阅读说明：本技术 高效率电子阻挡材料及使用该种材料的有机电致发光器件 (High-efficiency electron blocking material and organic electroluminescent device using same ) 是由 钱超 许军 于 2019-07-19 设计创作，主要内容包括：本发明公开了一种高效率电子阻挡材料及使用该种材料的有机电致发光器件,结构式如式I所示：<Image he="552" wi="700" file="DDA0002136117150000011.GIF" imgContent="drawing" imgFormat="GIF" orientation="portrait" inline="no"></Image>通过使用本发明高效率电子阻挡材料,将载流子和激子限制在发光层中,可以有效消除电子逸出和激子扩散,从而提高了外量子效率,进一步改善器件的工作寿命,采用本发明高效率电子阻挡层材料制备的有机电致发光器件驱动电压大大降低,大幅度减少了电能的消耗、显著提高了发光效率。另外通过降低驱动电压,有机电致发光器件的寿命有显著提高。(The invention discloses a high-efficiency electron blocking material and an organic electroluminescent device using the same, and the structural formula is shown as formula I:)

1. A high-efficiency electron blocking material is characterized in that the structural formula is as follows:

wherein L is₁And L₂Each independently represents a substituted or unsubstituted aromatic group of C6-C14, a substituted or unsubstituted heteroaromatic group of C5-C18;

p is 0 or 1;

R₁independently represent an aromatic group of C6-C12 or a heteroaromatic group of C5-C18;

R₂、R₃each independently represents hydrogen or phenyl;

R₄independently represent a substituted or unsubstituted aromatic group of C6-C14 and a substituted or unsubstituted heteroaromatic group of C5-C18.

2. A high efficiency electron blocking material as claimed in claim 1 wherein L is₁、L₂Each independently selected from phenyl, biphenyl, fluorenyl, oxyfluorenyl, thiofluorenyl, dimethylfluorenyl, anthracenyl or N-phenylcarbazolyl.

3. The high efficiency electron blocking material of claim 1, wherein R1 is selected from one of phenyl, biphenyl, dimethylfluorenyl, benzophenanthrenyl, N-phenylcarbazolyl, or carbazolyl.

4. The high efficiency electron blocking material of claim 1, wherein R4 is selected from one of phenyl, anthracyl, naphthyl, dimethylfluorenyl, phenanthryl, benzophenanthryl, N-phenylcarbazolyl, or carbazolyl.

5. The high efficiency electron blocking material of any one of claims 1 to 4, wherein the high efficiency electron blocking material is any one of the compounds of the following structural formula:

6. a method of preparing a high efficiency electron blocking material as claimed in any one of claims 1 to 4, comprising the steps of:

(1)

under the protection of gas, adding a structural general formula ofCompound A of the general formulaAfter the addition of the compound B, sodium tert-butoxide, palladium dibenzylideneacetone, tri-tert-butylphosphine and toluene is finished, heating to reflux reaction for 10-20h, stopping the reaction, cooling the reaction solution to room temperature, adding water, stirring at room temperature for 10-30min, filtering, drying a filter cake, separating the filtrate to obtain an organic phase, drying the organic phase, purifying to obtain a filtrate, concentrating the filtrate, mixing the filtrate with the filter cake, completely dissolving the filtrate with a proper amount of dichloromethane, adding silica gel powder after the dissolution is finished, mixing the mixture with a sample, and purifying by column chromatography to obtain an intermediate C;

(2)

under the protection of inert gas, adding a reaction vessel with a structural general formulaThe intermediate C has a structural general formulaAfter the addition of the compound D, sodium tert-butoxide, palladium dibenzylideneacetone, tri-tert-butylphosphine and toluene is finished, heating to reflux reaction for 10-20h, stopping the reaction, cooling the reaction solution to room temperature, adding water, stirring at room temperature for 10-30min, filtering, drying a filter cake, completely dissolving the filter cake with a proper amount of dichloromethane, adding silica gel powder after the dissolution is finished, stirring the sample, and purifying the sample by column chromatography to obtain an intermediate E;

(3)

under the protection of inert gas, adding a reaction vessel with a structural general formulaIntermediate E of (A) has a structural general formulaAfter the charging is finished, heating to reflux reaction for 10-20h, stopping the reaction, cooling the reaction liquid to room temperature, adding water, stirring at room temperature for 10-30min, filtering, drying a filter cake, completely dissolving the filter cake by using a proper amount of dichloromethane, adding silica gel powder after the dissolution is finished, stirring, and performing column chromatography purification and recrystallization to obtain the high-efficiency electronic blocking material.

