A boron-nitrogen compound, a preparation method and application thereof

Abstract

The present application provides a boron-nitrogen compound, a preparation method and application thereof, the boron-nitrogen compound has a narrow spectrum, and is used as a narrow spectrum light emitting material to prepare a light emitting layer of an organic electroluminescent device, so that the organic electroluminescent device prepared by the boron-nitrogen compound realizes narrow spectrum TADF emission, and makes the electroluminescent external quantum efficiency of the device as high as more than 35%.

Description

Technical Field

[0001] This invention belongs to the field of organic electroluminescence technology, and relates to a boron nitrogen compound, its preparation method and application. Background Technology

[0002] Organic optoelectronic materials are a class of organic materials that possess properties such as the generation, conversion, and transmission of photons and electrons. Currently, the controllable optoelectronic properties of organic optoelectronic materials have been applied to organic light-emitting diodes (OLEDs), organic photovoltaics (OPVs), organic field-effect transistors (OFETs), and even organic lasers. In recent years, OLEDs have become a very popular new type of flat panel display product both domestically and internationally. OLED displays feature self-emissive characteristics, wide viewing angle, short response time, high luminous efficiency, wide color gamut, low operating voltage, thin panels, the ability to manufacture large-size flexible panels, and low cost, earning them the reputation as the star flat panel display product of the 21st century.

[0003] The history of organic electroluminescence can be traced back to the report by Bernanose et al. in 1953 (Holst GA, Kster T, Voges E, et al. FLOX—an oxygen-flux-measuring system using a phase-modulation method to evaluate the oxygen-dependent fluorescence lifetime, ScienceDirect. Sensors and Actuators B: Chemical, 1995, 29, 213.). About 10 years later, in 1963, Pope et al. of New York University observed the fluorescence emission of anthracene by applying a voltage to anthracene crystals (M. Pope, H. Kallmann and P. Magnante, Electroluminescence in Organic Crystals, J. Chem. Phys., 1963, 38, 2042). In 1987, CWTang et al. of Kodak Corporation in the United States used ultrathin film technology, employing aromatic amines with good hole transport performance as the hole transport layer, an aluminum complex of 8-hydroxyquinoline as the light-emitting layer, and indium tin oxide (ITO) thin film and a metal alloy as the anode and cathode, respectively, to fabricate a light-emitting device. This device achieved a brightness of 1000 cd / m² at a driving voltage of 10V.2 The green light emission of the device, with an efficiency of 1.5 lm / W (CWTang and S.A. Van Slyke, Organic electroluminescent diodes, Appl. Phys. Lett., 1987, 51, 913), was a breakthrough that led to the rapid and in-depth development of organic electroluminescence research worldwide. In 1990, Burroughes et al. of Cambridge University proposed the first light-emitting diode based on polymer (PPV). This showed that PPV, in monolayer devices, can serve as a highly fluorescent emitting material with high luminous efficiency (Burroughes J He et al., Light-emitting diodes based on conjugated polymers, Nature, 1990, 347, 539). In 1998, Baldo and Forrest et al. from Princeton University reported the first phosphorescent device based on electroluminescence, which in principle could have 100% internal quantum yield (MA Baldo, DFO' Brinetal., Highly efficient phosphorescent emission from organic electroluminescent devices, Nature, 1998, 395, 151). However, on the one hand, phosphorescent materials generally use precious metals such as iridium and platinum, which are expensive. On the other hand, deep blue phosphorescent materials still have chemical instability and large efficiency roll-off problems at high current densities. Therefore, it is extremely important to develop an OLED device that can achieve high-efficiency light emission using inexpensive and stable small organic molecule materials.

[0004] In 2012, the Adachi research group at Kyushu University reported a highly efficient all-fluorescent OLED device based on the thermally activated delayed fluorescence (TADF) mechanism (Uoyama H, Goushi K, Shizu K, et al. Highly efficient organic light-emitting diodes from delayed fluorescence, Nature, 2012, 492(7428):234-238.). When the energy difference between the S1 and T1 levels of a molecule is sufficiently small, the triplet exciton can absorb thermal energy, return to the singlet state through a RISC process, and then emit fluorescence. Theoretically, the internal quantum efficiency (IQE) of this device can reach 100%, and the external quantum efficiency (EQE) can even reach 30%, comparable to the level of phosphorescent devices. As a next-generation light-emitting material, research on TADF materials is booming.

[0005] TADF molecules are mainly used as guest materials to dope in wide-bandgap host materials to achieve high-efficiency thermally activated delayed fluorescence (Q. Zhang, J. Li, K. Shizu, et al. Design of Efficient Thermally Activated Delayed Fluorescence Materials for Pure Blue Organic Light Emitting Diodes, J. Am. Chem. Soc. 2012, 134, 14706; H. Uoyama, K. Goushi, K. Shizu, H. Nomura, C. Adachi, Highly efficient organic light-emitting diodes from delayed fluorescence, Nature, 2012, 492, 234; T. Nishimoto, T. Yasuda, et al. Asix-carbazole-decorated cyclophosphazene as a host with high triplet energy to realize efficient delayed-fluorescence OLEDs, Mater. Horiz. 2014, 1, 264). Unlike traditional fluorescent molecules that emit light from localized (LE) states, TADF emission primarily originates from transitions between ICT states. Therefore, it is easily affected by vibrational and rotational motions between donor and acceptor states, resulting in a broader spectrum. While this broader spectrum is advantageous for lighting applications, it cannot meet the high color purity requirements of the display industry. Since OLEDs are primarily used for displays, a narrow spectral design (i.e., a smaller half-width at half-maximum, FWHM) for TADF materials is essential. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the present invention aims to provide a boron-nitrogen compound, its preparation method, and its applications. The compound provided by this invention aims to overcome the defects of TADF luminescent molecules, providing a narrow-spectrum luminescent material for preparing the luminescent layer of organic electroluminescent devices, thereby enabling narrow-spectrum TADF emission in organic electroluminescent devices.

[0007] To achieve this objective, the present invention employs the following technical solution:

[0008] On one hand, the present invention provides a boron-nitrogen compound having the structure shown in Formula I:

[0009]

[0010] W, X, Y, and Z represent CH or N, and one of W, X, Y, and Z is N, while the rest are CH;

[0011] R1 and R2 are independently selected from H, D (deuterium), fluorine, CN, C1-C20 alkyl, C1-C20 alkoxy, C3-C10 cycloalkyl, C6-C14 aryl, and are influenced by one or more Rs. a Substituted C6-C18 aryl, 5- to 18-heteroaryl, and substituted with one or more R a Substituted 5- to 18-membered heteroaryl, diphenylamino, or substituted with one or more R a Substituted diphenylamine group;

[0012] R a Each time it appears independently as D (deuterium), fluorine, CN, C1-C12 alkyl, C1-C12 alkoxy, C3-C12 cycloalkyl, C6-C14 aryl, or with one or more Rs. b Substituted C6-C14 aryl, 5- to 18-membered heteroaryl, and substituted with one or more R b Substituted 5- to 18-membered heteroaryl, diphenylamino, or substituted with one or more R b Substituted diphenylamine group;

[0013] R b Each time it appears independently as D (deuterium), fluorine, CN, C1-C12 alkyl, C1-C12 alkoxy, C3-C10 cycloalkyl, C6-C14 aryl, or with one or more Rs. c Substituted C6-C14 aryl, 5- to 18-membered heteroaryl, and substituted with one or more R c Substituted 5- to 18-membered heteroaryl, diphenylamino, or substituted with one or more R c Substituted diphenylamine group;

