An organic electroluminescent device

Abstract

An organic electroluminescent device having a cathode and an anode and an organic light-emitting layer interposed between the two electrodes, and the light-emitting layer contains organic molecule I, organic molecule II and organic molecule III, wherein the organic molecule I is a host material, the organic molecule II is a sensitizing material, the organic molecule III is a light-emitting material, and the organic molecule I, the organic molecule II and the organic molecule III satisfy the condition represented by the following formula (A), Formula (A): E S1 (I) > E S1 (II) > E S1 (III) in the above formula (A), E S1 (I) represents the lowest excited singlet state energy level of the organic molecule I, E S1 (II) represents the lowest excited singlet state energy level of the organic molecule II, E S1 (III) represents the lowest excited singlet state energy level of the organic molecule III.

Description

Technical Field

[0001] This invention relates to the field of organic electroluminescence technology, and in particular to a highly efficient and stable blue light device. Background Technology

[0002] Organic light-emitting diodes (OLEDs) are devices that convert electrical energy into light energy using organic materials. OLEDs offer numerous advantages, including being ultra-lightweight, ultra-thin, having high pixel count, being foldable, having a wide viewing angle, high contrast, and being energy-efficient. An OLED structure consists of a cathode, an organic functional layer, and an anode. The organic functional layer includes a hole injection layer, a hole transport layer, an emissive layer, an electron transport layer, and an electron injection layer. The light emission process of an OLED achieves electroluminescence through the injection, transport, and recombination of charge carriers. Specifically, after an external electric field is applied to the OLED, holes are injected from the anode side through the hole injection layer, and electrons are injected from the cathode side through the electron injection layer. After transport through the hole transport layer and the electron transport layer, the two electrons meet in the emissive layer to form excitons. Under the influence of the electric field, the excitons diffuse and migrate in the emissive layer, relaxing from the excited state to the ground state on the luminescent material and emitting light through radiative transitions.

[0003] Currently, OLEDs have not completely replaced LCDs primarily because: First, the cost and difficulty of the vacuum evaporation process remain high, resulting in a relatively low yield rate for OLED production lines and persistently high OLED costs. However, with the continuous operation of existing production lines and the investment in new ones, the yield rate and output of OLED production lines are increasing year by year, and the cost of OLEDs will eventually decrease to a reasonable level. Second, there is still a lack of long-lifetime, high-efficiency blue light materials. Phosphorescent materials and thermally activated delayed fluorescence materials have high luminous efficiency but poor lifespan. Blue fluorescent materials have good stability but low efficiency. Therefore, finding efficient and stable blue light has always been a goal for those skilled in the art. Summary of the Invention

[0004] The purpose of this invention is to solve the problems of improving the efficiency, color purity, and lifespan of existing blue OLEDs. In view of this, this invention provides a novel organic electroluminescent device, which is realized through the following blue OLED. Specifically, this invention provides:

[0005] 1) An organic electroluminescent device comprising a cathode, an anode, and at least one organic layer containing a light-emitting layer sandwiched between the two electrodes. The light-emitting layer comprises organic molecule I, organic molecule II, and organic molecule III, wherein organic molecule I is the host material, organic molecule II is the sensitizing material, and organic molecule III is the light-emitting material, and organic molecule I, organic molecule II, and organic molecule III satisfy the condition represented by the following formula (A).

[0006] Formula (A): E S1 (Ⅰ)>E S1(Ⅱ)>E S1 (III)

[0007] In the above formula (A), E S1 (Ⅰ) represents the lowest excited singlet state energy level of organic molecule Ⅰ, E S1 (Ⅱ) represents the lowest excited singlet state energy level of the organic molecule Ⅱ, E S1 (Ⅲ) represents the lowest excited singlet energy level of the organic molecule Ⅲ;

[0008] Among them, the fluorescence radiation rate constant of organic molecule II is 5*10 8 s -1 ~5*10 10 s -1 Between these values, the full width at half maximum (FWHM) of organic molecule III is between 5 and 40 nm.

[0009] 2) According to the organic electroluminescent device described in 1), the organic molecule III emits blue light with a peak emission value between 440-490 nm.

[0010] 3) In the organic electroluminescent device according to 1) or 2), the mass content of organic molecule II in the light-emitting layer is between 0.5 wt% and 20 wt%, and the mass content of organic molecule III in the light-emitting layer is between 0.5 wt% and 20 wt%.

[0011] 4) The organic electroluminescent device according to any one of 1) to 3), wherein the organic molecule I of the light-emitting layer has a molecular structure as shown in general formulas H1 to H6:

[0012]

[0013] Ar 1 and Ar 2 Each can be independently represented as one of the following: aryl group with 6-50 cyclic carbon atoms (substituted or unsubstituted), heteroaryl group with 5-50 cyclic atoms (substituted or unsubstituted), arylamine group with 6-50 cyclic atoms (substituted or unsubstituted), or heteroarylamine group with 3-50 cyclic atoms (substituted or unsubstituted); Ar 1 and Ar 2 Same or different;

[0014] R(R 1 ~R 10Ra) represents one of the following: hydrogen atom, deuterium atom, tritium atom, halogen atom, cyano group, substituted or unsubstituted silyl group, substituted or unsubstituted alkyl group with 1 to 20 carbon atoms, substituted or unsubstituted cycloalkyl group with 3 to 20 carbon atoms, substituted or unsubstituted alkoxy group with 1 to 20 carbon atoms, substituted or unsubstituted aralkyl group with 7 to 30 carbon atoms, substituted or unsubstituted aroxy group with 6 to 30 carbon atoms, substituted or unsubstituted aryl group with 6 to 50 carbon atoms, substituted or unsubstituted heteroaryl group with 5 to 50 carbon atoms, substituted or unsubstituted arylamino group with 6 to 50 carbon atoms, and substituted or unsubstituted heteroarylamino group with 3 to 50 carbon atoms; and R 1 ~R 10 Two adjacent groups can bond together with the adjacent benzene ring to form one of the following: substituted or unsubstituted aryl group with 6-50 cyclic atoms, substituted or unsubstituted heteroaryl group with 5-50 cyclic atoms, and at least one hydrogen atom in the formed ring can be replaced by any one of the following: halogen atom, cyano group, substituted or unsubstituted silyl group, substituted or unsubstituted alkyl group with 1-20 carbon atoms, substituted or unsubstituted cycloalkyl group with 3-20 cyclic carbon atoms, substituted or unsubstituted alkoxy group with 1-20 carbon atoms, substituted or unsubstituted aralkyl group with 7-30 carbon atoms, substituted or unsubstituted aryloxy group with 6-30 cyclic carbon atoms, substituted or unsubstituted aryl group with 6-50 cyclic atoms, substituted or unsubstituted heteroaryl group with 5-50 cyclic atoms, substituted or unsubstituted arylamino group with 6-50 cyclic atoms, or substituted or unsubstituted heteroarylamino group with 3-50 cyclic atoms.