7. Use of the high efficiency electron blocking material of any of claims 1-4 in an organic electroluminescent device.

8. An organic electroluminescent device comprising an anode, a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, an electron injection layer and a cathode arranged in this order, wherein an electron blocking layer is further arranged between the hole transport layer and the light emitting layer, and the electron blocking layer comprises at least one high efficiency electron blocking material as claimed in claims 1 to 4.

9. The organic electroluminescent device according to claim 8, wherein the light-emitting layer and/or the hole transport layer contains at least one high efficiency electron blocking material as claimed in claims 1 to 4.

10. An electronic illumination device characterized by comprising the organic electroluminescent device according to claim 8.

Technical Field

The invention relates to the technical field of organic electroluminescent materials, in particular to a high-efficiency electronic barrier material and an organic electroluminescent device using the same.

Background

The Organic Light-Emitting Devices (OLEDs) have a series of advantages such as self-luminescence, low-voltage dc driving, full curing, wide viewing angle, rich colors, etc., and compared with the liquid crystal display, the OLEDs do not need a backlight source, have a large viewing angle, low power consumption, a response speed 1000 times that of the liquid crystal display, a manufacturing cost lower than that of the liquid crystal display with the same resolution, and are ultra-thin, and can be manufactured on a flexible panel. Therefore, the organic electroluminescent diode attracts attention due to the potential application thereof in the new generation display and lighting technology, has a very wide application prospect, and is widely applied to the fields of mobile phones, tablet computers, televisions, lighting and the like.

The organic electroluminescent device is like a sandwich structure and comprises a cathode layer, an anode layer and an organic thin film layer positioned between the two layers. The organic thin film layer can comprise one or more functional layers of an electron injection layer, an electron transport layer, a hole blocking layer, a hole transport layer, a hole injection layer and an organic light-emitting layer. The research on the improvement of the performance of the organic electroluminescent device includes: the driving voltage of the device is reduced, the luminous efficiency of the device is improved, the service life of the device is prolonged, and the like.

Although the research on organic electroluminescence is rapidly progressing, there are still many problems to be solved urgently, and for an organic electroluminescent device, the luminous quantum efficiency of the device is a comprehensive reflection of various factors and is an important index for measuring the quality of the device. Generally, one of the main reasons for the low EQE of the device is caused by the imbalance between the charge injection and the charge transport of the light emitting material. Meanwhile, the imbalance also seriously affects the stability of the device, so that the device cannot meet the requirement of practicability. If equilibrium is not reached, current will flow inefficiently (no light emission). For example, if we cannot localize the recombination of carriers to some desired region within the device (typically the light emitting layer) but rather at the interface of the readily quenchable electrode and the working substance, the quantum efficiency of the device's emission will be greatly reduced. To overcome this difficulty, it is necessary to have a reasonable arrangement of potential barriers at the interface layers of the two electrodes and the working substance, which barriers are generally not too high in order to ensure that the injection of carriers can be performed at a lower driving voltage, since the potential barriers are generated due to the difference between the work function of the positive (or negative) electrode and the ionization potential (or electron affinity) of the working substance. For this reason, the height of the potential barrier must be predicted to some extent. Unfortunately, few reports have been made in the literature on the Ionization Potential (IP) or Electron Affinity (EA) of these working substances, and the values obtained by theoretical calculation are generally relatively dispersed, which makes it difficult to select a suitable new electron transporting/hole blocking material to match the electrode material. Since many organic materials can effectively transport holes, in order to improve the light emitting efficiency of the device, in many cases, an additional electron transport/hole blocking layer is added on the cathode side to block hole transport, and the carrier recombination is limited in the light emitting layer region.

In order to realize the continuous improvement of the performance of the organic electroluminescent device, not only the innovation of the structure and the manufacturing process of the organic electroluminescent device is required, but also the continuous research and innovation of the organic electro-photoelectric functional material are required, so that the organic electroluminescent functional material with higher performance is created.

Disclosure of Invention

The purpose of the invention is as follows: in view of the above technical problems, the present invention provides a high efficiency electron blocking material and an organic electroluminescent device using the same.

A high-efficiency electron blocking material has a structural formula as follows:

wherein L is₁And L₂Each independently represents a substituted or unsubstituted aromatic group of C6-C14, a substituted or unsubstituted heteroaromatic group of C5-C18;

p is 0 or 1;

R₁independently represent an aromatic group of C6-C12 or C5-A heteroaromatic group of C18;

R₂、R₃each independently represents hydrogen or phenyl;

R₄independently represent a substituted or unsubstituted aromatic group of C6-C14 and a substituted or unsubstituted heteroaromatic group of C5-C18.

