An organic compound containing boron and nitrogen and its application in organic electroluminescent devices

Abstract

Disclosed herein are boron-nitrogen-containing organic compounds and their use in organic electroluminescent devices. The structure of the boron-nitrogen-containing organic compound is shown in Formula 1. By introducing a silicon-containing substituent into the planar molecular skeleton, the silicon-containing substituent prevents overlap between dopant materials and / or overlap between the dopant material and the host material, thereby shortening the lifetime of triplet excitons, thereby improving the luminous efficiency and / or extending the life of the organic electroluminescent device. Furthermore, the silicon-containing substituent has little effect on the highest occupied molecular orbital, lowest unoccupied molecular orbital, triplet state, and singlet state of the boron-nitrogen-containing organic compound. Furthermore, because silicon-carbon bonds are longer than carbon-carbon bonds, the silicon-containing substituent can occupy a wider space, thereby giving the boron-nitrogen-containing organic compound a more three-dimensional structure. This more three-dimensional structure improves the luminous efficiency and life of the organic electroluminescent device.

Description

Technical Field

[0001] The present disclosure belongs to the technical field of organic electroluminescent devices, and in particular relates to an organic compound containing boron and nitrogen and an application thereof in an organic electroluminescent device. Background Art

[0002] In organic electroluminescent devices, the organic functional layer materials have evolved from fluorescent materials to phosphorescent materials and then to thermally activated delayed fluorescence (TADF) materials. TADF materials are materials that capture triplet excitons into singlet excitons by controlling the singlet-triplet splitting energy (ΔEst). This energy difference (ΔEst) is small enough to convert triplet excitons into singlet excitons via reverse intersystem crossing (RISC).

[0003] In the related art, TADF materials that introduce boron and nitrogen atoms (TADF materials of the BN series) have a high planarity of molecular structure. When used in organic electroluminescent devices, large overlaps are likely to occur between dopant materials or between dopant materials and host materials. Therefore, their triplet excitons are relatively stable. At the same time, the lifetime of triplet excitons increases, resulting in a decrease in the luminous efficiency or a shortened lifetime of the organic electroluminescent device, which limits the application of BN series TADF materials in organic electroluminescent devices.

[0004] It should be noted that the information disclosed in the above background technology section is only used to enhance the understanding of the background of the present disclosure, and therefore may include information that does not constitute prior art known to ordinary technicians in the field. Summary of the Invention

[0005] By utilizing one or more embodiments of the present disclosure, the technical problems of low luminous efficiency or short life of BN series TADF materials can be solved to a certain extent.

[0006] The present application provides an organic compound containing boron and nitrogen. The structure of the organic compound containing boron and nitrogen is shown in Formula 1:

[0007]

[0008] in,

[0009] R1~R 12 At least one of them is a silicon-containing substituent;

[0010] R1~R 12 The same or different radicals are each independently selected from hydrogen, a substituted or unsubstituted alkyl group having 1 to 40 carbon atoms, a substituted or unsubstituted aryl group having 6 to 40 carbon atoms, a substituted or unsubstituted heteroaryl group having 5 to 60 carbon atoms, a substituted or unsubstituted fluorenyl group, a substituted or unsubstituted heterofluorenyl group, a substituted or unsubstituted aryloxy group having 6 to 60 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 39 carbon atoms, a substituted or unsubstituted aromatic group having 6 to 39 carbon atoms, an amino group, a substituted or unsubstituted cycloalkyl group having 3 to 39 carbon atoms, a substituted or unsubstituted heterocycloalkyl group having 3 to 39 carbon atoms, a substituted or unsubstituted alkylsilyl group having 1 to 39 carbon atoms, a substituted or unsubstituted alkylboryl group having 1 to 39 carbon atoms, a substituted or unsubstituted arylboryl group having 6 to 39 carbon atoms, a substituted or unsubstituted arylphosphino group having 6 to 39 carbon atoms, and a substituted or unsubstituted arylsilyl group having 6 to 39 carbon atoms;

[0011] R1 and R2 are bonded to form a ring, fused to form a ring, or are not bonded to form a ring; R3 and R4 are bonded to form a ring, fused to form a ring, or are not bonded to form a ring; R5 and R6 are bonded to form a ring, fused to form a ring, or are not bonded to form a ring; R7 and R8 are bonded to form a ring, fused to form a ring, or are not bonded to form a ring; R9 and R 10 Bonded to form a ring, fused to form a ring or not, R 11 and R 12 Bonded to form a ring, fused to form a ring, or uncyclic;

[0012] X1~X 12 are the same as or different from each other and are independently selected from CH and N, X 10 ~X 12 At least one of them is N;

[0013] R1~R 12 、X1~X 12 The hydrogen in the hydrogen is selected from any one or more of protium, deuterium and tritium.

[0014] As an optional embodiment, in the general formula 1, R1 to R 12 Each is independently selected from substituents containing 1 to 4 aromatic rings and / or aromatic heterocycles.

[0015] As an optional embodiment, in the general formula 1, R1 and R2 are bonded to form a 5-8 membered ring, and / or, R3 and R4 are bonded to form a 5-8 membered ring, and / or, R5 and R6 are bonded to form a 5-8 membered ring, and / or, R7 and R8 are bonded to form a 5-8 membered ring, and / or, R9 and R 10 bonded to form a 5- to 8-membered ring, and / or, R 11 and R 12 Bonded into 5- to 8-membered rings.

[0016] As an optional embodiment, in the general formula 1, X1, X3, X4, X5, X8, X9, X 10 、X 11 and X 12 are the same as or different from each other and are each independently selected from CD and N.

[0017] As an optional embodiment, in the general formula 1, X2, X6 and X7 are the same as or different from each other, and are independently selected from CD and N.

[0018] As an optional embodiment, the structure of the organic compound containing boron and nitrogen is shown in Formula 2 or Formula 3:

[0019]

[0020] Wherein, in the general formula 2 and the general formula 3, R1 to R 12 、X1~X 12 The definitions of are the same as those in the general formula 1.

[0021] As an optional embodiment, the singlet energy level (E S1 ) and triplet energy level (E T1 ) energy level difference (ΔE st ) is greater than 0eV and less than 1.0eV.