[0014] R c Each time it appears independently as D (deuterium), fluorine, CN, C1-C12 alkyl, C1-C12 alkoxy, C3-C10 cycloalkyl, C6-C14 aryl, or with one or more Rs. d Substituted C6-C14 aryl, 5- to 18-membered heteroaryl, and substituted with one or more R d Substituted 5- to 18-membered heteroaryl, diphenylamino, or substituted with one or more R d Substituted diphenylamine group;

[0015] R d Each time it appears, it is independently D (deuterium), fluorine, C1-C12 alkyl, C1-C12 alkoxy, C3-C10 cycloalkyl, C6-C14 aryl, or is associated with one or more R groups. e Substituted C6-C14 aryl groups;

[0016] R e Each time it appears, it is independently D (deuterium), fluorine, C1-C12 alkyl, C1-C12 alkoxy, C3-C10 cycloalkyl, or C6-C14 aryl;

[0017] The alkyl, alkoxy, cycloalkyl, aryl, and heteroaryl groups are optionally substituted with one or more substituents selected from the following: halogen, -CN, C1-C12 alkyl, C1-C12 alkoxy, C1-C12 haloalkyl, C2-C6 alkenyl, C3-C10 cycloalkyl, C6-C14 aryl, and 5- to 18-membered heteroaryl.

[0018] In this invention, the phrase "alkyl, alkoxy, cycloalkyl, aryl, heteroaryl optionally substituted with one or more substituents selected from the following" means that the alkyl, alkoxy, cycloalkyl, aryl, heteroaryl can be unsubstituted alkyl, alkoxy, cycloalkyl, aryl, or heteroaryl, or can be substituted alkyl, substituted alkoxy, substituted cycloalkyl, substituted aryl, or substituted heteroaryl. When the group is substituted, the substituent is selected from one or more of the listed groups (halogen, -CN, C1-C12 alkyl, C1-C12 alkoxy, C1-C12 haloalkyl, C2-C6 alkenyl, C3-C10 cycloalkyl, C6-C14 aryl, and 5- to 18-membered heteroaryl).

[0019] In one embodiment, the boron nitrogen compound is a compound represented by formula I-1, I-2, I-3, or I-4:

[0020]

[0021] Where R 1 and R 2 The limitations are the same as in Equation I.

[0022] In this invention, when R in formulas I-1, I-2, I-3 and I-4 1 Same, R 2 Similarly, the compounds shown in Formulas I-1, I-2, I-3, and I-4 are four isomer molecules, and the difference between the highest and lowest values ​​of their emission peaks is 8 (±2) nm, that is, when R is selected... 1 and R 2 With the addition of substituents, the emission peak position of the molecule can be tuned in the 6-10 nm range using four isomers.

[0023] In one implementation, the R 1 and R 2 Independently, it is H, D (deuterium), fluorine, C1-C12 alkyl, C1-C 12Alkoxy, C3-C 10 cycloalkyl, phenyl, with at least one C1-C 12 Alkyl-substituted aryl group, with at least one C1-C 12 Alkoxy-substituted aryl, phenyl-C1~C 12 Alkyl, diphenylamino, with at least one C1-C 12 Alkyl-substituted diphenylamino group, carbazole group, or group with at least one C1-C 12 Alkyl-substituted carbazole group.

[0024] In one implementation, the R a Each time it appears, it is independently D (deuterium), fluorine, or C1 to C2. 12 Alkyl, C1-C 12 Alkoxy, C3-C 10 cycloalkyl, with at least one C1-C 12 Alkyl-substituted phenyl, with at least one C1-C 12 Alkoxy-substituted phenyl, phenyl-C1~C 12 Alkyl, diphenylamino, with at least one C1-C 12 Alkyl-substituted diphenylamino group, carbazole group, or group with at least one C1-C 12 Alkyl-substituted carbazole group.

[0025] In one implementation, the R b Each time it appears, it is independently D (deuterium), fluorine, or C1 to C2. 12 Alkyl, C1-C 12 Alkoxy, C3-C 10 cycloalkyl, with at least one C1-C 12 Alkyl-substituted phenyl, with at least one C1-C 12 Alkoxy-substituted phenyl, phenyl-C1~C 12 Alkyl, diphenylamino, with at least one C1-C 12 Alkyl-substituted diphenylamino group, carbazole group, or group with at least one C1-C 12 Alkyl-substituted carbazole group.

[0026] In one implementation, the R c Each time it appears, it is independently D (deuterium), fluorine, or C1 to C2. 12 Alkyl, C1-C 12 Alkoxy, C3-C 10 cycloalkyl, with at least one C1-C 12 Alkyl-substituted phenyl, with at least one C1-C 12 Alkoxy-substituted phenyl, phenyl-C1~C 12 Alkyl, diphenylamino, with at least one C1-C 12Alkyl-substituted diphenylamino group, carbazole group, or group with at least one C1-C 12 Alkyl-substituted carbazole group.

[0027] In one implementation, the R d Each time it appears, it is independently D (deuterium), fluorine, or C1 to C2. 12 Alkyl, C1-C 12 Alkoxy, C3-C 10 cycloalkyl, with at least one C1-C 12 Alkyl-substituted phenyl, with at least one C1-C 12 Alkoxy-substituted phenyl, carbazole, or alkyl-substituted phenyl groups with at least one C1-C bond 12 Alkyl-substituted carbazole group.

[0028] In one implementation, the R 1 and R 2 Independently, H, D (deuterium), fluorine, methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, hexyl, octyl, decyl, Methoxy, ethoxy, butoxy, hexoxy Cyclohexyl, adamantyl, phenyl, 4-methyl-phenyl, 4-ethyl-phenyl, 4-propyl-phenyl, 4-isopropylphenyl, 4-n-butylphenyl The wavy lines represent the connection sites of the functional groups.

[0029] In some preferred embodiments, the R 1 and R 2 Independently H, methyl, Phenyl, The wavy lines represent the connection sites of the functional groups.

[0030] In some preferred embodiments, the R 1 and R 2 Same, selected from H, methyl, Phenyl, Any one of them;

[0031] Where R g H, methyl, isopropyl, tert-butyl or

[0032] In some embodiments of the present invention, the boron nitrogen compound is any one of the following compounds:

[0033]

[0034]

[0035]

[0036] On the other hand, the present invention provides a method for preparing the boron nitrogen compound as described above, the method comprising the following steps:

[0037] (1) Compound BN-Mn reacts with pinacol borate ester to give compound BN-Mn-Bpin, as shown in the following reaction formula:

[0038]

[0039] (2) Compound BN-Mn-Bpin undergoes a coupling reaction with R-Br to give compound BN-M-Ni, as shown in the following reaction formula:

[0040]

[0041] Where R is The wavy lines represent the connection sites of the functional groups;

[0042] (3) Compound BN-M-Ni undergoes a cyclization reaction in the presence of ferric chloride to give the boron-nitrogen compound shown in Formula I, as follows:

[0043]

[0044] Preferably, the molar ratio of compound BN-Mn to pinacol diboronic acid ester in step (1) is 1:1 to 10, for example, 1:1, 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9 or 1:10.

[0045] Preferably, the reaction in step (1) is carried out in the presence of a catalyst, which is a methoxy(cyclooctadiene)iridium(I) dimer and 4,4'-di-tert-butyl-2,2'-bipyridine.