[0015] m is a positive integer, ranging from 0 to 5;

[0016] n is a positive integer, ranging from 1 to 3.

[0017] 5) The organic electroluminescent device according to any one of 1) to 3), wherein the organic molecule II of the light-emitting layer has a molecular structure as shown in general formulas S1 to S3:

[0018]

[0019] X represents O, S, and NR. 11 Or R 12 CR 13 ;

[0020] Ar 1 Ar 2 Ar 3 Each can be independently represented as one of the following: aryl group with 6-50 cyclic carbon atoms (substituted or unsubstituted), heteroaryl group with 5-50 cyclic atoms (substituted or unsubstituted), arylamine group with 6-50 cyclic atoms (substituted or unsubstituted), or heteroarylamine group with 3-50 cyclic atoms (substituted or unsubstituted); Ar 1 Ar2 Ar 3 Same or different;

[0021] R(R 1 ~R 13 ) represents one of the following: hydrogen atom, deuterium atom, tritium atom, halogen atom, cyano group, substituted or unsubstituted silyl group, substituted or unsubstituted alkyl group with 1 to 20 carbon atoms, substituted or unsubstituted cycloalkyl group with 3 to 20 carbon atoms, substituted or unsubstituted alkoxy group with 1 to 20 carbon atoms, substituted or unsubstituted aralkyl group with 7 to 30 carbon atoms, substituted or unsubstituted aroxy group with 6 to 30 carbon atoms, substituted or unsubstituted aryl group with 6 to 50 carbon atoms, substituted or unsubstituted heteroaryl group with 5 to 50 carbon atoms, substituted or unsubstituted arylamino group with 6 to 50 carbon atoms, and substituted or unsubstituted heteroarylamino group with 3 to 50 carbon atoms; and R 1 ~R 10 Two adjacent groups can bond together with the adjacent benzene ring to form one of the following: aryl group with 6-50 substituted or unsubstituted cyclic atoms, heteroaryl group with 5-50 substituted or unsubstituted cyclic atoms, and at least one hydrogen atom in the formed ring can be replaced by any one of the following: halogen atom, cyano group, substituted or unsubstituted silyl group, substituted or unsubstituted alkyl group with 1-20 carbon atoms, substituted or unsubstituted cycloalkyl group with 3-20 carbon atoms, substituted or unsubstituted alkoxy group with 1-20 carbon atoms, substituted or unsubstituted aralkyl group with 7-30 carbon atoms, substituted or unsubstituted aryloxy group with 6-30 carbon atoms, substituted or unsubstituted aryl group with 6-50 cyclic atoms, heteroaryl group with 5-50 substituted or unsubstituted arylamino group with 6-50 substituted or unsubstituted arylamino group with 3-50 substituted or unsubstituted cyclic atoms.

[0022] 6) The organic electroluminescent device according to any one of 1) to 3), wherein the organic molecule III of the light-emitting layer has a molecular structure as shown in general formulas D1 to D5:

[0023]

[0024] Ar 1 and Ar 2 Each and every one of the following can be independently represented: aryl group with 6-50 carbon atoms (substituted or unsubstituted), heteroaryl group with 5-50 cyclic atoms (substituted or unsubstituted), arylamine group with 6-50 cyclic atoms (substituted or unsubstituted), or heteroarylamine group with 3-50 cyclic atoms (substituted or unsubstituted); Ar 1 and Ar 2 Same or different;

[0025] R(R 1 ~R 16Each of the following groups independently represents one of the following: hydrogen atom, deuterium atom, tritium atom, halogen atom, cyano group, substituted or unsubstituted silyl group, substituted or unsubstituted alkyl group with 1 to 20 carbon atoms, substituted or unsubstituted cycloalkyl group with 3 to 20 carbon atoms, substituted or unsubstituted alkoxy group with 1 to 20 carbon atoms, substituted or unsubstituted aralkyl group with 7 to 30 carbon atoms, substituted or unsubstituted aroxy group with 6 to 30 carbon atoms, substituted or unsubstituted aryl group with 6 to 50 cyclic atoms, substituted or unsubstituted heteroaryl group with 5 to 50 cyclic atoms, substituted or unsubstituted arylamino group with 6 to 50 cyclic atoms, and substituted or unsubstituted heteroarylamino group with 3 to 50 cyclic atoms; and R 1 ~R 10 Two adjacent groups can bond together with the adjacent benzene ring to form one of the following: aryl group with 6-50 substituted or unsubstituted cyclic atoms, heteroaryl group with 5-50 substituted or unsubstituted cyclic atoms, and at least one hydrogen atom in the formed ring can be replaced by any one of the following: halogen atom, cyano group, substituted or unsubstituted silyl group, substituted or unsubstituted alkyl group with 1-20 carbon atoms, substituted or unsubstituted cycloalkyl group with 3-20 carbon atoms, substituted or unsubstituted alkoxy group with 1-20 carbon atoms, substituted or unsubstituted aralkyl group with 7-30 carbon atoms, substituted or unsubstituted aryloxy group with 6-30 carbon atoms, substituted or unsubstituted aryl group with 6-50 cyclic atoms, heteroaryl group with 5-50 substituted or unsubstituted arylamino group with 6-50 substituted or unsubstituted arylamino group with 3-50 substituted or unsubstituted cyclic atoms.

[0026] Compared with the prior art, the present invention has the following beneficial technical effects:

[0027] Because OLEDs operate at high current density in their emissive layer, the emissive layer is consistently in a state of high exciton concentration. High exciton concentration leads to various side reactions, such as singlet-singlet annihilation and singlet-polaron annihilation, resulting in reduced device efficiency, accelerated aging, and decreased device stability. Increasing the radiative rate of the luminescent molecules can significantly improve exciton utilization, ensuring that the OLED maintains a low exciton concentration even under high current density operation, fundamentally reducing the aforementioned side reactions and thus improving device efficiency and stability. However, currently, molecules with ultra-high radiative rates have very broad spectra, and using only these as guest molecules obviously cannot achieve ideal color purity. Therefore, this invention simultaneously introduces sensitizing molecules with ultra-high radiative rates and guest molecules with narrow-spectrum emission into the emitting layer. By selecting host molecules, sensitizing molecules, and guest molecules with appropriate energy levels, a dual energy transfer process from the host to the sensitizing molecule to the guest molecule is achieved. This not only greatly improves exciton utilization by introducing sensitizing molecules with ultra-high radiative rates and reduces the exciton density of the OLED emitting layer during operation, thus improving the efficiency and stability of the device, but also narrows the device spectrum through guest molecules with narrow-spectrum emission, resulting in ideal color purity. Attached Figure Description

[0028] Figure 1 This is a schematic diagram showing the structure of an organic electroluminescent device.