[0022] As an optional embodiment, the organic compound containing boron and nitrogen meets the following conditions:

[0023] The triplet energy level (E T1 ) is greater than or equal to 2.60 eV;

[0024] The triplet excitation wavelength (λ T1 ) is less than or equal to 480 nm; and

[0025] HOMO orbital energy level (E HOMO ) is greater than or equal to 4.60eV.

[0026] As an optional embodiment, the organic compound containing boron and nitrogen is represented by any one of Formulas 1 to 30:

[0027]

[0028]

[0029]

[0030]

[0031]

[0032] An organic electroluminescent device proposed in an embodiment of the present application includes at least one functional layer containing the above-mentioned organic compound containing boron and nitrogen.

[0033] As an optional embodiment, the functional layer includes a light-emitting layer, and the light-emitting layer contains at least one of the above-mentioned organic compounds containing boron and nitrogen.

[0034] As an optional embodiment, the light-emitting layer includes a host material and the organic compound containing boron and nitrogen, and the mass ratio of the host material to the organic compound containing boron and nitrogen is (50-90):(0-5).

[0035] As an optional embodiment, the light-emitting layer also includes a functional material, and the functional material serves as a doping material or a co-doping material, and the mass ratio of the main material, the organic compound containing boron and nitrogen, and the functional material is (50-90):(0-5):(10-40).

[0036] As an optional embodiment, the functional material is selected from the compound shown in Formula 31 or Formula 32:

[0037]

[0038] As an optional embodiment, the organic electroluminescent device includes an electron injection layer, an electron transport layer and / or a hole blocking layer, the light-emitting layer, the electron blocking layer and / or the hole transport layer, and the hole injection layer stacked in sequence, the thickness of the electron injection layer is 0nm to 3nm, the thickness of the electron transport layer is 20nm to 40nm, the thickness of the hole blocking layer is 0nm to 10nm, the thickness of the light-emitting layer is 20nm to 40nm, the thickness of the electron blocking layer is 0nm to 10nm, the thickness of the hole transport layer is 100nm to 200nm, and the thickness of the hole injection layer is 0nm to 10nm.

[0039] An embodiment of the present application provides a lighting or display device, which includes the above-mentioned organic electroluminescent device.

[0040] The embodiments of the present application have at least the following beneficial effects:

[0041] The boron-nitrogen-containing organic compound proposed in the embodiments of the present disclosure introduces a silicon-containing substituent into the planar molecular skeleton. The silicon-containing substituent prevents overlap between dopants and / or overlap between dopants and host materials, thereby shortening the lifetime of triplet excitons, thereby improving the luminous efficiency and / or extending the life of the organic electroluminescent device. At the same time, the silicon-containing substituent has little effect on the highest occupied molecular orbital (HOMO), lowest unoccupied molecular orbital (LUMO), triplet state (T1), and singlet state (S1) of the boron-nitrogen-containing organic compound. Moreover, since the silicon-carbon bond (Si-C) is longer than the carbon-carbon bond (CC), the silicon-containing substituent can occupy a wider space, thereby giving the boron-nitrogen-containing organic compound a more three-dimensional structure, thereby improving the luminous efficiency and life of the organic electroluminescent device through the more three-dimensional structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure, a brief introduction will be given below to the drawings required for use in the description of the embodiments. Obviously, the drawings described below are some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0043] Figure 1 shows a schematic cross-sectional structure diagram of an organic electroluminescent device in an embodiment of the present disclosure;

[0044] Figure 2 The schematic diagram of the structure of the organic compound containing boron and nitrogen as shown in Formula 3 in the embodiment of the present disclosure is shown;

[0045] Figure 3 Schematic diagram of the HOMO orbital of the organic compound containing boron and nitrogen as shown in Formula 3 in an embodiment of the present disclosure is shown;

[0046] Figure 4 A schematic diagram of the LUMO orbital of the organic compound containing boron and nitrogen as shown in Formula 3 in an embodiment of the present disclosure is shown.

[0047] Reference numerals:

[0048] 100, cathode; 200, electron injection layer; 300, electron transport layer; 400, hole blocking layer; 500, light-emitting layer; 600, electron blocking layer; 700, hole transport layer; 800, hole injection layer; 900, anode. DETAILED DESCRIPTION

[0049] The following will be combined with the accompanying drawings in the embodiments of the present disclosure to clearly and completely describe the technical solutions in the embodiments of the present disclosure. Obviously, the embodiments described are only part of the embodiments of the present disclosure, not all of the embodiments. Based on the embodiments of the present disclosure, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present disclosure.

[0050] In addition, the present disclosure may repeat reference numbers and / or reference letters in different examples. This repetition is for the purpose of simplicity and clarity and does not in itself indicate the relationship between the various embodiments and / or arrangements discussed. In addition, the present disclosure provides examples of various specific processes and materials, but those skilled in the art will recognize the application of other processes and / or the use of other materials.

[0051] The present disclosure is described below with reference to specific embodiments and in conjunction with the accompanying drawings:

[0052] An organic compound containing boron and nitrogen is proposed in an embodiment of the present disclosure. The structure of the organic compound containing boron and nitrogen is shown in Formula 1:

[0053]

[0054] in,

[0055] R1~R 12 At least one of them is a silicon-containing substituent;

[0056] R1~R 12 The same or different radicals are each independently selected from hydrogen, a substituted or unsubstituted alkyl group having 1 to 40 carbon atoms, a substituted or unsubstituted aryl group having 6 to 40 carbon atoms, a substituted or unsubstituted heteroaryl group having 5 to 60 carbon atoms, a substituted or unsubstituted fluorenyl group, a substituted or unsubstituted heterofluorenyl group, a substituted or unsubstituted aryloxy group having 6 to 60 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 39 carbon atoms, a substituted or unsubstituted aromatic group having 6 to 39 carbon atoms, an amino group, a substituted or unsubstituted cycloalkyl group having 3 to 39 carbon atoms, a substituted or unsubstituted heterocycloalkyl group having 3 to 39 carbon atoms, a substituted or unsubstituted alkylsilyl group having 1 to 39 carbon atoms, a substituted or unsubstituted alkylboryl group having 1 to 39 carbon atoms, a substituted or unsubstituted arylboryl group having 6 to 39 carbon atoms, a substituted or unsubstituted arylphosphino group having 6 to 39 carbon atoms, and a substituted or unsubstituted arylsilyl group having 6 to 39 carbon atoms;