[0046] Preferably, the molar ratio of the catalyst methoxy(cyclooctadiene)iridium(I) dimer, 4,4'-di-tert-butyl-2,2'-bipyridine, and compound BN-Mn is 0.1%–10%:0.2%–20%:1. For example, the methoxy(cyclooctadiene)iridium(I) dimer is 0.1%, 1%, 2%, 4%, 5%, 7%, 9%, or 10% of the molar amount of compound BN-Mn, and the 4,4'-di-tert-butyl-2,2'-bipyridine is 0.2%, 1%, 2%, 4%, 5%, 7%, 10%, 13%, 15%, 18%, or 20% of the molar amount of compound BN-Mn.

[0047] Preferably, the solvent for the reaction in step (1) is tetrahydrofuran;

[0048] Preferably, the reaction temperature in step (1) is 60 to 100°C (e.g., 60°C, 65°C, 70°C, 75°C, 80°C, 90°C or 100°C), and the time is 6 to 24 hours (e.g., 6 hours, 8 hours, 10 hours, 12 hours, 15 hours, 18 hours, 20 hours or 24 hours).

[0049] Preferably, the molar ratio of compound BN-Mn-Bpin to compound R-Br in step (2) is 1:0.8 to 2, for example, 1:0.8, 1:1, 1:2, 1:4, 1:5, 1:7, 1:9 or 1:2.

[0050] Preferably, the reaction in step (2) is carried out in the presence of a weakly alkaline substance.

[0051] Preferably, the weakly alkaline substance is potassium carbonate.

[0052] Preferably, step (2) is carried out in the presence of a catalyst, wherein the catalyst is tetra(triphenylphosphine)palladium.

[0053] Preferably, the amount of catalyst used in step (2) is 0.1%-15% of the mass of compound BN-Mn-Bpin, for example, 0.1%, 0.5%, 1%, 3%, 5%, 7%, 10%, 12% or 15%.

[0054] Preferably, the solvent for the reaction in step (2) is tetrahydrofuran.

[0055] Preferably, the reaction in step (2) is carried out under reflux.

[0056] Preferably, the reaction time in step (2) is 5-24 hours, for example 5 hours, 7 hours, 10 hours, 12 hours, 15 hours, 18 hours, 20 hours, 22 hours or 24 hours.

[0057] Preferably, the amount of ferric chloride used in step (3) is 10 to 50 times the amount of compound BN-M-Ni, for example, 10 times, 12 times, 15 times, 20 times, 23 times, 25 times, 28 times, 30 times, 35 times, 38 times, 40 times, 45 times, 48 ​​times or 50 times.

[0058] Preferably, the solvent for the cyclization reaction in step (3) is dichloromethane.

[0059] Preferably, the cyclization reaction in step (3) is carried out at room temperature.

[0060] Preferably, the time for the cyclization reaction in step (3) is 1-8 hours, for example 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, 7 hours or 8 hours.

[0061] Preferably, the reactions described in steps (2) and (3) are carried out under nitrogen protection.

[0062] On the other hand, the present invention provides an organic electroluminescent material, wherein the organic electroluminescent material comprises the boron nitrogen compound as described above.

[0063] On the other hand, the present invention provides an organic electroluminescent device comprising an anode and a cathode and an organic thin film layer disposed between the anode and the cathode, the organic thin film layer comprising a boron nitrogen compound as described above.

[0064] Preferably, the organic thin film layer includes a light-emitting layer, an optional hole injection layer, an optional hole transport layer, an optional electron transport layer, and an optional electron injection layer, wherein at least one of the light-emitting layer, electron injection layer, electron transport layer, hole transport layer, and hole injection layer comprises a boron-nitrogen compound as described above.

[0065] In this invention, the boron-nitrogen compound having the structure shown in Formula I can be used as a functional material in at least one of the light-emitting layer, electron injection layer, electron transport layer, hole transport layer, and hole injection layer of an organic electroluminescent device.

[0066] In one embodiment, the organic electroluminescent device of the present invention may further include an optional hole blocking layer, an optional electron blocking layer, and an optional capping layer, etc.

[0067] In one embodiment, the organic electroluminescent device has, for example, Figure 1 The structure shown is as follows: 1 is the ITO anode, 2 is the hole injection layer, 3 is the hole transport layer, 4 is the light-emitting layer, 5 is the electron transport layer, 6 is the electron injection layer, and 7 is the metal cathode.

[0068] In one embodiment, the boron nitride compound having the structure shown in Formula I is used to prepare the light-emitting layer in an organic electroluminescent device.

[0069] In one embodiment, the organic electroluminescent device further includes a substrate, and an anode layer, an organic light-emitting functional layer, and a cathode layer sequentially formed on the substrate; the organic light-emitting functional layer includes a light-emitting layer containing the boron nitrogen compound as described above, and may also include any one or a combination of multiple of a hole injection layer, a hole transport layer, an electron blocking layer, a hole blocking layer, an electron transport layer, and an electron injection layer.

[0070] On the other hand, the present invention provides an organic electroluminescent composition comprising, as described above, a boron nitride compound as a dopant and a host material;

[0071] Preferably, the host material is a material having electron transport capability and / or hole transport capability and whose triplet excited state energy is equal to or higher than the triplet excited state energy of the doped material.

[0072] In one embodiment of the present invention, the host material in the organic electroluminescent composition is a carbazole derivative and / or a carbline derivative having a structure as shown in any one of formulas (H-1) to (H-6):

[0073]

[0074]

[0075] Where X1, Y1, and Z1 are CH or N, and at most one of X1, Y1, and Z1 is N;

[0076] Where R 1H and R 2H Independently, it can be any of the following groups:

[0077]

[0078] Where X1, Y1, and Z1 are CH or N, and at most one of X1, Y1, and Z1 is N;

[0079] Where R aH and R bH Independent of H, C1-C 20 Alkyl, C1-C 20 Alkoxy, C6-C 20 Aryl, C1-C 20 Alkyl-substituted C6-C 20 Aryl or C1-C 20 Alkoxy-substituted C6-C 20 Aryl group, * indicates the linking site of the group.

[0080] In one embodiment of the present invention, the organic electroluminescent composition preferably contains 0.3-30.0 wt% (by weight) of a boron nitride compound with the structure shown in Formula I as described above as a dopant material, and the remaining 99.7-70.0 wt% is a host material composed of 1-2 compounds having the structure of Formula (H-1) to Formula (H-6).

[0081] In one embodiment of the present invention, the main material contains two compounds having structures of formula (H-1) to (H-6), and the weight ratio of the two compounds is 1:5 to 5:1, for example 1:5, 1:4, 1:3, 1:2, 1:1, 2:1, 3:1, 4:1, 5:1, etc.

[0082] In one embodiment of the present invention, the host material in the organic electroluminescent composition is one or two of compounds H1-1 to H1-427.

[0083] In one embodiment of the present invention, the organic electroluminescent composition contains 0.3-30.0 wt% (by weight) of a boron nitrogen compound with the structure shown in Formula I as described above, and the remaining 99.7-70.0 wt% is one or two compounds selected from H1-1 to H1-427.

[0084] In a preferred embodiment of the present invention, the organic electroluminescent composition contains two compounds selected from H1-1 to H1-427 as the main material, and the weight ratio of the two compounds is 1:5 to 5:1, for example, 1:5, 1:4, 1:3, 1:2, 1:1, 2:1, 3:1, 4:1, 5:1, etc.

[0085]

[0086]

[0087]

[0088]

[0089]

[0090]

[0091]

[0092]

[0093]

[0094]

[0095]

[0096]

[0097]

[0098]

[0099]

[0100]

[0101]

[0102]

[0103] In one embodiment of the present invention, the doping material in the organic electroluminescent composition is any one of the boron nitrogen compounds with the structure shown in Formula I (content of 0.3wt-30.0wt%); the host material (content of 99.7wt-70.0wt%) is composed of any one of the compounds shown in Formula Trz1-A, Trz2-A, Trz3-A, Trz4-A, Trz5-A or Trz6-A and any one of the compounds having the structure shown in Formulas H-1 to H-6.