[0029] Figure 2 This is the absolute quantum yield test curve for DPAVBi.

[0030] Figure 3 This is the fluorescence lifetime decay curve of DPAVBi.

[0031] Figure 4 This is the fluorescence spectrum of TpBIBC-4MeS.

[0032] Figure 5 This is the voltage-current-brightness curve of the device in Example 1.

[0033] Figure 6 This is the electroluminescence spectrum of the device in Example 1.

[0034] Figure 7 This is the current density-external quantum efficiency characteristic curve of the device in Example 1.

[0035] Figure 8 This is a comparison diagram of the electroluminescence spectra of the devices in Comparative Example 1 and Example 1.

[0036] Figure 9 These are the current density-external quantum efficiency characteristic curves of the devices in Comparative Example 1 and Example 1.

[0037] Figure 10This is a comparison diagram of the electroluminescence spectra of the devices in Comparative Example 2 and Example 1.

[0038] Figure 11 These are the current density-external quantum efficiency characteristic curves of the devices in Comparative Example 2 and Example 1.

[0039] Figure 12 The devices of Example 1, Comparative Example 1, and Comparative Example 2 are at 1000 cd / m 2 A comparison chart of lifespan under different brightness levels. Detailed Implementation

[0040] This invention provides an organic electroluminescent device that simultaneously improves device efficiency, color purity, and lifetime. To make the objectives, technical solutions, and effects of this invention clearer and more explicit, the invention is further described in detail below. The specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0041] In the embodiments of this invention, the fluorescence radiative rate and full width at half maximum (FWHM) of the organic materials play a crucial role. These concepts are described in detail below.

[0042] The fluorescence emission rate is the rate constant (k) for a substance to transition from an excited state back to the ground state and emit fluorescence, which can be expressed by:

[0043] Equation (B): k=Φ / τ

[0044] The calculation is performed, where Φ is the fluorescence quantum yield of the substance, defined as the ratio of the number of fluorescence photons emitted after the substance absorbs light to the number of photons of the absorbed excitation light. τ is the fluorescence lifetime of the substance, defined as the time required for the fluorescence intensity of the substance to drop to 1 / e of the maximum fluorescence intensity I0 at excitation after the excitation light is removed. Both the fluorescence quantum yield and lifetime can be measured using steady-state or transient fluorescence spectrometry.

[0045] Half-width at half-maximum (HWHM) is the width of a spectral peak at half its height. It is the distance between two points where a straight line drawn through the midpoint of the peak height intersects the two sides of the peak.

[0046] The present invention will be specifically described below with reference to preferred specific examples, but the scope of the present invention should not be limited by the following specific examples.

[0047] [Component Structure]

[0048] The organic electroluminescent blue light device of the present invention comprises an anode, a cathode, and an organic layer between the anode and the cathode. The organic layer includes at least a light-emitting layer, and the present invention has distinctive features in the composition of the light-emitting layer.

[0049] The organic layer can consist solely of a light-emitting layer, or it can have one or more organic layers in addition to the light-emitting layer. Other organic layers can be hole injection layers, hole transport layers, electron blocking layers, electron transport layers, electron injection layers, etc. Specific device structures are as follows: Figure 1 As shown in the diagram. 1 represents the substrate, 2 represents the anode, 3 represents the hole injection layer, 4 represents the hole transport layer, 5 represents the electron blocking layer, 6 represents the light-emitting layer, 7 represents the hole blocking layer, 8 represents the electron transport layer, 9 represents the electron injection layer, and 10 represents the cathode. The following provides a detailed description of each layer.

[0050] [Emitting Layer]

[0051] The light-emitting layer is a layer in which holes and electrons injected from the anode and cathode combine to generate excitons and emit light.

[0052] 1. A cathode, an anode, and at least one organic layer containing a light-emitting layer sandwiched between the two electrodes. The light-emitting layer comprises organic molecule I, organic molecule II, and organic molecule III, wherein organic molecule I is the host material, organic molecule II is the sensitizing material, and organic molecule III is the light-emitting material.

[0053] Formula (A):E S1 (Ⅰ)>E S1 (Ⅱ)>E S1 (III)

[0054] In the above formula, E S1 (Ⅰ) represents the lowest excited singlet state energy level of organic molecule Ⅰ, E S1 (Ⅱ) represents the lowest excited singlet state energy level of the organic molecule Ⅱ, E S1 (Ⅲ) represents the lowest excited singlet energy level of the organic molecule Ⅲ;

[0055] Among them, the fluorescence radiation rate constant of organic molecule II is 5*10 8 s -1 ~5*10 10 s -1 between.

[0056] In this invention, the light-emitting layer comprises organic molecule I, organic molecule II, and organic molecule III satisfying the following formula (A), wherein organic molecule I is the host material, organic molecule II is the sensitizing material, and organic molecule III is the light-emitting material.

[0057] Formula (A):E S1 (Ⅰ)>E S1 (Ⅱ)>E S1 (III)

[0058] In the above formula, E S1 (Ⅰ) represents the lowest excited singlet state energy level of organic molecule Ⅰ, ES1 (Ⅱ) represents the lowest excited singlet state energy level of the organic molecule Ⅱ, E S1 (Ⅲ) represents the lowest excited singlet energy level of the organic molecule Ⅲ;

[0059] Among them, the fluorescence radiation rate constant of organic molecule II is 5*10 8 s -1 ~5*10 10 s -1 In this way, the excitons of the luminescent layer can be quickly consumed to obtain high luminescence efficiency. Furthermore, organic molecules III with a full width at half maximum (FWHM) between 5 and 40 nm are selected, and the luminescence of the organic molecules is converted into a narrow spectrum through the Foster energy resonance transfer process, thereby improving the color purity of the device.

[0060] As a preferred host material, unless otherwise specified, molecules represented by the following general formulas H1 to H6 may be preferred as organic molecule I.