[0057] R1 and R2 are bonded to form a ring, fused to form a ring, or are not bonded to form a ring; R3 and R4 are bonded to form a ring, fused to form a ring, or are not bonded to form a ring; R5 and R6 are bonded to form a ring, fused to form a ring, or are not bonded to form a ring; R7 and R8 are bonded to form a ring, fused to form a ring, or are not bonded to form a ring; R9 and R10 Bonded to form a ring, fused to form a ring or not, R 11 and R 12 Bonded to form a ring, fused to form a ring, or uncyclic;

[0058] X1~X 12 are the same as or different from each other and are independently selected from CH and N, X 10 ~X 12 At least one of them is N;

[0059] R1~R 12 、X1~X 12 The hydrogen in the hydrogen is selected from any one or more of protium, deuterium and tritium.

[0060] The boron-nitrogen-containing organic compound proposed in the embodiments of the present disclosure introduces a silicon-containing substituent into the planar molecular skeleton. The silicon-containing substituent prevents overlap between dopants and / or overlap between dopants and host materials, thereby shortening the lifetime of triplet excitons, thereby improving the luminous efficiency and / or extending the life of the organic electroluminescent device. At the same time, the silicon-containing substituent has little effect on the highest occupied molecular orbital (HOMO), lowest unoccupied molecular orbital (LUMO), triplet state (T1), and singlet state (S1) of the boron-nitrogen-containing organic compound. Moreover, since the silicon-carbon bond (Si-C) is longer than the carbon-carbon bond (CC), the silicon-containing substituent can occupy a wider space, thereby giving the boron-nitrogen-containing organic compound a more three-dimensional structure, thereby improving the luminous efficiency and life of the organic electroluminescent device through the more three-dimensional structure.

[0061] TADF materials are the third generation of organic light-emitting materials developed after organic fluorescent materials and organic phosphorescent materials. TADF materials generate electrons and holes under electric field excitation, and singlet excitons and triplet excitons are generated by the combination of electrons and holes. Excitons decay through transient fluorescence radiation. At the same time, this type of material has a small energy level difference between singlet and triplet states (ΔE st ), low-energy triplet excitons are converted to singlet excitons by thermal activation through internal reverse intersystem crossing (RISC), emitting delayed fluorescence (DF), a typical E-type TADF process. TADF materials can achieve a small singlet-triplet energy difference (ΔEST) through the spatial separation of the HOMO and LUMO electron cloud density distributions, satisfying the energy level conditions for efficient reverse intersystem crossing (RISC).

[0062] Based on the principles of quantum statistics, when TADF is electronically excited, 75% of the excited states are in the triplet state and 25% are in the singlet state. While triplet excitons emit transient fluorescence, they can also be thermally activated to convert to singlet excitons, emitting delayed fluorescence. This fully utilizes both singlet and triplet excitons formed under electrical excitation, enabling the device's internal quantum efficiency to reach 100%.

[0063] However, when traditional TADF materials are used as emitters in organic electroluminescent devices, the intrinsic reflection spectrum of TADF materials is relatively wide. For example, the half-width of a typical TADF material is 80nm to 100nm, which will result in relatively low color purity and cannot meet the display requirements of organic electroluminescent devices.

[0064] To address the defect of traditional TADF materials, which have a wide intrinsic reflection spectrum and result in low color purity that cannot meet display requirements, boron and nitrogen atoms can be introduced into the TADF material for doping, and combined with adjacent phenyl groups to construct a rigid polycyclic aromatic skeleton, forming the BN series of multiple resonance TADF (MR-TADF) materials. Due to the opposite resonance effect of nitrogen atoms and boron atoms, the HOMO and LUMO orbital electron cloud distributions can be significantly separated without the introduction of donor or acceptor groups. At the same time, the BN series of MR-TADF materials can achieve narrowband emission, which can significantly improve color purity. However, in the BN series of MR-TADF materials, due to the large overlap between dopant materials or between dopant materials and host materials, their triplet excitons are relatively stable, and the lifetime of triplet excitons is increased, resulting in a decrease in the luminous efficiency or shortened lifetime of organic electroluminescent devices. In addition, a red shift phenomenon may also occur, limiting the application of BN series TADF materials in organic electroluminescent devices.

[0065] In response to the problems of reduced luminous efficiency and shortened lifespan of BN series TADF materials, the present disclosure proposes an inventive concept of introducing functional groups that can prevent intermolecular overlap into TADF materials, and introducing silicon-containing substituents into the planar molecular skeleton doped with boron and nitrogen. The silicon-containing substituents have little effect on the HOMO orbital, LUMO orbital, triplet state (T1) and singlet state (S1) of the TADF material, that is, the introduction of silicon-containing substituents has little effect on the singlet-triplet energy level difference (ΔEst) and narrowband emission of the TADF material. However, the silicon-containing substituents can prevent overlap between dopant materials (dopant) and overlap between dopant materials and host materials (host), reduce the stability of triplet excitons to shorten the lifespan of triplet excitons, promote the RISC process, thereby enhancing the rate at which triplet excitons are converted to singlet excitons, shortening the existence time of excitons, and prolonging the lifespan while improving luminous efficiency. At the same time, the triplet state can be moved to a shorter wavelength, i.e., a blue shift is generated, thereby realizing a TADF material that provides deep blue light. In addition, as Figure 2 As shown, since the silicon-carbon bond (Si-C) is longer than the carbon-carbon bond (CC), the silicon-containing substituent can occupy a wider space, thereby giving the organic compound containing boron and nitrogen a more three-dimensional structure, so as to more significantly improve the luminous efficiency and life of the organic electroluminescent device through the more three-dimensional structure.

[0066] It should be noted that in the examples of this application, the symbols of each element are commonly used in the art. The symbol "H" represents hydrogen, including the three isotopes of hydrogen ( 1 H), deuterium ( 2 H) and tritium ( 3 H); the symbol "D" alone represents deuterium ( 2 H).