[0104] In a preferred embodiment, the weight ratio of the compounds shown in Trz1-A, Trz2-A, Trz3-A, Trz4-A, Trz5-A or Trz6-A to the compounds shown in H-1, H-2, H-3, H-4, H-5 or H-6 in the main material is from 1:5 to 5:1, for example, 1:5, 1:4, 1:3, 1:2, 1:1, 2:1, 3:1, 4:1, 5:1, etc.

[0105]

[0106] Where R 1a R 1b R 2a R 2b R 3a and R 3b One or two of them are independent as R Tz The remaining elements are, independently and identically, hydrogen, deuterium, C1-C8 alkyl, C1-C8 alkoxy, or C6-C4. 18 Aryl, C1-C8 alkyl substituted C6-C 18 Aryl or C1-C8 alkoxy-substituted C6-C 18 aryl; R Tz It can be any of the substituents shown in the following formula:

[0107]

[0108]

[0109] The asterisk represents the linking site of the functional group.

[0110] In one embodiment of the present invention, the doping material in the organic electroluminescent composition is any one of the boron nitrogen compounds with the structure shown in Formula I as described above (content of 0.3wt-30.0wt%); the host material (content of 99.7wt-70.0wt%) is composed of any one of the compounds shown in Formula TRZ-1 to TRZ-80 and any one of the carbazole or carboline derivatives shown in Formula H1-1 to H1-427.

[0111] In a preferred embodiment, the weight ratio between the compound represented by formula TRZ-1 to TRZ-80 and the carbazole or carbline derivative in the main material is 1:5 to 5:1, for example: 1:20, 1:10, 1:5, 1:4, 1:3, 1:2, 1:1, 2:1, 3:1, 4:1, 5:1, 10:1, 20:1, etc.

[0112]

[0113]

[0114]

[0115]

[0116] On the other hand, the present invention provides an organic electroluminescent material comprising the organic electroluminescent composition as described above.

[0117] On the other hand, the present invention provides an organic electroluminescent device comprising an anode and a cathode and an organic thin film layer disposed between the anode and the cathode, the organic thin film layer comprising the organic electroluminescent composition as described above.

[0118] Preferably, the organic thin film layer includes a light-emitting layer, an optional hole injection layer, an optional hole transport layer, an optional electron transport layer, and an optional electron injection layer, wherein at least one of the light-emitting layer, electron injection layer, electron transport layer, hole transport layer, and hole injection layer comprises the organic electroluminescent composition as described above.

[0119] In this invention, the organic electroluminescent composition can be used as a functional material in at least one of the following layers of an organic electroluminescent device: the light-emitting layer, the electron injection layer, the electron transport layer, the hole transport layer, and the hole injection layer.

[0120] In one embodiment of the present invention, the material of the light-emitting layer in the organic electroluminescent device comprises the organic electroluminescent composition as described above.

[0121] In one embodiment of the present invention, the organic electroluminescent composition is a light-emitting layer, and the light-emitting principle of the light-emitting layer is based on energy transfer from the host material to any compound shown in Formula I or carrier capture of the light-emitting material itself.

[0122] In one embodiment of the present invention, the organic electroluminescent composition is a light-emitting layer; the host material in the organic electroluminescent composition may be a carbazole derivative and / or a carbline derivative as shown in formulas (H-1) to (H-6). In a preferred embodiment, the organic electroluminescent composition contains 0.3-30.0 wt% of any compound shown in formula I, and the remaining 99.7-70.0 wt% is a host composed of 1-2 compounds having the structure of formulas (H-1) to (H-6). For example, when the host contains two compounds having the structure of formulas (H-1) to (H-6), the weight ratio of the two compounds is 1:5 to 5:1.

[0123] In one embodiment of the present invention, the organic electroluminescent composition is a light-emitting layer; the main material in the composition is one or two compounds selected from H1-1 to H1-427. In a preferred embodiment, the organic electroluminescent composition contains 0.3-30.0 wt% of any compound represented by Formula I or Formula II, and the remaining 99.7-70.0 wt% is one or two compounds selected from H1-1 to H1-427. For example, when the composition contains two compounds selected from H1-1 to H1-427, the weight ratio of the two compounds is 1:5 to 5:1.

[0124] In one embodiment of the present invention, the organic electroluminescent composition is a light-emitting layer; the doping material in the organic electroluminescent composition is any compound of formula I (content of 0.3wt-30.0wt%); the host material (content of 99.7wt-70.0wt%) is composed of any one of compounds of formula Trz1-A, Trz2-A, Trz3-A, Trz4-A, Trz5-A or Trz6-A and any one of compounds of formulas H-1 to H-6. For example, in the host material, the weight ratio between compounds of formula Trz1-A, Trz2-A, Trz3-A, Trz4-A, Trz5-A or Trz6-A and compounds of formulas H-1, H-2, H-3, H-4, H-5 or H-6 is 1:20 to 20:1.

[0125] In one embodiment of the present invention, the organic electroluminescent composition is a light-emitting layer; the dopant material in the organic electroluminescent composition is any compound shown in Formula I (content of 0.3wt-30.0wt%); the host material (content of 99.7wt-70.0wt%) is composed of any one of the 1,3,5-triazine derivatives shown in Formula TRZ-1 to TRZ-80 and any one of the carbazole or carboline derivatives shown in Formula H1-1 to H1-427. For example, in the host material, the weight ratio between the 1,3,5-triazine derivative and the carbazole or carboline derivative is 1:20 to 20:1.

[0126] In one embodiment of the present invention, the organic electroluminescent composition is a light-emitting layer; the doping material in the organic electroluminescent composition is any one of the compounds shown in formula BN1 to BN48 (content of 0.3wt-30.0wt%); the host material (content of 99.7wt-70.0wt%) is composed of any one of the compounds of formula Trz1-A, Trz2-A, Trz3-A, Trz4-A, Trz5-A, and Trz6-A and any one of the carbazole or carboline derivatives shown in formulas H1-1 to H1-427. For example, in the host material, the weight ratio between the compounds of formula Trz1-A, Trz2-A, Trz3-A, Trz4-A, Trz5-A, and Trz6-A and the carbazole or carboline derivatives shown in formulas H1-1 to H1-427 is 1:20 to 20:1.

[0127] In one embodiment of the present invention, the organic electroluminescent device further includes a substrate, and an anode layer, an organic light-emitting functional layer, and a cathode layer sequentially formed on the substrate; the organic light-emitting functional layer includes a light-emitting layer containing the organic electroluminescent composition as described above, and may also include any one or a combination of at least two of a hole injection layer, a hole transport layer, an electron blocking layer, a hole blocking layer, an electron transport layer, and an electron injection layer.

[0128] On the other hand, the present invention provides an application of the described organic electroluminescent device in an organic electroluminescent display or an organic electroluminescent lighting source.

[0129] Terminology Explanation

[0130] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0131] As used herein, the terms “containing” or “including (comprise)” can be open-ended, semi-closed, or closed. In other words, the terms also include “consistently made of” or “composed of”.

[0132] Group definition

[0133] In this specification, groups and their substituents may be selected by those skilled in the art to provide stable structural moieties and compounds. When a substituent is described by a conventional chemical formula written from left to right, the substituent also includes chemically equivalent substituents obtained when the structural formula is written from right to left.