[0061]

[0062] Ar 1 and Ar 2 Each can be independently represented as one of the following: aryl group with 6-50 cyclic carbon atoms (substituted or unsubstituted), heteroaryl group with 5-50 cyclic atoms (substituted or unsubstituted), arylamine group with 6-50 cyclic atoms (substituted or unsubstituted), or heteroarylamine group with 3-50 cyclic atoms (substituted or unsubstituted); Ar 1 and Ar 2 Same or different;

[0063] R(R 1 ~R 10 Ra) represents one of the following: hydrogen atom, deuterium atom, tritium atom, halogen atom, cyano group, substituted or unsubstituted silyl group, substituted or unsubstituted alkyl group with 1 to 20 carbon atoms, substituted or unsubstituted cycloalkyl group with 3 to 20 carbon atoms, substituted or unsubstituted alkoxy group with 1 to 20 carbon atoms, substituted or unsubstituted aralkyl group with 7 to 30 carbon atoms, substituted or unsubstituted aroxy group with 6 to 30 carbon atoms, substituted or unsubstituted aryl group with 6 to 50 carbon atoms, substituted or unsubstituted heteroaryl group with 5 to 50 carbon atoms, substituted or unsubstituted arylamino group with 6 to 50 carbon atoms, and substituted or unsubstituted heteroarylamino group with 3 to 50 carbon atoms; and R 1 ~R 10Two adjacent groups can bond together with the adjacent benzene ring to form one of the following: substituted or unsubstituted aryl group with 6-50 cyclic atoms, substituted or unsubstituted heteroaryl group with 5-50 cyclic atoms, and at least one hydrogen atom in the formed ring can be replaced by any one of the following: halogen atom, cyano group, substituted or unsubstituted silyl group, substituted or unsubstituted alkyl group with 1-20 carbon atoms, substituted or unsubstituted cycloalkyl group with 3-20 cyclic carbon atoms, substituted or unsubstituted alkoxy group with 1-20 carbon atoms, substituted or unsubstituted aralkyl group with 7-30 carbon atoms, substituted or unsubstituted aryloxy group with 6-30 cyclic carbon atoms, substituted or unsubstituted aryl group with 6-50 cyclic atoms, substituted or unsubstituted heteroaryl group with 5-50 cyclic atoms, substituted or unsubstituted arylamino group with 6-50 cyclic atoms, or substituted or unsubstituted heteroarylamino group with 3-50 cyclic atoms.

[0064] m is a positive integer, ranging from 0 to 5;

[0065] n is a positive integer, ranging from 1 to 3;

[0066] Hereinafter, specific examples of molecules represented by general formulas H1 to H6 are shown. However, the molecules represented by general formulas H1 to H6 that can be used in this invention should not be limited to these specific examples.

[0067]

[0068]

[0069]

[0070]

[0071]

[0072]

[0073]

[0074]

[0075]

[0076] As a preferred sensitizing material, unless otherwise specified, molecules represented by the following general formulas S1 to S3 can preferably be used as organic molecule II.

[0077]

[0078]

[0079] X represents O, S, and NR. 11 Or R12 CR 13 ;

[0080] Ar 1 Ar 2 Ar 3 Each can be independently represented as one of the following: aryl group with 6-50 cyclic carbon atoms (substituted or unsubstituted), heteroaryl group with 5-50 cyclic atoms (substituted or unsubstituted), arylamine group with 6-50 cyclic atoms (substituted or unsubstituted), or heteroarylamine group with 3-50 cyclic atoms (substituted or unsubstituted); Ar 1 Ar 2 Ar 3 Same or different;

[0081] R(R 1 ~R 13 ) represents one of the following: hydrogen atom, deuterium atom, tritium atom, halogen atom, cyano group, substituted or unsubstituted silyl group, substituted or unsubstituted alkyl group with 1 to 20 carbon atoms, substituted or unsubstituted cycloalkyl group with 3 to 20 carbon atoms, substituted or unsubstituted alkoxy group with 1 to 20 carbon atoms, substituted or unsubstituted aralkyl group with 7 to 30 carbon atoms, substituted or unsubstituted aroxy group with 6 to 30 carbon atoms, substituted or unsubstituted aryl group with 6 to 50 carbon atoms, substituted or unsubstituted heteroaryl group with 5 to 50 carbon atoms, substituted or unsubstituted arylamino group with 6 to 50 carbon atoms, and substituted or unsubstituted heteroarylamino group with 3 to 50 carbon atoms; and R 1 ~R 10 Two adjacent groups can bond together with the adjacent benzene ring to form one of the following: aryl group with 6-50 substituted or unsubstituted cyclic atoms, heteroaryl group with 5-50 substituted or unsubstituted cyclic atoms, and at least one hydrogen atom in the formed ring can be replaced by any one of the following: halogen atom, cyano group, substituted or unsubstituted silyl group, substituted or unsubstituted alkyl group with 1-20 carbon atoms, substituted or unsubstituted cycloalkyl group with 3-20 carbon atoms, substituted or unsubstituted alkoxy group with 1-20 carbon atoms, substituted or unsubstituted aralkyl group with 7-30 carbon atoms, substituted or unsubstituted aryloxy group with 6-30 carbon atoms, substituted or unsubstituted aryl group with 6-50 cyclic atoms, heteroaryl group with 5-50 substituted or unsubstituted arylamino group with 6-50 substituted or unsubstituted arylamino group with 3-50 substituted or unsubstituted cyclic atoms.

[0082] Hereinafter, specific examples of molecules represented by general formulas S1 to S3 are shown. However, the molecules represented by general formulas S1 to S3 that can be used in this invention should not be limited to these specific examples.

[0083]

[0084]

[0085]

[0086]

[0087]

[0088]

[0089]

[0090] As a preferred luminescent material, unless otherwise specified, molecules represented by the following general formulas D1 to D5 can preferably be used as organic molecule III.