Preferably, L₁、L₂Each independently selected from phenyl, biphenyl, fluorenyl, oxyfluorenyl, thiofluorenyl, dimethylfluorenyl, anthracenyl or N-phenylcarbazolyl.

Preferably, R1 is selected from one of phenyl, biphenyl, dimethylfluorenyl, benzophenanthrenyl, N-phenylcarbazolyl, or carbazolyl.

Preferably, R4 is selected from one of phenyl, anthracenyl, naphthyl, dimethylfluorenyl, phenanthrenyl, benzophenanthrenyl, N-phenylcarbazolyl, or carbazolyl.

Preferably, the high efficiency electron blocking material is any one of the compounds of the following structural formula:

the preparation method of the electron blocking material comprises the following steps:

(1)

under the protection of inert gas, adding a reaction vessel with a structural general formulaCompound A of the general formulaAfter the addition of the compound B, sodium tert-butoxide, palladium dibenzylideneacetone, tri-tert-butylphosphine and toluene is finished, heating to reflux reaction for 10-20h, stopping the reaction, cooling the reaction solution to room temperature, adding water, stirring at room temperature for 10-30min, filtering, drying a filter cake, separating the filtrate to obtain an organic phase, drying the organic phase, purifying to obtain a filtrate, concentrating the filtrate, mixing the filtrate with the filter cake, completely dissolving the filtrate with a proper amount of dichloromethane, adding silica gel powder after the dissolution is finished, mixing the mixture with a sample, and purifying by column chromatography to obtain an intermediate C;

(2)

under the protection of inert gas, adding a reaction vessel with a structural general formulaThe intermediate C has a structural general formulaAfter the charging of the compound D, sodium tert-butoxide, palladium dibenzylideneacetone, tri-tert-butylphosphine and toluene, heating to reflux reaction for 10-20h, stopping the reaction, cooling the reaction solution to room temperature, adding water, stirring at room temperature for 10-30min, filtering, drying the filter cake, and then adding the filter cakeDissolving the intermediate E completely by using a proper amount of dichloromethane, adding silica gel powder after the dissolution is finished, mixing the sample, and purifying the mixture by column chromatography to obtain an intermediate E;

(3)

under the protection of inert gas, adding a reaction vessel with a structural general formulaIntermediate E of (A) has a structural general formulaAfter the charging is finished, heating to reflux reaction for 10-20h, stopping the reaction, cooling the reaction liquid to room temperature, adding water, stirring at room temperature for 10-30min, filtering, drying a filter cake, completely dissolving the filter cake by using a proper amount of dichloromethane, adding silica gel powder after the dissolution is finished, stirring, and performing column chromatography purification and recrystallization to obtain the high-efficiency electronic blocking material.

The high-efficiency electron blocking material is applied to an organic electroluminescent device.

An organic electroluminescent device comprises an anode, a hole injection layer, a hole transport layer, a luminescent layer, an electron transport layer, an electron injection layer and a cathode which are sequentially arranged, wherein an electron blocking layer is further arranged between the hole transport layer and the luminescent layer, and the electron blocking layer contains at least one high-efficiency electron blocking material.

Preferably, the light-emitting layer and/or the hole transport layer contain at least one of the above-described high efficiency electron blocking materials.

An electronic lighting device comprises the organic electroluminescent device.

The room temperature of the invention is 25 +/-5 ℃.

The invention has the beneficial effects that:

the high-efficiency electron blocking material has a lower LUMO energy level, and the lower LUMO has the following two advantages: 1. the organic electroluminescent material can effectively prevent electrons from entering the hole transport layer through the luminescent layer and being combined with holes to generate excitons, thereby improving the service efficiency of the holes and the electrons; 2. the carrier and the exciton can be limited in the luminescent layer, and the escape of electrons and diffusion of excitons can be effectively eliminated, so that the external quantum efficiency is improved, and the luminescent efficiency and the service life of the device are further improved.

The R4 groups in the invention are plane rigid groups with larger conjugation effect, the introduction of the groups can increase the stability of material molecules and the carrier moving rate, and the service life and the luminous efficiency of a luminescent device using the materials are greatly increased. The most excellent groups of the molecular stability and the carrier efficiency of the material are triphenylene group and phenanthrene group, and the material has more excellent luminous efficiency and service life through device verification.

The device verifies that the organic electroluminescent device prepared by adopting the high-efficiency electronic barrier layer material has obviously improved driving voltage, luminous efficiency and service life, wherein R4 is triphenylene and phenanthrene base, and the performance is more excellent.

Detailed Description