[0134] The chapter headings used in this specification are for organizational purposes only and should not be construed as limiting the subject matter. All references or portions thereof cited in this invention, including but not limited to patents, patent applications, articles, books, user manuals, and papers, are incorporated herein by reference in their entirety.

[0135] Unless otherwise specified, all technical and scientific terms used herein have the standard meaning in the field to which the claimed subject matter pertains. Where multiple definitions exist for a term, the definition herein shall prevail.

[0136] It should be understood that the singular forms used in this invention, such as "a," include plural references unless otherwise specified. Furthermore, the term "comprising" is an open-ended limitation, not a closed one; that is, it includes the contents specified in this invention but does not exclude other aspects.

[0137] Unless otherwise stated, this invention employs traditional methods of mass spectrometry and elemental analysis, and the steps and conditions can be referred to conventional operating procedures and conditions in the field.

[0138] Unless otherwise specified, this invention employs standard nomenclature and standard laboratory procedures and techniques of analytical chemistry, organic synthetic chemistry, and optics. In some cases, standard techniques are used for chemical synthesis, chemical analysis, and performance testing of light-emitting devices.

[0139] The compounds of the present invention may contain atomic isotopes in non-natural proportions on one or more atoms constituting the compound. For example, the compounds may be labeled with radioactive isotopes, such as deuterium (₂H). All variations in the isotopic composition of the compounds of the present invention, regardless of radioactivity, are included within the scope of the present invention.

[0140] In this invention, unless otherwise specified, the number of "substitutes" can be one or more; when there are multiples, it means two or more, for example, two, three, or four. In this invention, "one or more" can also be equivalent to "at least one" or "one or at least two," and when the number of "substitutes" is multiple, the "substitutes" can be the same or different. In this invention, unless otherwise specified, the position of the "substitute" can be arbitrary.

[0141] In this invention, as a group or part of other groups (e.g., in halogen-substituted alkyl groups), the term "alkyl" means a saturated aliphatic hydrocarbon group comprising branched and straight chains having a specified number of carbon atoms. For example, C1-C1... 20 Alkyl groups include straight-chain or branched alkyl groups having 1 to 20 carbon atoms. As defined in "C1-C6 alkyl," it includes groups having 1, 2, 3, 4, 5, or 6 carbon atoms in a straight-chain or branched structure. For example, in this invention, each of the C1-C6 alkyl groups is independently methyl, ethyl, propyl, butyl, pentyl, or hexyl; wherein, propyl is a C3 alkyl group (including isomers, such as n-propyl or isopropyl); butyl is a C4 alkyl group (including isomers, such as n-butyl, sec-butyl, isobutyl, or tert-butyl); pentyl is a C5 alkyl group (including isomers, such as n-pentyl, 1-methyl-butyl, 1-ethyl-propyl, 2-methyl-1-butyl, 3-methyl-1-butyl, isopentyl, tert-pentyl, or neopentyl); and hexyl is a C6 alkyl group (including isomers, such as n-hexyl or isohexyl).

[0142] As used herein, the term "alkoxy" refers to an alkyl group as defined above, which is connected via an oxygen bond (-O-).

[0143] In this invention, as a group or part of other groups, the term "Cn-m aryl" refers to a monocyclic or polycyclic aromatic group (with only carbon atoms as ring atoms) having n to m ring carbon atoms, possessing at least one carbon ring with a conjugated π-electron system. Examples of the aforementioned aryl unit include phenyl, naphthyl, indene, azulel, fluorenyl, phenanthryl, or anthraceneyl. In one embodiment, the aryl group is preferably a C6-14 aryl group, such as phenyl and naphthyl, more preferably phenyl.

[0144] In this invention, as a group or part of other groups, the term "nm-aryl" refers to an aromatic group whose ring atoms comprise one or more (e.g., 1, 2, 3, and 4) heteroatoms selected from nitrogen, oxygen, and sulfur, having n to m ring atoms. The heteroaryl group is a monocyclic, bicyclic, tricyclic, or tetracyclic system, wherein at least one ring is an aromatic ring. Heteroaryl groups within this definition include, but are not limited to: acridinel, carbazolyl, cyclophosphinyl, quinoxalinyl, pyrazolyl, indolyl, benzotriazolyl, furanyl, thiophene, benzothiophene, benzofuranyl, quinolinyl, isoquinolinyl, oxazolyl, isoxazolyl, pyrazinyl, pyridinyl, pyrimidinel, pyrroleyl, tetrahydroquinoline, imidazolyl, triazolyl, tetrazolyl, thiazolyl, isothiazolyl, furazolyl, thiadiazolyl, etc. Oxadiazole, pyridinyl, pyrazinyl, pyridazinyl, pyrimidinyl, triazinyl, purine, pteridinyl, naphridinyl, quinazolinyl, phthalazinyl, imidazopyridinyl, imidazothiazolyl, imidazooxazinyl, benzothiazolyl, benzooxazinyl, benzoimidazolyl, isoindolyl, indazole, pyrrolopyridinyl, thienopyridinyl, furanolopyridinyl, benzothiadiazole, benzooxadiazole, pyrrolopyrimidinyl, thienofuranyl. In one embodiment, as preferred examples of "5- to 18-membered heteroaryl groups", furanyl, thienoyl, pyrrololyl, imidazolyl, thiazolyl, pyrazolyl, oxazolyl, isoxazolyl, isothiazolyl, pyridinyl, pyrimidinyl, and carbazoleyl are listed, more preferably carbazoleyl.

[0145] As used herein, the term Cn-Cm cycloalkyl refers to a monocyclic or polycyclic alkyl group having n to m carbon atoms, such as 3-C10 cycloalkyl and C3-C6 cycloalkyl. Examples include adamantyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, and dicycloheptyl. In one embodiment, the C3-C10 cycloalkyl group is preferably adamantyl or cyclohexyl.

[0146] In this invention, the defined carbon number range of the group refers to any integer number of carbon atoms included within the defined range, such as C1 to C2. 20 This refers to the fact that the number of carbon atoms in the stated group can be 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19 or 20, C3-C. 10 This means that the number of carbon atoms in the group can be 3, 4, 5, 6, 7, 8, 9 or 10, and the range of carbon atoms for other groups can be deduced similarly.

[0147] Without violating common sense in the field, the above-mentioned preferred conditions can be combined arbitrarily to obtain various preferred embodiments of the present invention.

[0148] The reagents and raw materials used in this invention are all commercially available.

[0149] Compared with the prior art, the present invention has the following beneficial effects:

[0150] The boron-nitrogen compound of this invention, through extended conjugation and the introduction of nitrogen atoms, not only achieves fine-tuning of the spectrum but also further improves luminescence efficiency. The boron-nitrogen compound of this invention exhibits a narrow spectrum and can be used as a narrow-spectrum luminescent material to prepare the luminescent layer of organic electroluminescent devices. The organic electroluminescent devices prepared thereby achieve narrow-spectrum TADF emission with a full width at half maximum (FWHM) of less than 50 nm, and achieve an electroluminescent external quantum efficiency of over 34%. Attached Figure Description

[0151] Figure 1 This is a schematic diagram of the structure of the vacuum evaporation type organic electroluminescent device provided by the present invention, wherein 1 is the ITO anode, 2 is the hole transport layer 1, 3 is the hole transport layer 2, 4 is the light-emitting layer, 5 is the electron transport layer, 6 is the electron injection layer, and 7 is the metal cathode.