[0091]

[0092] Ar 1 and Ar 2 Each and every one of the following can be independently represented: aryl group with 6-50 carbon atoms (substituted or unsubstituted), heteroaryl group with 5-50 cyclic atoms (substituted or unsubstituted), arylamine group with 6-50 cyclic atoms (substituted or unsubstituted), or heteroarylamine group with 3-50 cyclic atoms (substituted or unsubstituted); Ar 1 and Ar 2 Same or different;

[0093] R(R 1 ~R 16 Each of the following groups independently represents one of the following: hydrogen atom, deuterium atom, tritium atom, halogen atom, cyano group, substituted or unsubstituted silyl group, substituted or unsubstituted alkyl group with 1 to 20 carbon atoms, substituted or unsubstituted cycloalkyl group with 3 to 20 carbon atoms, substituted or unsubstituted alkoxy group with 1 to 20 carbon atoms, substituted or unsubstituted aralkyl group with 7 to 30 carbon atoms, substituted or unsubstituted aroxy group with 6 to 30 carbon atoms, substituted or unsubstituted aryl group with 6 to 50 cyclic atoms, substituted or unsubstituted heteroaryl group with 5 to 50 cyclic atoms, substituted or unsubstituted arylamino group with 6 to 50 cyclic atoms, and substituted or unsubstituted heteroarylamino group with 3 to 50 cyclic atoms; and R 1 ~R 10Two adjacent groups can bond together with the adjacent benzene ring to form one of the following: aryl group with 6-50 substituted or unsubstituted cyclic atoms, heteroaryl group with 5-50 substituted or unsubstituted cyclic atoms, and at least one hydrogen atom in the formed ring can be replaced by any one of the following: halogen atom, cyano group, substituted or unsubstituted silyl group, substituted or unsubstituted alkyl group with 1-20 carbon atoms, substituted or unsubstituted cycloalkyl group with 3-20 carbon atoms, substituted or unsubstituted alkoxy group with 1-20 carbon atoms, substituted or unsubstituted aralkyl group with 7-30 carbon atoms, substituted or unsubstituted aryloxy group with 6-30 carbon atoms, substituted or unsubstituted aryl group with 6-50 cyclic atoms, heteroaryl group with 5-50 substituted or unsubstituted arylamino group with 6-50 substituted or unsubstituted arylamino group with 3-50 substituted or unsubstituted cyclic atoms.

[0094] Hereinafter, specific examples of molecules represented by general formulas D1 to D5 are shown. However, the molecules represented by general formulas D1 to D5 that can be used in this invention should not be limited to these specific examples.

[0095]

[0096]

[0097]

[0098]

[0099]

[0100]

[0101]

[0102]

[0103]

[0104]

[0105]

[0106]

[0107]

[0108] [Substrate]

[0109] The OLED device of the present invention is supported by a substrate, which can be made of glass, transparent plastic, quartz, silicon, etc.

[0110] [anode]

[0111] Metals, alloys, and conductive molecules with a high work function (above 4 eV) can be used as the anode electrode material, such as metals like Au, CuI, indium tin oxide (ITO), SnO2, and ZnO, which are conductive and transparent materials. Alternatively, transparent amorphous materials such as IDIXO (In2O3-ZnO) can also be used.

[0112] [cathode]

[0113] Cathodes using metals, alloys, and conductive molecules with low work functions (below 4 eV) as electrode materials include sodium, sodium-potassium alloys, magnesium, lithium, magnesium / copper alloys, magnesium / silver alloys, magnesium / aluminum alloys, magnesium / indium alloys, aluminum / alumina (Al2O3) mixtures, indium, lithium / aluminum mixtures, and rare earth metals.

[0114] [Injection Layer]

[0115] The injection layer is a functional layer sandwiched between the electrode and the organic layer. It assists in the injection of holes from the anode or electrons from the cathode into the organic layer, thereby reducing the driving voltage and increasing the luminous brightness.

[0116] [Blocking Layer]

[0117] The blocking layer is a functional layer that blocks the diffusion of charge carriers (electrons or holes) and / or excitons from the light-emitting layer to the outside of the light-emitting layer, while simultaneously transporting charge carriers (electrons or holes).

[0118] [Cavity barrier]

[0119] The hole blocking layer serves the dual purpose of transporting electrons and blocking holes from entering the electron transport layer, thereby increasing the probability of exciton generation in the luminescent layer.

[0120] [Electron blocking layer]

[0121] The electron blocking layer serves both to transport holes and to block electrons from entering the hole transport layer, thereby increasing the probability of exciton generation in the luminescent layer.

[0122] Hole transport layer

[0123] The hole transport layer has the function of either hole injection or transport, or electron blocking, and can be either organic or inorganic, and can be a single layer or multiple layers.

[0124] [Electron transport layer]

[0125] The electron transport layer has the function of either electron injection or transport, or hole blocking, and can be either organic or inorganic, and can be a single layer or multiple layers.

[0126] Hereinafter, preferred molecules that can be used to fabricate devices are specifically illustrated, but the materials that can be used in this invention are not limited to the illustrated molecules. Furthermore, even molecules illustrated as materials with specific functions can be used as materials with other functions.

[0127] First, a list of preferred molecules that can be used as hole injection materials is provided.

[0128]

[0129] Secondly, a list of preferred molecules that can be used as hole transport materials is provided.

[0130]

[0131] Secondly, a list of preferred molecules that can be used as electron blocking materials is provided.

[0132]

[0133] Secondly, a list of preferred molecules that can be used as hole-blocking materials is provided.

[0134]

[0135] Secondly, a list of preferred molecules that can be used as electron transport materials is provided.

[0136]

[0137] Secondly, a list of preferred molecules that can be used as electron injection materials is provided.

[0138]

[0139] The organic electroluminescent element of this invention can be applied to any of the following: a single device, an array device, and a matrix device. The blue OLED of this invention can be applied to a variety of uses, such as manufacturing organic electroluminescent displays, lighting, or backlighting devices.

[0140] Example

[0141] The following examples further illustrate the features of the present invention. The materials, processing methods, processing order, etc., shown below can be appropriately modified without departing from the purpose of the present invention. The scope of the present invention is not limited by the specific examples shown below.

[0142] The luminescence performance was tested using the following equipment: steady-state fluorescence spectrometer (manufactured by Horiba: PTI QM40), transient fluorescence testing system (manufactured by Horiba: deltaflex-1), power meter (manufactured by Keithley: 2400 Series), luminance meter (manufactured by Beijing Normal University Optoelectronic Instrument Factory: ST-86LA), fiber optic spectrometer (manufactured by Avantes: UL2048CL-EVO-RS), and OLED aging lifetime tester (manufactured by Shanghai University: ZJLS-4).

[0143] The fluorescence emission rates and full width at half maximum (FWHM) of the molecules used in the examples and comparative examples were determined by the following method.

