask from the dropping funnel, and react for 24 hours. The reaction mixture was slowly added to an ice-water mixture to quench, extracted with dichloromethane, the combined organic phases were dried over anhydrous magnesium sulfate, concentrated by suction filtration under pressure. Using a mixture of ethyl acetate and petroleum ether as the eluent, a white product was obtained by column chromatography (yield, 36%). GC-MS (EI) m/z 416 [M ⁺ ];1H NMR (400 MHz, CDCl ₃ ): δ (ppm) 8.02 (d, J = 7.92, 1H), 7.89 (m, 2H), 7.82 (m , 1H), 7.77 (s, 1H), 7.44 (t, J = 7.55, 1H), 8.11 (t, J = 7.30, 2H), 7.26 (m, 1H), 7.22 (m, 1H), 7.16 (d , J = 7.66, 1H), 7.00 (s, 1H), 6.80 (m, 1H) , 6.35 (d, J = 7.99, 1H) , 2.52 (s, 3H) , 2.31 (s, 3H).

Example 5: Synthesis of 2,2'-diisoquinolinyl-9,9'-spiroxanthene fluorene:

Under the protection of nitrogen, 2,2'-diacetyl-9,9'-spiroxanthene fluorene (1.2500 g, 3.0 mmol) and anthranilaldehyde (1.8200 g, 15.0 mmol) were successively added to the reaction flask, Inject 5 mL of saturated potassium hydroxide solution and 25 mL of ethanol and reflux overnight at 90°C, wash with water, extract with dichloromethane, combine the organic phases, dry over anhydrous magnesium sulfate, concentrate with a rotary evaporator, and use petroleum ether and dichloromethane as eluent, and the product was obtained by column chromatography (yield, 28%). MODITOF(EI) m/z 586 [M ⁺ ]; ¹ H NMR (400 MHz, CDCl ₃ ): δ (ppm) 8.37 (d, J = 7.99, 1H), 8.16 (m, 1H), 8.11 (m, 2H), 7.99 (m, 4H), 7.90 (d, J = 7.62, 1H), 7.76 (d, J = 8.64, 2H), 7.68 (m, 2H), 7.62 (m, 1H), 7.43 (m, 5H) , 7.30 (s, J = 9.35, 1H) , 7.25 (m, 2H) , 7.21 (m, 1H) , 7.68 (m, 1H), 7.14 (d, J = 2.16, 1H) , 6.50 (t, J = 7.85, 1H).

Example 6: Synthesis of 2,2',2'-triacetyl-9,9 spiro-xanthene fluorene

Acetyl chloride (2.12 mL, 30 mmol) and 50 mL of dichloromethane were taken successively, stirred and dissolved in an ice-water bath under nitrogen protection for 20 minutes, and then 9,9 spiro-xanthene fluorene (3.32 g, 10 mmol) was dissolved with di Dissolved methyl chloride was slowly added dropwise to the reaction flask through a constant pressure dropping funnel, and reacted for 24 hours. The reaction mixture was slowly added to an ice-water mixture to quench, extracted with dichloromethane, the combined organic phases were dried over anhydrous magnesium sulfate, concentrated by suction filtration under pressure. A white product was obtained by column chromatography using a mixture of ethyl acetate and petroleum ether as the eluent. GC-MS (EI) m/z 458 [M ⁺ ]; ¹ H NMR (400 MHz, CDCl ₃ ): δ (ppm) 8.03 (d, J = 7.93, 1H), 7.92 (m, 2H), 7.83 ( dd, J = 2.14, 2H), 7.68 (s, 1H), 7.46 (t, J = 7.53, 1H), 7.32 (t, J = 7.38, 3H), 7.12 (d, J = 7.60, 1H), 6.98 (m, J = 2.07, 2H), 2.52 (s, 3H) , 2.31 (s, 6H).

Example 7: Synthesis of 2, 2', 2''-triisoquinolinyl-9, 9'-spiroxanthene fluorene

Under the protection of nitrogen, 2,2'-triacetyl-9,9'-spiroxanthene fluorene (1.3800 g, 3.0 mmol) and o-aminobenzaldehyde (1.8200 g, 15.0 mmol) were added to the reaction flask successively, Inject 5 mL of saturated potassium hydroxide solution and 25 mL of ethanol and reflux overnight at 90°C, wash with water, extract with dichloromethane, combine the organic phases, dry over anhydrous magnesium sulfate, concentrate with a rotary evaporator, and use petroleum ether and dichloromethane as Eluent, the product was obtained by column chromatography (yield, 40%). MODI-TOF (EI) m/z 713 [M ⁺ ];1H NMR (400 MHz, CDCl ₃ ): δ (ppm) 8.41 (d, J = 9.46, 1H), 8.18 (d, J = 8.55, 2H) , 8.08 (dd, J = 8.28, 3H), 7.99 (m, 5H), 7.94 (d, J = 7.73, 1H), 7.76 (t, J = 9.22, 2H), 7.70 (d, J = 7.66, 2H ), 7.64 (m, 3H), 7.43 (m, 8H), 7.30 (s, 2H), 7.15 (m, 2H).