[0067] As an optional embodiment, in Formula 1, R1 to R 12 Each is independently selected from substituents containing 1 to 4 aromatic rings and / or aromatic heterocycles.

[0068] In electroluminescent devices, improving external quantum efficiency (EQE) requires careful design of device components, architecture, and electrical performance. Furthermore, efficiency is directly dependent on the intrinsic efficiency of the luminescent material used, i.e., the ratio of photons emitted by each molecule. This efficiency is typically quantified in photoluminescence (PL) experiments, also known as the photoluminescence quantum yield (PLQY).

[0069] In some embodiments, by introducing aromatic rings and / or aromatic heterocycles into the skeleton of the boron-nitrogen-containing organic compound represented by Formula 1, the dispersion of the HOMO orbital on the molecular orbital can be expanded to a certain extent, thereby improving the photoinduced quantum yield (PLQY) of the boron-nitrogen-containing organic compound, and further improving the external quantum efficiency (EQE) of the organic electroluminescent device. At the same time, the introduction of 1 to 4 aromatic rings and / or aromatic heterocycles can also improve the overall stereochemistry of the boron-nitrogen-containing organic compound, making the structure of the boron-nitrogen-containing organic compound more three-dimensional, thereby improving the luminous efficiency and life of the organic electroluminescent device.

[0070] As an optional embodiment, in Formula 1, R1 and R2 are bonded to form a 5-8 membered ring, and / or, R3 and R4 are bonded to form a 5-8 membered ring, and / or, R5 and R6 are bonded to form a 5-8 membered ring, and / or, R7 and R8 are bonded to form a 5-8 membered ring, and / or, R9 and R 10 bonded to form a 5- to 8-membered ring, and / or, R 11 and R 12 Bonded into 5- to 8-membered rings.

[0071] In some embodiments, R1 and R2 are bonded to form a 5-8 membered ring, and / or R3 and R4 are bonded to form a 5-8 membered ring, and / or R5 and R6 are bonded to form a 5-8 membered ring, and / or R7 and R8 are bonded to form a 5-8 membered ring, and / or R9 and R 10 bonded to form a 5- to 8-membered ring, and / or, R 11 and R 12 The bonds are formed into 5- to 8-membered rings. Bonding into 5- to 8-membered rings can make the structures and relative positions of these adjacent substituents more stable, and can also, to a certain extent, make the torsion angles between these adjacent substituents and the skeleton of the organic compound containing boron and nitrogen more stable, thereby avoiding changes in the torsion angles between these adjacent substituents and the skeleton, and further avoiding the instability of the organic compound containing boron and nitrogen caused by the change in the torsion angle, thereby avoiding the attenuation of the performance of the organic electroluminescent device caused by the instability of the organic compound containing boron and nitrogen. In other words, by bonding adjacent substituents into 5- to 8-membered rings, the efficiency of the organic electroluminescent device can be improved to a certain extent, the life of the organic electroluminescent device can be extended, and the defects of efficiency roll-off and shortened life of the organic electroluminescent device can be avoided.

[0072] As an optional embodiment, in Formula 1, X1, X3, X4, X5, X8, X9, X 10 、X 11 and X 12 are the same as or different from each other and are each independently selected from CD and N.

[0073] As an optional embodiment, in Formula 1, X2, X6 and X7 are the same as or different from each other, and are independently selected from CD and N.

[0074] In some embodiments of the present disclosure, in the boron-nitrogen-containing organic compound shown in general formula 1, since the phenyl group of the skeleton is connected to the electron-withdrawing functional group boron (B), the chemical reactivity of the meta-position of the electron-withdrawing functional group boron (B) in the phenyl group will be enhanced, and to a certain extent, the chemical reactivity of the ortho-position and para-position of the electron-withdrawing functional group boron (B) in the phenyl group will also be enhanced.

[0075] Since the phenyl group of the skeleton is also connected to the electron-donating functional group nitrogen (N), the meta position of the electron-withdrawing functional group boron (B) and the ortho position of the electron-donating functional group nitrogen (N) are at the same position of the phenyl group of the skeleton, that is, X1, X3, X4, X5, X8, X9, X10, X110, X120, X130, X140, X150, X160, X170, X180, X190, X200, X210, X220, X230, X240, X250, X260, X270, X280, X30 ... 10 、X 11 and X 12 The positions shown in FIG5 will cause the chemical reaction activity of these phenyl positions to become very high, causing the hydrogen at these phenyl positions to be easily detached, reducing the stability of the organic compound containing boron and nitrogen, and further reducing the life of the organic electroluminescent device. In order to avoid the reduction in the life of the organic electroluminescent device due to this reason, in some embodiments, X1, X3, X4, X5, X8, X9, X10, X11, X12, X13, X14, X15, X16, X17, X18, X19, X20, X21, X22, X23, X24, X25, X26, X27, X28, X30, X31, X32, X33, X34, X35, X36, X37, X38, X39, X40, X41, X42, X43, X44, X45, X46, X47, X48, X49, X59, X59, X60, X61, X62, X70, X71, X72, X73, X74, X75 10 、X 11 and X 12 The CH groups at the shown positions are CD groups and / or N groups, that is, the protium (H) at these positions of the phenyl group of the skeleton can be replaced by deuterium (D), or the CH at these positions can be directly replaced by nitrogen (N), thereby reducing the activity of these positions and preventing the fall-off of protium (H) on the phenyl group, so as to improve the stability of the boron-nitrogen-containing organic compound of the embodiment of the present disclosure, thereby improving the life of the organic electroluminescent device.