[0144] Fluorescence radiative rate: The molecule was dissolved in toluene solution at a concentration of 5.0 × 10⁻⁶. -5 The fluorescence quantum yield Φ of the sample was determined at room temperature using a QM40 quantum yield assay at a concentration of mol / L, with a xenon lamp as the excitation source. The fluorescence lifetime τ of the sample was then determined at room temperature using a deltaflex-1 excitation system, with a semiconductor laser at a wavelength of 370 nm and a full width at half maximum (FWHM) of 50 ps. The fluorescence radiative rate k of the molecule was calculated using equation (B).

[0145] Half-peak width: The molecule was dissolved in toluene solution at a concentration of 5.0 × 10⁻⁶. -5 The fluorescence spectrum of the sample was measured at room temperature using a QM40 excitation source, with a concentration of mol / L and an excitation source of xenon lamp. The vertical axis of the fluorescence spectrum represents the luminescence intensity, and the horizontal axis represents the wavelength. A straight line parallel to the horizontal axis was drawn through the midpoint of the peak height of the curve. The difference between the two points where this straight line intersects the curve is the half-width at half-maximum (WHM).

[0146] (Example 1) Device fabrication and characterization using BAN1 (organic molecule I), DPAVBi (organic molecule II), and TpBIBC-4Mes (organic molecule III)

[0147] The following molecules are prepared as materials for the luminescent layer.

[0148]

[0149] The QY of DPAVBi, measured by QM40, is 0.99, and the test curve is as follows. Figure 2 As shown, the fluorescence quantum yield is calculated by comparing the difference in fluorescence intensity area between the two spectra with the difference in absorption intensity area of ​​the excitation light. Figure 3 The fluorescence lifetime decay curve of DPAVBi is shown, with a fluorescence lifetime τ of 0.87 ns. The fluorescence radiative velocity of DPAVBi can be calculated from equation (B) as k = 1.14 × 10⁻⁶. -9 s -1This confirms that DPAVBi possesses an ultra-high fluorescence emission rate and can be used as a sensitizing molecule. The photoluminescence curve of TpBIBC-4Mes is shown below. Figure 4 As shown, the full width at half maximum (FWHM) of TpBIBC-4Mes obtained by the aforementioned method is 13 nm, and its emission spectrum is very narrow, making it suitable as a luminescent molecule.

[0150] The device fabrication process is as follows: Vacuum evaporation is performed at a vacuum degree of 5.0 × 10⁻⁶. -5 Functional layers were deposited on a glass substrate with indium tin oxide (ITO) as the anode. First, 10 nm of HATCN was deposited on the ITO, followed by 40 nm of HT002 and 5 nm of HT001. BAN1, DPAVBi, and TpBIBC-4Mes were co-deposited for 20 nm as the emitting layer from different evaporation sources. The concentrations of DPAVBi and TpBIBC-4Mes were both 2 wt%. Then, 5 nm of ET002 and 30 nm of ET001:Liq (1:1) were deposited sequentially. Finally, 1 nm of lithium fluoride (LiF) was deposited as the electron injection layer, and 100 nm of aluminum (Al) was deposited as the cathode to obtain an organic electroluminescent blue light device.

[0151] Figure 5 The voltage-current-brightness curve of the device. Figure 6 Electroluminescence spectrum Figure 7 The curve represents the current density versus external quantum efficiency.

[0152] Comparative Example 1-1: Device Fabrication and Characterization Using BAN1 and DPAVBi

[0153] The emitting layer was prepared using a BAN1 / DPAVBi evaporation source, resulting in a 2wt% DPAVBi doped film. All other layers were identical to those in Example 1. The emission spectrum and current density-external quantum efficiency characteristic curves of the resulting device are presented together with the test results from Example 1. Figure 8 , Figure 9 .

[0154] Comparative Examples 1-2: Device Fabrication and Characterization Using BAN1 and TpBIBC-4Mes

[0155] The emitting layer was prepared using a BAN1, TpBIBC-4Mes evaporation source, resulting in a 2wt% TpBIBC-4Mes doped film. All other layers were identical to those in Example 1. The emission spectrum and current density-external quantum efficiency curves of the resulting device are presented together with the test results from Example 1. Figure 10 , Figure 11 .

[0156] The devices of Example 1, Comparative Example 1, and Comparative Example 2 at 10 mA / cm 2The lifetime comparison at current density is shown in Figure 12 LT95 refers to the time it takes for the device's brightness to decay to 95% of its initial brightness at a constant current density of 20 mA / cm².

[0157] In Comparative Example 1-1, the device using the ultra-high radiative rate fluorescent molecule DPAVBi as the guest molecule achieved an ultra-high EQE of 15.3%, but the half-width at half-maximum (WHM) of the electroluminescence spectrum was 47 nm, with chromaticity coordinates of (0.137, 0.148), indicating poor color purity. In Comparative Example 1-2, the device using the ultra-narrow spectrum fluorescent molecule TpBIBC-4Mes as the guest molecule achieved a WHM of only 14 nm, with chromaticity coordinates of (0.134, 0.008), indicating excellent color purity, but the EQE was only 9.2%, resulting in low efficiency. Example 1, which combines both, using the ultra-high radiative rate fluorescent molecule DPAVBi as the sensitizer and the ultra-narrow spectrum fluorescent molecule TpBIBC-4Mes as the emitting molecule, achieved an ultra-high EQE of 15.1%, with a WHM of 16 nm and chromaticity coordinates of (0.134, 0.111). Its EQE was significantly improved compared to Comparative Example 2, almost equivalent to that of Comparative Example 1, and the color purity was also much improved compared to Comparative Example 1. This indicates that the device using the high-radiative-rate fluorescent molecule DPAVBi as the sensitizer and the ultra-narrow-spectrum fluorescent molecule TpBIBC-4Mes as the emitting molecule can improve both the device EQE and the spectrum, thereby improving color purity. The devices of Example 1, Comparative Example 1-1, and Comparative Example 1-2 achieved a EQE of 10 mA / cm². 2 The LT95 at different current densities were 74.3 h, 73.4 h, and 56 h, respectively. The device lifetimes of Example 1 and Comparative Example 1-1 were comparable, but significantly improved compared to Comparative Example 1-2. This indicates that the device lifetime is determined by the sensitized molecules, and the poor stability of narrow-spectrum luminescent molecules is overcome in the sensitized device. In summary, the data analysis shows that the device of the present invention can achieve both high efficiency and lifetime, as well as narrow-spectrum emission and improved color purity.

[0158] (Example 2) Device fabrication and characterization using DMPPP (organic molecule I), DPAVBi (organic molecule II), and TpBIBC-4Mes (organic molecule III).

[0159] The following molecules are prepared as materials for the luminescent layer.