[0152] Figure 2 This is a schematic diagram of the solution-processed organic electroluminescent device provided by the present invention, wherein 1 is an ITO anode, 2 is a hole injection layer, 3 is a hole transport layer, 4 is a light-emitting layer, 5 is an electron transport layer, 6 is an electron injection layer, and 7 is a metal cathode.

[0153] Figure 3 The electroluminescence spectrum of the device using compound BN11 shows an emission peak at 532 nm and a full width at half maximum (FWHM) of 36 nm.

[0154] Figure 4 The electroluminescence spectrum of the device using compound BN12 is shown, with an emission peak at 528 nm and a full width at half maximum (FWHM) of 36 nm. Detailed Implementation

[0155] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0156] In embodiments of the present invention, the raw materials used to synthesize the shown compounds are as follows:

[0157] The raw material 1 specifically used includes the following molecules:

[0158]

[0159]

[0160] The specific raw material 2 used includes the following molecules:

[0161]

[0162] Synthesis Examples

[0163] The specific synthetic route involved in this invention is as follows:

[0164]

[0165]

[0166] R is * Represents the linking site of a functional group.

[0167] In the first step, BN-Mn (n = 1-12) (5 mmol) was dissolved in 60 mL of tetrahydrofuran, followed by the addition of pinacol diboron ester (5 mmol). The mixture was bubbled under nitrogen for 10 minutes, and then the catalysts methoxy(cyclooctadiene)iridium dimer (0.05 mmol) and 4,4'-di-tert-butyl-2,2'-bipyridine (0.1 mmol) were added. After stirring for 10 minutes, the mixture was heated to 66 °C and maintained with stirring for 12 hours. After the reaction was complete, the mixture was directly concentrated under reduced pressure and purified by column chromatography to obtain the intermediate BN-Mn-Bpin.

[0168] In the second step, 0.6 mmol of monobromopyridine biphenyl compound R-Br(B1-B4), 0.5 mmol of BN-Mn-Bpin (383 mg), 1 mmol of potassium carbonate (0.14 g), and 2 mL of water were added to 16 mL of tetrahydrofuran. The mixture was bubbled under nitrogen for 10 minutes, and 0.025 mmol of tetra(triphenylphosphine)palladium (28.9 mg) was added under high flow rate nitrogen. The mixture was heated to reflux and stirred for 12 hours. After the reaction system cooled to room temperature, the reaction mixture was extracted with dichloromethane and water, the organic phase was dried under vacuum, and then purified by column chromatography to obtain the precursor BN-M-Ni (i = 1-48).

[0169] In the third step, 0.3 mmol of BN-M-Ni (i = 1-48) was dissolved in 50 mL of ultra-dry dichloromethane, and 1.12 g of ferric chloride was dissolved in 10 mL of nitromethane. The mixture was degassed with liquid nitrogen for 30 min. The nitromethane mixture was slowly added dropwise under an ice-water bath, then slowly raised to room temperature, and the reaction was continued for 2 h. The reaction was quenched with 5 mL of methanol and 5 mL of water. The reaction mixture was extracted with dichloromethane and water, and the organic phase was dried under vacuum by heating. The product was then purified by column chromatography to obtain the target product BN-i (i = 1-48). Data on the obtained target compound are shown in Table 1.

[0170] Taking compound BN-9 as an example, the specific experimental details of the synthesis examples are explained below:

[0171] In the first step, 4.2 g of BN-M-3 (6.5 mmol) and 1.68 g of pinacol diborate (6.5 mmol) were dissolved in 60 mL of tetrahydrofuran. After bubbling under nitrogen for 10 minutes, 43.1 mg of methoxy(cyclooctadiene)iridium dimer (0.065 mmol) and 34.9 mg of 4,4'-di-tert-butyl-2,2'-bipyridine (0.13 mmol) were added. The mixture was stirred for 10 minutes, then heated to 66 °C and stirred for 12 hours. After the reaction was completed, the tetrahydrofuran was removed by concentration under reduced pressure. The residue was purified by column chromatography to obtain 4.5 g of BN-M-3-Bpin (yield 90%).

[0172] In the second step, 139 mg of monobromopyridine biphenyl B1 (0.6 mmol), 383 mg of BN-M-3-Bpin (0.5 mmol), 0.14 g of potassium carbonate (1 mmol), and 2 mL of water were added to tetrahydrofuran (16 mL). The mixture was bubbled under nitrogen for 10 minutes, and 28.9 mg of tetra(triphenylphosphine)palladium (0.025 mmol) was added under high flow nitrogen. The mixture was heated to reflux and stirred for 12 hours. After the reaction system cooled to room temperature, the reaction mixture was extracted with dichloromethane and water, the organic phase was dried under vacuum, and then purified by column chromatography to obtain 273.7 mg of the precursor BN-M-N9 (yield 69%).

[0173] In the third step, 396 mg of BN-M-N9 (0.5 mmol) was dissolved in 50 mL of ultra-dry dichloromethane, and 1.12 g of ferric chloride was dissolved in 10 mL of nitromethane. The mixture was degassed with liquid nitrogen for 30 min. The nitromethane mixture was slowly added dropwise under an ice-water bath, then slowly raised to room temperature, and the reaction was continued for 2 h. The reaction was quenched with 5 mL of methanol and 5 mL of water. The reaction mixture was extracted with dichloromethane and water, and the organic phase was dried under vacuum by heating. The product was then purified by column chromatography to obtain 316.6 mg of the target product, BN-9 (80% yield).

[0174] The products were characterized using an Agilent Technologies VarioMicro Cube instrument for elemental analysis, testing for C, H, and N. Mass spectrometry was performed using a Thermo Fisher TSQEndura ultra-high performance liquid chromatography-tandem triple quadrupole mass spectrometer.

[0175] Table 1. Summary of product data from the synthesis examples

[0176]

[0177]

[0178] Examples of electroluminescent devices

[0179] The following are some representative examples of electroluminescent devices. The molecular structures of some materials involved in these device examples are as follows:

[0180]

[0181] The following are examples of electroluminescent devices fabricated using the materials of the present invention, and the specific device fabrication process is as follows:

[0182] Vacuum evaporation device process:

[0183] The results of the device are as follows Figure 1 As shown, 1 is the ITO anode, 2 is hole transport layer 1, 3 is hole transport layer 2, 4 is the light-emitting layer, 5 is the electron transport layer, 6 is the electron injection layer, and 7 is the metal cathode.

[0184] The preparation process is as follows:

[0185] (1) Substrate treatment: Transparent ITO glass was used as the substrate material for device fabrication. It was first ultrasonically treated with 5% ITO cleaning solution for 30 minutes, then sequentially ultrasonically washed with distilled water (twice), acetone (twice), and isopropanol (twice). Finally, the ITO glass was stored in isopropanol. Before each use, the surface of the ITO glass was carefully wiped with acetone and isopropanol cotton balls, rinsed with isopropanol, dried, and then plasma-treated for 5 minutes before use. Device fabrication was completed using a combination of spin coating and vacuum evaporation processes.

[0186] (2) Preparation of hole injection layer and hole transport layer: The hole transport layer is prepared by evaporation process. When the vacuum degree of the vacuum evaporation system reaches 5×10 -4 Vacuum deposition begins when the pressure is below a certain level. The deposition rate is determined using a SAINS film thickness gauge. Organic hole transport layers are sequentially deposited on the ITO electrode surface using a vacuum evaporation process. The deposition rate of the hole transport material is [missing information].