[0076] In addition, due to the ortho and para positions of the electron-withdrawing functional group boron (B) in the phenyl group of the skeleton and the meta position of the electron-donating functional group nitrogen (N) in the same position of the phenyl group of the skeleton, i.e., the positions shown in X2, X6 and X7 in the general formula 1, the chemical reaction activity of these positions also increases to a certain extent, causing the hydrogen at these positions of the phenyl group to also fall off more easily, reducing the stability of the organic compound containing boron and nitrogen, and thus causing the life of the organic electroluminescent device to decrease. In order to avoid causing the life of the organic electroluminescent device to decrease due to this reason, in some embodiments, the CH group at the positions shown in X2, X6 and X7 in the phenyl group of the skeleton can be a CD group and / or an N group, that is, the protium (H) at these positions of the phenyl group of the skeleton can be replaced with deuterium (D), or the CH at these positions can be directly replaced with nitrogen (N), thereby reducing the activity of these positions, preventing the falling off of protium (H) on the phenyl group, to improve the stability of the organic compound containing boron and nitrogen of the disclosed embodiments to a certain extent, and thus improving the life of the organic electroluminescent device.

[0077] As an optional embodiment, the structure of the organic compound containing boron and nitrogen is shown in Formula 2 or Formula 3:

[0078]

[0079] In general formula 2 and general formula 3, R1 to R 12 、X1~X 12 The definitions of are the same as those in Formula 1.

[0080] In some embodiments, a silicon-containing substituent as shown in Formula 2 or Formula 3 can be introduced into the boron-nitrogen-containing organic compound shown in Formula 1, and the silicon-containing substituent is connected to multiple phenyl groups, such as Figure 2 As shown, the multiple phenyl groups connected to silicon are twisted with each other, so that the structure of the silicon-containing substituent itself is more three-dimensional. When the substituent is connected to the planar molecular skeleton, the various phenyl groups in the silicon-containing substituent and the molecular skeleton will not be in the same plane, so that the molecular structure of the formed organic compound containing boron and nitrogen is more three-dimensional, so as to prevent the overlap between dopant materials (dopant) and the overlap between dopant materials and host materials (host) to a certain extent, reduce the stability of triplet excitons to shorten the lifetime of triplet excitons, promote the RISC process, thereby enhancing the rate of conversion of triplet excitons to singlet excitons, shortening the existence time of excitons, improving the luminous efficiency and extending the lifetime, and at the same time making the triplet state move to a shorter wavelength, that is, producing a blue shift, to achieve a TADF material that provides deep blue light.

[0081] At the same time, because the silicon-carbon bond (Si-C) is longer than the carbon-carbon bond (CC), the silicon-containing substituent formed by connecting silicon to multiple phenyl groups occupies a larger space and has a stronger three-dimensional structure, thereby making the structure of the organic compound containing boron and nitrogen more three-dimensional, thereby improving the ability to prevent overlap between dopant materials (dopant) and between dopant materials and host materials (host), thereby making the organic electroluminescent device have higher luminous efficiency and longer life.

[0082] As an optional embodiment, the singlet energy level (E S1 ) and triplet energy level (E T1 ) energy level difference (ΔE st ) is greater than 0eV and less than 1.0eV.

[0083] In TADF materials, the energy level difference (ΔE st ) is one of the most important physical parameters of TADF materials. The smaller energy level difference (ΔE st ) is the main characteristic of TADF materials, which greatly affects the reverse intersystem crossing (RISC) process. The smaller the energy level difference, the easier it is for triplet excitons to achieve reverse intersystem crossing (RISC) process. In other words, the energy level difference (ΔEst) is negatively correlated with the rate of reverse intersystem crossing (RISC) process of triplet excitons. The smaller the energy level difference (ΔEst), the easier it is for triplet excitons to achieve reverse intersystem crossing (RISC) process. st ) can increase the conversion efficiency of triplet excitons to singlet excitons, which is beneficial to increase the external quantum efficiency (EQE) of TADF materials.

[0084] In some embodiments of the present disclosure, the singlet energy level (E S1 ) and triplet energy level (E T1 ) energy level difference (ΔE st ) is greater than 0eV and less than 1.0eV, that is, the energy level difference (ΔE st ) as close to 0eV as possible, so that triplet excitons are more easily converted into singlet excitons, so as to achieve the purpose of improving the luminous efficiency of the organic electroluminescent device and extending the life of the organic electroluminescent device.

[0085] In some embodiments, the energy level difference (ΔE st ) is calculated based on the time-dependent density functional theory (TD-DFT), and the simulation calculations are performed using the B3LYP / 6–31G(d,p) basis set level in TD-DFT.

[0086] As an optional embodiment, the organic compound containing boron and nitrogen satisfies the following conditions:

[0087] The triplet energy level (E T1 ) is greater than or equal to 2.60 eV;

[0088] The triplet excitation wavelength (λ T1 ) is less than or equal to 480 nm; and

[0089] HOMO orbital energy level (E HOMO ) is greater than or equal to 4.60eV.

[0090] In some embodiments, the triplet energy level (E T1 ) is greater than or equal to 2.60eV, the HOMO orbital energy level (E HOMO ) is greater than or equal to 4.60eV, on the one hand, it can ensure the singlet energy level (E S1 ) and triplet energy level (E T1 ) energy level difference (ΔE st ) is smaller, and on the other hand, it can also be more effective in shortening the triplet excitation wavelength, making the triplet excitation wavelength (λ T1 ) is less than or equal to 480nm, thereby emitting deeper blue light and reducing the full width at half maximum (FWHM), and the emitted blue light has higher purity; in addition, at the same time, it can also improve the stability of organic compounds containing boron and nitrogen, improve the luminous efficiency of organic electroluminescent devices, and reduce the driving voltage of organic electroluminescent devices.

[0091] As an optional embodiment, the organic compound containing boron and nitrogen is represented by any one of Formulas 1 to 30:

[0092]

[0093]

[0094]

[0095]

[0096]

[0097] Based on time-dependent density functional theory (TD-DFT), simulation calculations were performed on the organic compounds containing boron and nitrogen in the above-mentioned embodiments at the B3LYP / 6–31G (d, p) basis set level. The performance parameters such as the triplet energy level of the organic compounds containing boron and nitrogen in the above-mentioned embodiments were obtained through simulation calculations. The structures are shown in Table 1.

[0098] Table 1 Performance parameters of organic compounds containing boron and nitrogen

[0099]

[0100]

[0101] The boron-nitrogen-containing organic compounds of the above embodiments can be synthesized and prepared using conventional methods. Hereinafter, this application also provides exemplary synthesis routes and preparation methods for some of the above-mentioned boron-nitrogen-containing organic compounds. It should be noted that the preparation methods for the above-mentioned boron-nitrogen-containing organic compounds described below are not intended to limit the characteristics of the above-mentioned heterocyclic compounds.