[0160]

[0161] The fabrication process of the device is the same as in Example 1, except that the light-emitting layer is composed of DMPPP, DPAVBi, and TpBIBC-4Mes co-deposited at 20 nm from different evaporation sources as the light-emitting layer.

[0162] Comparative Example 2-1: Device Fabrication and Characterization Using DMPPP and DPAVBi

[0163] The light-emitting layer was prepared using a DMPPP and DPAVBi evaporation source to create an evaporation film with a DPAVBi doping content of 2wt%. Apart from this, all other layers were the same as in Example 1.

[0164] Comparative Example 2-2: Device Fabrication and Characterization Using DMPPP and TpBIBC-4Mes

[0165] The light-emitting layer was prepared using a DMPPP and TpBIBC-4Mes evaporation source to form an evaporation film with a TpBIBC-4Mes doping content of 2wt%. Apart from this, the other layers were the same as in Example 1.

[0166] (Example 3) Device fabrication and characterization using BAN1 (organic molecule I), N-BDAVBi (organic molecule II), and TpBIBC-4Mes (organic molecule III)

[0167] The following molecules are prepared as materials for the luminescent layer.

[0168]

[0169] The fabrication process of the device is the same as that in Example 1, except that the composition of the light-emitting layer is different: BAN1, N-BDAVBi and TpBIBC-4Mes are co-deposited for 20 nm from different evaporation sources as the light-emitting layer.

[0170] Comparative Example 3-1: Device Fabrication and Characterization Using BAN1 and DPAVBi

[0171] The light-emitting layer was prepared using a BAN1 and N-BDAVBi vapor deposition source to create an N-BDAVBi doped film with a content of 2 wt%. All other layers were the same as in Example 1.

[0172] Comparative Example 3-2: Device fabrication and characterization using BAN1 and TpBIBC-4Mes

[0173] The light-emitting layer was prepared using a BAN1 and TpBIBC-4Mes evaporation source to form an evaporation film with a TpBIBC-4Mes doping content of 2wt%. All other layers were the same as in Example 1.

[0174] (Example 4) Device fabrication and characterization using BAN1 (organic molecule I), DPAVBi (organic molecule II), and t-DABNA (organic molecule III)

[0175] The following molecules are prepared as materials for the luminescent layer.

[0176]

[0177] The fabrication process of the device is the same as in Example 1, except that the light-emitting layer is composed of BAN1, DPAVBi, and t-DABNA co-deposited at 20 nm from different evaporation sources as the light-emitting layer.

[0178] Comparative Example 4-1: Device Fabrication and Characterization Using BAN1 and DPAVBi

[0179] The light-emitting layer was prepared using a BAN1 and DPAVBi evaporation source to prepare an evaporation film with a DPAVBi doping content of 2wt%. All other layers were the same as in Example 1.

[0180] Comparative Example 4-2: Device Fabrication and Characterization Using BAN1 and t-DABNA

[0181] The light-emitting layer was prepared using a BAN1 and t-DABNA evaporation source to create an evaporation film with a t-DABNA doping content of 2wt%. All other layers were the same as in Example 1.

[0182] The device characteristic results of Examples 1-4 and Comparative Examples are listed in Table 1.

[0183] Table 1

[0184]

[0185] The photophysical properties of the molecules used in Examples 1-4 and the comparative examples are listed in Table 2.

[0186] Table 2

[0187]

[0188]

[0189] Note: S1 is the singlet state energy level, Φ is the fluorescence quantum yield, τ is the fluorescence lifetime, and k is the fluorescence energy level. f The fluorescence radiative rate is calculated using equation (B).

[0190] [Practicality]

[0191] The organic electroluminescent blue light device of the present invention exhibits good stability, high luminous efficiency, and high color purity, making it suitable for application in display devices. Therefore, the present invention has high industrial applicability.

Claims

1. An organic electroluminescent device, characterized in that: The device comprises a cathode, an anode, and at least one organic layer containing a light-emitting layer sandwiched between the two electrodes. The light-emitting layer comprises organic molecule I, organic molecule II, and organic molecule III, wherein organic molecule I is the host material, organic molecule II is the sensitizing material, and organic molecule III is the light-emitting material. Furthermore, organic molecule I, organic molecule II, and organic molecule III satisfy the condition represented by the following formula (A). Equation (A): E S1 (I) > E S1 (II) > E S1 (III) In the above formula (A), E S1 (Ⅰ) represents the lowest excited singlet state energy level of organic molecule Ⅰ, E S1 (Ⅱ) represents the lowest excited singlet state energy level of the organic molecule Ⅱ, E S1 (Ⅲ) represents the lowest excited singlet energy level of the organic molecule Ⅲ; Among them, the fluorescence radiation rate constant of organic molecule II is 5*10 8 s -1 ~5*10 10 s -1 Between these values, the full width at half maximum (FWHM) of organic molecule III is between 5 and 40 nm.

2. The organic electroluminescent device according to claim 1, characterized in that: Organic molecule III emits blue light, with a peak emission value between 440-490 nm.

3. The organic electroluminescent device according to claim 1 or 2, characterized in that: The mass content of organic molecule II in the light-emitting layer is between 0.5 wt% and 20 wt%, and the mass content of organic molecule III in the light-emitting layer is between 0.5 wt% and 20 wt%.