[0187] (3) Preparation of the light-emitting layer: The light-emitting layer is prepared by evaporation deposition process. When the vacuum degree of the vacuum evaporation deposition system reaches 5×10 - 4 Vacuum deposition begins when the pressure is below a certain level (Pa). The deposition rate is determined using a SAINS film thickness gauge. The luminescent layer is sequentially deposited on the hole transport layer using a vacuum evaporation process. The deposition rate of the luminescent layer material is [missing information].

[0188] (4) Fabrication of electron transport layer, electron injection layer and metal electrode: The electron transport layer, electron injection layer and metal electrode are fabricated using a vapor deposition process. When the vacuum degree of the vacuum deposition system reaches 5×10 -4Vapor deposition begins when the pressure is below a certain level (Pa). The deposition rate is measured using a SAINS film thickness gauge. An organic electron transport layer, a LiF electron injection layer, and a metal Al electrode are sequentially deposited on the light-emitting layer using a vacuum evaporation process (see the following effect example for specific device structure). The deposition rate of the organic material is [missing information - likely a specific value]. The deposition rate of LiF is The deposition rate of Al is

[0189] Solution-processed device fabrication process:

[0190] The results of the device are as follows Figure 2 As shown, 1 is the ITO anode, 2 is the hole injection layer, 3 is the hole transport layer, 4 is the light-emitting layer, 5 is the electron transport layer, 6 is the electron injection layer, and 7 is the metal cathode.

[0191] The preparation process is as follows:

[0192] (1) Substrate treatment: Transparent ITO glass was used as the substrate material for device fabrication. It was first ultrasonically treated with 5% ITO cleaning solution for 30 minutes, then sequentially ultrasonically washed with distilled water (twice), acetone (twice), and isopropanol (twice). Finally, the ITO glass was stored in isopropanol. Before each use, the surface of the ITO glass was carefully wiped with acetone and isopropanol cotton balls, rinsed with isopropanol, dried, and then plasma-treated for 5 minutes before use. Device fabrication was completed using a combination of spin coating and vacuum evaporation processes.

[0193] (2) Preparation of hole injection layer and hole transport layer: First, a 20 nm thick layer of PEDOT:PSS (poly(3,4-ethylenedioxythiophene):polystyrene sulfonate) was spin-coated on the ITO surface as a hole injection layer. Then, a 50 nm thick layer of Poly-HTL was spin-coated on the hole injection layer as a hole transport layer. Then, the ITO glass with the hole injection layer and the hole transport layer was placed in a glove box under nitrogen protection and annealed at 200 °C for 30 minutes (to allow Poly-HTL to crosslink).

[0194] (3) Preparation of luminescent layer: The main material and the luminescent material are dissolved in xylene at a ratio of 97wt%:3wt% (wt% is the weight percentage concentration) to prepare a solution with a concentration of 2wt%. The luminescent layer is prepared by spin coating using the prepared solution. The thickness of the luminescent layer is 50nm.

[0195] (4) Fabrication of electron transport layer, electron injection layer and metal electrode: The electron transport layer, electron injection layer and metal electrode are fabricated using a vapor deposition process. When the vacuum degree of the vacuum deposition system reaches 5×10 -4Vapor deposition begins when the pressure is below a certain level (Pa). The deposition rate is measured using a SAINS film thickness gauge. An organic electron transport layer, a LiF electron injection layer, and a metal Al electrode are sequentially deposited on the light-emitting layer using a vacuum evaporation process (see the following effect example for specific device structure). The deposition rate of the organic material is [missing information - likely a specific value]. The deposition rate of LiF is The deposition rate of Al is

[0196] Device Examples A1-A24 (fabricated using vacuum evaporation device technology)

[0197] Organic electroluminescent devices (structure as shown in device embodiments A1-A24) Figure 1 In the example shown, TAPC is used as hole transport layer 1, TCTA as hole transport layer 2, H1-48 is used as the host material in the light-emitting layer, BN-1 to BN-24 are used as doped light-emitting materials (doping concentration of 3wt%), TRZ-8 is used as the electron transport material, LiF is used as the electron injection layer, and Al is used as the metal cathode. The structure of the organic electroluminescent device in the example is [ITO / TAPC (50nm) / TCTA (5nm) / 97wt%H-48+3wt%BN-n (30nm) / TRZ-8 (30nm) / LiF (1nm) / Al (100nm)] (n=1-24).

[0198] The device's current, voltage, luminance, and emission spectrum characteristics were simultaneously tested using a Photo Research PR 655 spectrophotometer and a Keithley K 2400 digital source meter system. Performance testing was conducted at room temperature and under ambient conditions. The external quantum efficiency (EQE) of the device was calculated based on the Lambaugh distribution of emission, using current density, luminance, and electroluminescence spectrum combined with the apparent function.

[0199] Device Examples A25-A48 (fabricated using solution processing device technology)

[0200] Organic electroluminescent devices (structure as shown in device embodiments A25-A48) Figure 2In the example shown, PEDOT:PSS is used as the hole injection layer, Poly-HTL as the hole transport layer, H1-48 is used as the host material in the light-emitting layer, BN-25 to BN-48 are used as doped light-emitting materials (doping concentration of 3wt%), TRZ-8 is used as the electron transport material, LiF is used as the electron injection layer, and Al is used as the metal cathode. The structure of the organic electroluminescent device in the example is [ITO / PEDOT:PSS (20nm) / Poly-HTL (50nm) / 97wt%H1-48+3wt%BNn / TRZ-8 (50nm) / LiF (1nm) / Al (100nm)] (n=25-48).

[0201] The device's current, voltage, luminance, and emission spectrum characteristics were simultaneously tested using a Photo Research PR 655 spectrophotometer and a Keithley K 2400 digital source meter system. Performance testing was conducted at room temperature and under ambient conditions. The external quantum efficiency (EQE) of the device was calculated based on the Lambaugh distribution of emission, using current density, luminance, and electroluminescence spectrum combined with the apparent function.

[0202] The test results are shown in Table 2.

[0203] Table 2

[0204]

[0205]

[0206] The implementation data of the electroluminescent device listed in Table 2 prove that the luminescent material provided by the present invention can be used to prepare high-efficiency organic electroluminescent devices, and the electroluminescence spectrum has narrow band characteristics, with a full width at half maximum (FWHM) of less than 50 nm and an external quantum efficiency of more than 35%.

[0207] Device Examples B1-B24 (fabricated using vacuum evaporation device technology)

[0208] Organic electroluminescent devices (structure as shown in device embodiments B1-B24) Figure 1In the example shown, TAPC is used as hole transport layer 1, TCTA is used as hole transport layer 2, H1-48+TRZ-79 is used as the host material in the light-emitting layer, BN-1 to BN-24 are used as doped light-emitting materials (doping concentration is 3wt%), TRZ-8 is used as the electron transport material, LiF is used as the electron injection layer, and Al is used as the metal cathode. The structure of the organic electroluminescent device in the example is [ITO / TAPC (50nm) / TCTA (5nm) / 67wt%H-48+30wt%TRZ-79+3wt%BN-n (30nm) / TRZ-8 (30nm) / LiF (1nm) / Al (100nm)] (n=1-24).

[0209] The device's current, voltage, luminance, and emission spectrum characteristics were simultaneously tested using a Photo Research PR 655 spectrophotometer and a Keithley K 2400 digital source meter system. Performance testing was conducted at room temperature and under ambient conditions. The external quantum efficiency (EQE) of the device was calculated based on the Lambaugh distribution of emission, using current density, luminance, and electroluminescence spectrum combined with the apparent function.