[0102] For example, in some embodiments, the organic compound containing boron and nitrogen as shown in Formula 3 can be synthesized using the following synthesis route as shown in Process Formula 1.

[0103]

[0104] Based on the same inventive concept, the present disclosure also provides an organic electroluminescent device, in which at least one functional layer contains the above-mentioned organic compound containing boron and nitrogen.

[0105] The organic electroluminescent device proposed in the embodiment of the present application includes the above-mentioned organic compound containing boron and nitrogen, which can make the organic electroluminescent device emit blue light with higher purity, improve the stability of the organic electroluminescent device, and have higher luminous efficiency and lifespan. To a certain extent, it overcomes the defects of severe efficiency roll-off and short device life of blue light TADF materials in related technologies, so that organic compounds containing boron and nitrogen as TADF materials can be better used in commercial applications.

[0106] In some embodiments of the present application, the above-mentioned organic compound containing boron and nitrogen can be used in a blue organic electroluminescent device, a red organic electroluminescent device, or a green organic electroluminescent device. The above-mentioned organic compound containing boron and nitrogen can be used in a single-layer organic electroluminescent device or a multi-layer organic electroluminescent device.

[0107] In some embodiments, an organic electroluminescent device includes an anode, a cathode, and at least one functional layer located between the anode and the cathode. The at least one functional layer in the organic electroluminescent device contains the aforementioned organic compound containing boron and nitrogen.

[0108] As an optional embodiment, the functional layer includes an emission layer (EML), and the emission layer contains at least one of the above-mentioned organic compounds containing boron and nitrogen.

[0109] In some embodiments of the present application, organic compounds containing boron and nitrogen can be used as the host material, dopant material, or co-doped material of the light-emitting layer. The host material can also be called the matrix material; the dopant material refers to the material used to emit light in the light-emitting layer, also known as the luminescent material; and the co-doped material refers to the material that assists the dopant material in emitting light in the light-emitting layer, also known as the sensitizing material.

[0110] As an optional embodiment, the light-emitting layer includes a host material and the above-mentioned organic compound containing boron and nitrogen, with the mass ratio of the host material to the organic compound containing boron and nitrogen being (50-90):(0-5). The organic compound containing boron and nitrogen can be used as a dopant material or as a co-doped material.

[0111] In some embodiments, the light emitting layer may include a host material and an organic compound containing boron and nitrogen as a dopant material (light emitting material).

[0112] In some embodiments, the light-emitting layer may include a host material and an organic compound containing boron and nitrogen as a co-doping material (sensitizing material). In this case, other doping materials (light-emitting materials) are also required in the light-emitting layer.

[0113] As an optional embodiment, the light-emitting layer also includes a functional material, which serves as a doping material (light-emitting material) or a co-doping material (sensitizing material), and the mass ratio of the main material, the organic compound containing boron and nitrogen, and the functional material is (50-90): (0-5): (10-40).

[0114] In some embodiments, the light-emitting layer includes a host material, an organic compound containing boron and nitrogen, and a functional material. Specifically, when the organic compound containing boron and nitrogen is used as a doping material (light-emitting material), the functional material is used as a co-doping material (sensitizing material); when the organic compound containing boron and nitrogen is used as a co-doping material (sensitizing material), the functional material is used as a doping material (light-emitting material). In other words, the light-emitting layer may include a host material, a doping material, and a co-doping material. The organic compound containing boron and nitrogen proposed in the embodiment of the present application can be used as a doping material (light-emitting material) in combination with a functional material as a co-doping material (sensitizing material). The organic compound containing boron and nitrogen proposed in the embodiment of the present application can also be used as a doping material (sensitizing material) in combination with a functional material as a doping material (light-emitting material).

[0115] In some embodiments, the light-emitting layer may include a host material, an organic compound containing boron and nitrogen as a doping material, and a fluorescent compound as a co-doping material.

[0116] In some embodiments, the light-emitting layer may include a host material, a fluorescent compound as a doping material, and an organic compound containing boron and nitrogen as a co-doping material.

[0117] In some embodiments, the light emitting layer may include a host material, an organic compound containing boron and nitrogen as a dopant material, and a phosphorescent compound as a co-doped material.

[0118] In some embodiments, the light emitting layer may include a host material, a phosphorescent compound as a dopant material, and an organic compound containing boron and nitrogen as a co-doping material.

[0119] As an optional embodiment, the functional material is selected from the compound shown in Formula 31 or Formula 32:

[0120]

[0121] As an optional implementation, Figure 1 As shown, the organic electroluminescent device includes an electron injection layer (EIL), an electron transport layer (ETL) and / or a hole blocking layer (HBL), an emitting layer (EML), an electron blocking layer (EBL) and / or a hole transport layer (HTL), and a hole injection layer (HIL) stacked in sequence. The thickness of the electron injection layer (EIL) is 0 nm to 3 nm, the thickness of the electron transport layer (ETL) is 20 nm to 40 nm, the thickness of the hole blocking layer (HBL) is 0 nm to 10 nm, the thickness of the emitting layer (EML) is 20 nm to 40 nm, the thickness of the electron blocking layer (EBL) is 0 nm to 10 nm, the thickness of the hole transport layer (HTL) is 100 nm to 200 nm, and the thickness of the hole injection layer (HIL) is 0 nm to 10 nm.

[0122] In some embodiments, when the thickness of each of the multiple functional layers of the organic electroluminescent device varies within the aforementioned thickness range, the color of the light emitted will vary within the same color range. In some embodiments, the hole blocking layer and the electron transport layer may be the same layer.

[0123] In some embodiments, the electron blocking layer can be the same layer as the hole transporting layer.

[0124] In some embodiments, as Figure 1 As shown, the organic electroluminescent device includes a cathode (Cathode), an electron injection layer (EIL), an electron transport layer (ETL), a hole blocking layer (HBL), an emitting layer (EML), an electron blocking layer (EBL), a hole transport layer (HTL), a hole injection layer (HIL) and an anode (Anode) stacked in sequence.