4. The organic electroluminescent device according to any one of claims 1 to 3, characterized in that: The organic molecule I of the luminescent layer has a molecular structure as shown in general formulas H1 to H6: Ar 1 and Ar 2 Each can be independently represented as one of the following: aryl group with 6-50 cyclic carbon atoms (substituted or unsubstituted), heteroaryl group with 5-50 cyclic atoms (substituted or unsubstituted), arylamine group with 6-50 cyclic atoms (substituted or unsubstituted), or heteroarylamine group with 3-50 cyclic atoms (substituted or unsubstituted); Ar 1 and Ar 2 Same or different; R(R 1 ~R 10 Ra) represents one of the following: hydrogen atom, deuterium atom, tritium atom, halogen atom, cyano group, substituted or unsubstituted silyl group, substituted or unsubstituted alkyl group with 1 to 20 carbon atoms, substituted or unsubstituted cycloalkyl group with 3 to 20 carbon atoms, substituted or unsubstituted alkoxy group with 1 to 20 carbon atoms, substituted or unsubstituted aralkyl group with 7 to 30 carbon atoms, substituted or unsubstituted aroxy group with 6 to 30 carbon atoms, substituted or unsubstituted aryl group with 6 to 50 carbon atoms, substituted or unsubstituted heteroaryl group with 5 to 50 carbon atoms, substituted or unsubstituted arylamino group with 6 to 50 carbon atoms, and substituted or unsubstituted heteroarylamino group with 3 to 50 carbon atoms; and R 1 ~R 10 Two adjacent groups can bond together with the adjacent benzene ring to form one of the following: substituted or unsubstituted aryl group with 6-50 cyclic atoms, substituted or unsubstituted heteroaryl group with 5-50 cyclic atoms, and at least one hydrogen atom in the formed ring can be replaced by any one of the following: halogen atom, cyano group, substituted or unsubstituted silyl group, substituted or unsubstituted alkyl group with 1-20 carbon atoms, substituted or unsubstituted cycloalkyl group with 3-20 cyclic carbon atoms, substituted or unsubstituted alkoxy group with 1-20 carbon atoms, substituted or unsubstituted aralkyl group with 7-30 carbon atoms, substituted or unsubstituted aryloxy group with 6-30 cyclic carbon atoms, substituted or unsubstituted aryl group with 6-50 cyclic atoms, substituted or unsubstituted heteroaryl group with 5-50 cyclic atoms, substituted or unsubstituted arylamino group with 6-50 cyclic atoms, or substituted or unsubstituted heteroarylamino group with 3-50 cyclic atoms. m is a positive integer, ranging from 0 to 5; n is a positive integer, ranging from 1 to 3.

5. The organic electroluminescent device according to any one of claims 1 to 3, characterized in that: The organic molecule II of the luminescent layer has a molecular structure as shown in general formulas S1 to S3: X represents O, S, and NR. 11 or R 12 CR 13 ; Ar 1 Ar 2 Ar 3 Each can be independently represented as one of the following: aryl group with 6-50 cyclic carbon atoms (substituted or unsubstituted), heteroaryl group with 5-50 cyclic atoms (substituted or unsubstituted), arylamine group with 6-50 cyclic atoms (substituted or unsubstituted), or heteroarylamine group with 3-50 cyclic atoms (substituted or unsubstituted); Ar 1 Ar 2 Ar 3 Same or different; R(R 1 ~R 13 ) represents one of the following: hydrogen atom, deuterium atom, tritium atom, halogen atom, cyano group, substituted or unsubstituted silyl group, substituted or unsubstituted alkyl group with 1 to 20 carbon atoms, substituted or unsubstituted cycloalkyl group with 3 to 20 carbon atoms, substituted or unsubstituted alkoxy group with 1 to 20 carbon atoms, substituted or unsubstituted aralkyl group with 7 to 30 carbon atoms, substituted or unsubstituted aroxy group with 6 to 30 carbon atoms, substituted or unsubstituted aryl group with 6 to 50 carbon atoms, substituted or unsubstituted heteroaryl group with 5 to 50 carbon atoms, substituted or unsubstituted arylamino group with 6 to 50 carbon atoms, and substituted or unsubstituted heteroarylamino group with 3 to 50 carbon atoms; and R 1 ~R 10 Two adjacent groups can bond together with the adjacent benzene ring to form one of the following: aryl group with 6-50 substituted or unsubstituted cyclic atoms, heteroaryl group with 5-50 substituted or unsubstituted cyclic atoms, and at least one hydrogen atom in the formed ring can be replaced by any one of the following: halogen atom, cyano group, substituted or unsubstituted silyl group, substituted or unsubstituted alkyl group with 1-20 carbon atoms, substituted or unsubstituted cycloalkyl group with 3-20 carbon atoms, substituted or unsubstituted alkoxy group with 1-20 carbon atoms, substituted or unsubstituted aralkyl group with 7-30 carbon atoms, substituted or unsubstituted aryloxy group with 6-30 carbon atoms, substituted or unsubstituted aryl group with 6-50 cyclic atoms, heteroaryl group with 5-50 substituted or unsubstituted arylamino group with 6-50 substituted or unsubstituted arylamino group with 3-50 substituted or unsubstituted cyclic atoms.

6. The organic electroluminescent device according to any one of claims 1 to 3, characterized in that: The organic molecule III of the luminescent layer has a molecular structure as shown in general formulas D1 to D5: Ar 1 and Ar 2 Each and every one of the following can be independently represented: aryl group with 6-50 carbon atoms (substituted or unsubstituted), heteroaryl group with 5-50 cyclic atoms (substituted or unsubstituted), arylamine group with 6-50 cyclic atoms (substituted or unsubstituted), or heteroarylamine group with 3-50 cyclic atoms (substituted or unsubstituted); Ar 1 and Ar 2 Same or different; R(R 1 ~R 16 Each of the following groups independently represents one of the following: hydrogen atom, deuterium atom, tritium atom, halogen atom, cyano group, substituted or unsubstituted silyl group, substituted or unsubstituted alkyl group with 1 to 20 carbon atoms, substituted or unsubstituted cycloalkyl group with 3 to 20 carbon atoms, substituted or unsubstituted alkoxy group with 1 to 20 carbon atoms, substituted or unsubstituted aralkyl group with 7 to 30 carbon atoms, substituted or unsubstituted aroxy group with 6 to 30 carbon atoms, substituted or unsubstituted aryl group with 6 to 50 cyclic atoms, substituted or unsubstituted heteroaryl group with 5 to 50 cyclic atoms, substituted or unsubstituted arylamino group with 6 to 50 cyclic atoms, and substituted or unsubstituted heteroarylamino group with 3 to 50 cyclic atoms; and R 1 ~R 10 Two adjacent groups can bond together with the adjacent benzene ring to form one of the following: aryl group with 6-50 substituted or unsubstituted cyclic atoms, heteroaryl group with 5-50 substituted or unsubstituted cyclic atoms, and at least one hydrogen atom in the formed ring can be replaced by any one of the following: halogen atom, cyano group, substituted or unsubstituted silyl group, substituted or unsubstituted alkyl group with 1-20 carbon atoms, substituted or unsubstituted cycloalkyl group with 3-20 carbon atoms, substituted or unsubstituted alkoxy group with 1-20 carbon atoms, substituted or unsubstituted aralkyl group with 7-30 carbon atoms, substituted or unsubstituted aryloxy group with 6-30 carbon atoms, substituted or unsubstituted aryl group with 6-50 cyclic atoms, heteroaryl group with 5-50 substituted or unsubstituted arylamino group with 6-50 substituted or unsubstituted arylamino group with 3-50 substituted or unsubstituted cyclic atoms.

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