Claims (5)

1. A spiro-9,9-oxanthrene-based bipolar luminescent material, characterized in that the material is functionalized with the active site of spiro-9,9-oxanthrene, so that it also has a transmission Holes and electrons, so as to achieve device structure simplification and high-efficiency light emission, which has the following structure:

Formula I R ₁ , R ₂ , R ₃ , R ₄ , R ₅ and R ₆ are pyridine-containing aromatic ring structures or hydrogen atoms, specifically as follows:

. 2. The spiro-9,9-oxanthene fluorene bipolar luminescent material according to claim 1, characterized in that the compounds represented by the general formula I all contain spiro-9,9-oxanthene Fluorene, all the introduced functional functional groups R ₁ - R ₆ are connected to the active site of spiro-9,9-oxanthene fluorene. 3. A preparation method of spiro-9,9-oxanthrene fluorene bipolar luminescent material as claimed in claim 1, characterized in that the preparation method is: a. Take 9-fluorenone, phenol and methanesulfonic acid and heat them to 120-160°C under the condition of avoiding light and nitrogen protection. After the reaction is complete, then cool to room temperature, neutralize with sodium hydroxide aqueous solution until alkaline, and filter with suction Obtain high purity to obtain the crude product spiro-9,9-oxanthene fluorene; b. Take spiro-9,9-xanthene fluorene and dichloromethane in turn, stir and dissolve in an ice-water bath and nitrogen protection, then slowly add acetic anhydride into the reaction flask through a constant pressure dropping funnel, and react 2 After -36 hours; the reaction mixture was slowly added to the ice-water mixture to quench, extracted with dichloromethane, the combined organic phase was dried with anhydrous magnesium sulfate, concentrated by suction filtration under pressure, and the mixture of ethyl acetate and petroleum ether was used as Eluent, column chromatography to obtain high-purity spiro-9,9-oxanthrene fluorene monoacetylated products and diacetylated products; c. Take spiro-9,9-xanthene fluorene and dichloromethane in turn, stirring and dissolving under the protection of nitrogen in an ice-water bath, then slowly add acetic acid chlorine into the reaction flask through a constant pressure dropping funnel, and react 2 After -36 hours, the reaction mixture was slowly added to an ice-water mixture to quench, extracted with dichloromethane, and the combined organic phases were dried over anhydrous magnesium sulfate, concentrated by suction filtration under pressure, and prepared as a mixture of ethyl acetate and petroleum ether. Eluent, high-purity spiro-9,9-oxanthene fluorene diacetylated product obtained by column chromatography; d. Take acetyl chloride and dichloromethane in turn, stir and dissolve them in an ice-water bath under the protection of nitrogen, then dissolve spiro-9,9-oxanthene fluorene in dichloromethane and slowly drop them into the reaction through a constant pressure dropping funnel. bottle, after 2-36 hours of reaction, the reaction mixture was slowly added to an ice-water mixture to quench, extracted with dichloromethane, the combined organic phases were dried over anhydrous magnesium sulfate, concentrated by suction filtration under pressure, and extracted with ethyl acetate and A mixture of petroleum ether is used as an eluent, and high-purity spiro-9,9-oxanthene fluorene triacetylation product is obtained by column chromatography; e. Add 2-acetyl-spiro-9,9'xanthene fluorene and o-aminoaryl formaldehyde into the reactor sequentially under nitrogen protection, inject saturated potassium hydroxide solution and ethanol and heat to reflux overnight, wash with water, Extracted with dichloromethane, combined organic phases, dried with anhydrous magnesium sulfate, concentrated by rotary evaporator, using petroleum ether and dichloromethane as eluent, column chromatography to obtain high-purity compound I; f. Under nitrogen protection, take 2,2'-diacetyl-spiro-9,9'-xanthene fluorene and o-aminoaryl formaldehyde into the reaction flask in turn, inject saturated potassium hydroxide solution and ethanol and heat Reflux overnight, wash with water, extract with dichloromethane, combine organic phases, dry over anhydrous magnesium sulfate, concentrate by rotary evaporator, use petroleum ether and dichloromethane as eluents, and obtain high-purity compound II by column chromatography; g. Under the protection of nitrogen, take 2,2'-triacetyl-spiro-9,9'-xanthene fluorene and o-aminoaryl formaldehyde into the reaction flask, inject saturated potassium hydroxide solution and ethanol and heat Reflux overnight, wash with water, extract with dichloromethane, combine organic phases, dry over anhydrous magnesium sulfate, concentrate by rotary evaporator, use petroleum ether and dichloromethane as eluents, and obtain high-purity compound III by column chromatography; Its general feature structure is as follows:

. 4. An application of the spiro-9,9-oxanthene fluorene bipolar luminescent material prepared according to claim 3, characterized in that the material is applied to an organic electroluminescent device. 5. The application of the spiro-9,9-oxanthene fluorene bipolar luminescent material as claimed in claim 4, wherein the organic electroluminescent device is a light emitting diode, and the structure of the light emitting diode device is transparent Anode/light-emitting layer/electron injection layer/cathode, wherein the light-emitting layer is a host-guest system, and the spiro-9,9-oxanthene fluorene bipolar light-emitting material is used as the host material of the light-emitting layer.

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