[0125] In some embodiments, an organic electroluminescent device may include a cathode (Cathode), an electron injection layer (EIL), an electron transport layer (ETL), an emission layer (EML), a hole transport layer (HTL), a hole injection layer (HIL), and an anode (Anode) stacked in sequence.

[0126] In some embodiments, the cathode material can be a metal material, such as any one or an alloy of two or more of aluminum, magnesium, silver, indium, tin, and titanium. The cathode material can also be a multilayer structure composed of a metal and a metal compound material, such as any one or more of lithium fluoride / aluminum, lithium oxide / aluminum, and barium fluoride / aluminum. In addition to the cathode materials listed above, the cathode material can also be a material that facilitates electron injection and a combination thereof, including known materials suitable for use as a cathode.

[0127] In some embodiments, the anode material can be a metal material, such as any one or more alloys of copper, gold, silver, iron, chromium, nickel, palladium, and platinum. The anode material can also be a metal oxide, such as any one or more of indium oxide, zinc oxide, indium tin oxide (ITO), and indium zinc oxide (IZO). The anode material can also be a self-conductive polymer, such as any one or more of polyaniline, polypyrrole, and poly(3-methylthiophene). In addition to the anode materials listed above, the anode material can also be a material that facilitates hole injection and a combination thereof, including known materials suitable for use as an anode.

[0128] In some embodiments, the electron injection layer material can be any one or more of alkali metal materials, metal materials, alkali metal compounds and metal compounds, for example, any one or more of lithium fluoride (LiF), ytterbium (Yb), magnesium (Mg) and calcium (Ca).

[0129] In some embodiments, the electron transport layer material / hole blocking layer material can be a heterocyclic aromatic compound, for example, imidazole derivatives such as benzimidazole derivatives, imidazopyridine derivatives and benzimidazolephenanthridine derivatives can be used; oxazine derivatives such as pyrimidine derivatives and triazine derivatives can also be used; compounds containing a nitrogen six-membered ring structure such as quinoline derivatives, isoquinoline derivatives and phenanthroline derivatives can also be used, including compounds having a phosphine oxide-based substituent on the heterocyclic ring; 2-(4-biphenyl)-5-(4-tert-butylphenyl)-1,3- ,4-oxadiazole (PBD), 1,3-bis[5-(p-tert-butylphenyl)-1,3,4-oxadiazole-2-yl]benzene (OXD-7), 3-(4-tert-butylphenyl)-4-phenyl-5-(4-biphenyl)-1,2,4-triazole (TAZ), 3-(4-tert-butylphenyl)-4-(4-ethylphenyl)-5-(4-biphenyl)-1,2,4-triazole (p-EtTAZ), bathophenanthroline (BPhen), bathocuproine (BCP) and 4,4'-bis(5-methylbenzoxazol-2-yl)stilbene (BzOs), etc.

[0130] In some embodiments, the hole transport layer material / electron blocking layer material can be an aromatic amine or carbazole material with hole transport properties, for example, 4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (NPB), N,N'-bis(3-methylphenyl)-N,N'-diphenyl-[1,1'-biphenyl]-4,4'-diamine (TPD), 4-phenyl-4'-(9-phenylfluorene-9-yl)triphenylamine (BAFLP), 4,4'-bis[N-(9,9-dimethylfluorene-2-yl)-N-phenylamino]biphenyl (DFLDPBi), 4,4'-di(9-carbazolyl)biphenyl (CBP) and 9-phenyl-3-[4-(10-phenyl-9-anthracenyl)phenyl]-9H-carbazole (PCzPA) can be used.

[0131] In some embodiments, the hole injection layer material can be an inorganic oxide, for example, any one or more of molybdenum oxide, titanium oxide, vanadium oxide, rhenium oxide, ruthenium oxide, chromium oxide, zirconium oxide, hafnium oxide, tantalum oxide, silver oxide, tungsten oxide and manganese oxide can be used; p-type dopants of strong electron-withdrawing systems and dopants of hole transport materials can also be used, for example, hexacyanohexaazatriphenylene, 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4TCNQ) and 1,2,3-tris[(cyano)(4-cyano-2,3,5,6-tetrafluorophenyl)methylene]cyclopropane can be used.

[0132] The organic electroluminescent device of the embodiment of the present disclosure can be prepared using conventional methods. For example, each functional layer can be prepared by vacuum evaporation. An exemplary method for preparing an organic electroluminescent device is as follows:

[0133] The anode layer on the transparent glass substrate is cleaned, dried, and placed in a vacuum deposition chamber. When the vacuum reaches the set standard, the hole injection layer, hole transport layer, electron blocking layer, luminescent layer, hole blocking layer, electron transport layer, and electron injection layer are sequentially deposited on the anode layer. Finally, the cathode layer is formed by vapor deposition. The thickness of each functional layer can be determined based on the design structure of the organic electroluminescent device. The luminescent layer includes at least a host material and a dopant material. The host material and dopant material can be mixed in a certain proportion before being deposited.

[0134] Example 1

[0135] The structure of the organic electroluminescent device prepared in Example 1 is as follows:

[0136] ITO / HIL:PD (5nm, 98:2) / HTL (150nm) / EBL (5nm) / Host:organic compound containing boron and nitrogen shown in Formula 3 (30nm, 85:15) / HBL (5nm) / ETL:LIQ (30nm, 1:1) / LIQ (1nm) / Mg:Ag (120nm, 9:1).

[0137] The organic compound containing boron and nitrogen shown in Formula 3 is used as the doping material (luminescent material) in the light-emitting layer; the compounds used as materials for each functional layer are as follows:

[0138]

[0139]

[0140] Example 2

[0141] The structure of the organic electroluminescent device prepared in Example 2 is as follows:

[0142] ITO / HIL:PD(5nm,98:2) / HTL(150nm) / EBL(5nm) / Host:Organic compound containing boron and nitrogen shown in Formula 3:Dopant(35nm,75:15:10) / HBL(5nm) / ETL:LIQ(30nm,1:1) / LIQ(1nm) / Mg:Ag(120nm,9:1).

[0143] The boron-nitrogen-containing organic compound shown in Formula 3 is used as a co-doping material (sensitizing material) in the light-emitting layer to sensitize the light-emitting material. Dopant is a fluorescent light-emitting material used as a doping material (light-emitting material). The compounds used in the functional layer materials are the same as those in Example 1, except that Dopant is as follows:

[0144]

[0145] Example 3

[0146] The structure of the organic electroluminescent device prepared in Example 3 is as follows:

[0147] ITO / HIL:PD(5nm,98:2) / HTL(150nm) / EBL(5nm) / Host:FB:organic compound containing boron and nitrogen shown in Formula 5:Dopant(35nm,75:20:5) / HBL(5nm) / ETL:LIQ(30nm,1:1) / LIQ(1nm) / Mg:Ag(120nm,9:1).

[0148] The organic compound containing boron and nitrogen shown in Formula 5 is used as the doping material (luminescent material) in the light-emitting layer, and FB is a co-doping material (sensitizing material) to sensitize the light-emitting material. The compounds used in the functional layer materials are the same as those in Example 1, except that FB is as follows:

[0149]

[0150] Example 4

[0151] The structure of the organic electroluminescent device prepared in Example 4 is as follows:

[0152] ITO / HIL:PD(5nm,98:2) / HTL(150nm) / EBL(5nm) / Host:Organic compound containing boron and nitrogen shown in Formula 3:Dopant(35nm,70:15:15) / HBL(5nm) / ETL:LIQ(30nm,1:1) / LIQ(1nm) / Mg:Ag(120nm,9:1).

[0153] The boron-nitrogen-containing organic compound shown in Formula 3 is used as a co-dopant material (sensitizing material) in the light-emitting layer to sensitize the light-emitting material. Dopant is a phosphorescent compound used as a doping material (light-emitting material). The compounds used in the functional layer materials are the same as those in Example 1, except that Dopant is as follows:

[0154]

[0155] Example 5

[0156] The structure of the organic electroluminescent device prepared in Example 5 is as follows:

[0157] ITO / HIL:PD(5nm,98:2) / HTL(150nm) / EBL(5nm) / Host:PhB:organic compound containing boron and nitrogen shown in Formula 3 (400nm,75:15:10) / HBL(5nm) / ETL:LIQ(30nm,1:1) / LIQ(1nm) / Mg:Ag(120nm,9:1).

[0158] The organic compound containing boron and nitrogen shown in Formula 3 is used as the doping material (luminescent material) in the light-emitting layer, and PhB is a phosphorescent compound used as a co-doping material (sensitizing material) to sensitize the light-emitting material. The compounds used in the functional layer materials are the same as those in Example 1, except that PhB is as follows:

[0159]

[0160] Comparative Example:

[0161] The structure of the organic electroluminescent device of the comparative example is as follows:

[0162] ITO / HIL:PD(5nm,98:2) / HTL(150nm) / EBL(5nm) / Host:PtON7-dtb(300nm,75:25) / HBL(5nm) / ETL:LIQ(30nm,1:1) / LIQ(1nm) / Mg:Ag(120nm,9:1).

[0163] The compounds used in the functional layer materials are the same as those in Example 1, except that PtON7-dtb is as follows:

[0164]

[0165] In some embodiments provided in the present disclosure, the performance parameters of the organic electroluminescent device are shown in Table 2.

[0166] Table 2 Performance parameters of organic electroluminescent devices

[0167] Device Voltage* Luminous efficiency* CIEX CIE Service life* Comparative Example 4.9(V) 8.5 (cd / A) 0.134 0.067 13.4 (LT95@1000nit) Example 1 104％ 110％ 0.138 0.067 105％ Example 2 102％ 108％ 0.136 0.065 105％ Example 3 104％ 120％ 0.136 0.068 118％ Example 4 101％ 150％ 0.134 0.067 120％ Example 5 99％ 118％ 0.138 0.064 157％

[0168] *The voltage, luminous efficiency and service life in the examples are calculated based on the comparative example.

[0169] Based on the same inventive concept, the present disclosure also proposes a lighting or display device, which includes the above-mentioned organic electroluminescent device.

[0170] Since the lighting or display device provided by the present invention includes the organic electroluminescent device of the above technical solution, the lighting or display device provided by the present invention has all the beneficial effects of the above organic electroluminescent device, which will not be described in detail here.

[0171] In the description of this specification, the reference terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present disclosure. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification.

[0172] In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the fact that ordinary technicians in this field can implement them. When the combination of technical solutions is mutually contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by this disclosure.

[0173] Although the embodiments of the present disclosure have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and alterations may be made to the embodiments without departing from the principles and spirit of the present disclosure, the scope of which is defined by the claims and their equivalents.

Claims

1. An organic electroluminescent device, characterized in that: The organic electroluminescent device includes at least one functional layer, the functional layer includes a light-emitting layer, the light-emitting layer includes a host material, an organic compound containing boron and nitrogen, and a functional material, the host material, the organic compound containing boron and nitrogen, and the functional material are respectively represented by Formula 33, Formula 3, and Formula 32, or the host material, the organic compound containing boron and nitrogen, and the functional material are respectively represented by Formula 33, Formula 5, and Formula 31.

2. The organic electroluminescent device according to claim 1, wherein The functional material is used as a doping material or a co-doping material, and the mass ratio of the main material, the organic compound containing boron and nitrogen, and the functional material is (50-90):(0-5):(10-40).

3. The organic electroluminescent device according to claim 1 or 2, wherein: The organic electroluminescent device includes an electron injection layer, an electron transport layer and / or a hole blocking layer, the light-emitting layer, the electron blocking layer and / or the hole transport layer, and a hole injection layer stacked in sequence. The thickness of the electron injection layer is 0nm to 3nm, the thickness of the electron transport layer is 20nm to 40nm, the thickness of the hole blocking layer is 0nm to 10nm, the thickness of the light-emitting layer is 20nm to 40nm, the thickness of the electron blocking layer is 0nm to 10nm, the thickness of the hole transport layer is 100nm to 200nm, and the thickness of the hole injection layer is 0nm to 10nm.

4. A lighting or display device, characterized in that: The organic electroluminescent device comprises the organic electroluminescent device according to any one of claims 1 to 3.

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