[0210] Device Examples B25-B48 (fabricated using solution-processed device technology)

[0211] Organic electroluminescent devices (structure as shown in device embodiments B25-B48) Figure 2 In the example shown, PEDOT:PSS is used as the hole injection layer, Poly-HTL is used as the hole transport layer, H1-48+TRZ-79 is used as the host material in the light-emitting layer, BN-25 to BN-48 are used as doped light-emitting materials (doping concentration is 3wt%), TRZ-8 is used as the electron transport material, LiF is used as the electron injection layer, and Al is used as the metal cathode. The structure of the organic electroluminescent device in the example is [ITO / PEDOT:PSS (20nm) / Poly-HTL (50nm) / 67wt%H1-48+30wt%TRZ-79+3wt%BNn / TRZ-8 (50nm) / LiF (1nm) / Al (100nm)] (n=25-48).

[0212] The device's current, voltage, luminance, and emission spectrum characteristics were simultaneously tested using a Photo Research PR 655 spectrophotometer and a Keithley K 2400 digital source meter system. Performance testing was conducted at room temperature and under ambient conditions. The external quantum efficiency (EQE) of the device was calculated based on the Lambaugh distribution of emission, using current density, luminance, and electroluminescence spectrum combined with the apparent function.

[0213] Similarly, the device performance was tested by measuring the peak position and full width at half maximum (FWHM) of its electroluminescence spectrum, as well as its external quantum efficiency. The test results are shown in Table 3.

[0214] Table 3

[0215]

[0216]

[0217] The implementation data of the electroluminescent device listed in Table 3 prove that the luminescent material provided by the present invention can be used to prepare high-efficiency organic electroluminescent devices, and the electroluminescence spectrum has narrow band characteristics, with a half-width of less than 50 nm and an external quantum efficiency of more than 36%.

[0218] An example is provided showing the electroluminescence spectra (PhotoResearch PR 655 spectra) of devices using compounds BN11 and BN12. Figure 3 The image shows the electroluminescence spectrum of compound BN11, with an emission peak at 532 nm and a full width at half maximum (FWHM) of 36 nm. Figure 4 The image shows the electroluminescence spectrum of compound BN12, with an emission peak at 528 nm and a full width at half maximum (FWHM) of 35 nm.

[0219] The applicant declares that the boron nitrogen compound, its preparation method, and its application are illustrated by the above embodiments, but the present invention is not limited to the above embodiments, that is, it does not mean that the present invention must rely on the above embodiments to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions of the raw materials used in the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A boron-nitrogen compound, characterized in that, The boron-nitrogen compound has the structure shown in Formula I: ； W, X, Y, and Z represent CH or N, and one of W, X, Y, and Z is N, while the rest are CH; The R 1 and R 2 Independently H, methyl, , phenyl, , , , , , , , , , or The wavy line represents the connection site of the functional group.

2. The boron-nitrogen compound according to claim 1, characterized in that, The boron-nitrogen compound is a compound represented by formula I-1, I-2, I-3 or I-4 as follows: ； Where R 1 and R 2 The limitations are the same as in Equation I.

3. The boron-nitrogen compound according to claim 1 or 2, characterized in that, The R 1 and R 2 same.

4. A boron-nitrogen compound, characterized in that, The boron-nitrogen compound is any one of the following compounds: 。 5. The method for preparing the boron-nitrogen compound according to any one of claims 1-4, characterized in that, The preparation method includes the following steps: (1) Compound BN-Mn reacts with pinacol diboronic acid ester to give compound BN-Mn-Bpin, and the reaction formula is as follows: ； (2) Compound BN-Mn-Bpin undergoes a coupling reaction with R-Br to give compound BN-M-Ni, as shown in the following reaction formula: ； Where R is , where the wavy line represents the connection site of the group; (3) Compound BN-M-Ni undergoes a cyclization reaction in the presence of ferric chloride to give the boron-nitrogen compound shown in Formula I, as follows: 。 6. The preparation method according to claim 5, characterized in that, The molar ratio of compound BN-Mn to pinacol diboronic acid ester in step (1) is 1:1~10.

7. The preparation method according to claim 5, characterized in that, The reaction in step (1) is carried out in the presence of a catalyst, which is a methoxy(cyclooctadiene)iridium(I) dimer and 4,4'-di-tert-butyl-2,2'-bipyridine.

8. The preparation method according to claim 7, characterized in that, The molar ratio of the catalyst methoxy(cyclooctadiene)iridium(I) dimer, 4,4'-di-tert-butyl-2,2'-bipyridine to BN-Mn in step (1) is 0.1%~10%:0.2%~20%:

1.

9. The preparation method according to claim 5, characterized in that, The solvent for the reaction in step (1) is tetrahydrofuran.

10. The preparation method according to claim 5, characterized in that, The reaction in step (1) is carried out at a temperature of 60~100℃ for 6~24 hours.

11. The preparation method according to claim 5, characterized in that, In step (2), the molar ratio of compound BN-Mn-Bpin to compound R-Br is 1:0.8~2.

12. The preparation method according to claim 5, characterized in that, The reaction described in step (2) is carried out in the presence of a weakly basic substance.

13. The preparation method according to claim 12, characterized in that, The weakly alkaline substance is potassium carbonate.

14. The preparation method according to claim 5, characterized in that, The reaction in step (2) is carried out in the presence of a catalyst, which is tetra(triphenylphosphine)palladium.

15. The preparation method according to claim 14, characterized in that, The amount of catalyst used in step (2) is 0.1%-15% of the mass of compound BN-Mn-Bpin.

16. The preparation method according to claim 5, characterized in that, The solvent for the reaction in step (2) is tetrahydrofuran.

17. The preparation method according to claim 5, characterized in that, The reaction described in step (2) is carried out under reflux.

18. The preparation method according to claim 5, characterized in that, The reaction time in step (2) is 5-24 hours.

19. The preparation method according to claim 5, characterized in that, The amount of ferric chloride used in step (3) is 10 to 50 times the amount of compound BN-M-Ni.

20. The preparation method according to claim 5, characterized in that, The solvent for the cyclization reaction in step (3) is dichloromethane.

21. The preparation method according to claim 5, characterized in that, The cyclization reaction described in step (3) is carried out at room temperature.

22. The preparation method according to claim 5, characterized in that, The time for the cyclization reaction in step (3) is 1-8 hours.

23. The preparation method according to claim 5, characterized in that, The reactions described in steps (2) and (3) are carried out under nitrogen protection.

24. An organic electroluminescent composition, characterized in that, It includes the boron nitride compound as a dopant material as described in any one of claims 1-4 and the host material.

25. The organic electroluminescent composition according to claim 24, characterized in that, The host material is a material with electron transport capability and / or hole transport capability, and its triplet excited state energy is higher than or equal to the triplet excited state energy of the doped material.

26. The organic electroluminescent composition according to claim 24, characterized in that, The host material is a carbazole derivative and / or a carbline derivative having a structure as shown in any one of formulas (H-1) to (H-6): ； Where X1, Y1, and Z1 are CH or N, and at most one of X1, Y1, and Z1 is N; Where R 1H and R 2H Independently, it can be any of the following groups: ； Where X2, Y2, and Z2 are CH or N, and at most one of X2, Y2, and Z2 is N; Where R aH and R bH Independent of H, C1-C 20 Alkyl, C1-C 20 Alkoxy, C6-C 20 Aryl, C1-C 20 Alkyl-substituted C6-C 20 Aryl or C1-C 20 Alkoxy-substituted C6-C 20 Aryl group, * indicates the linking site of the group.

27. The organic electroluminescent composition according to claim 26, characterized in that, The organic electroluminescent composition contains 0.3-30.0 wt% of the boron nitrogen compound as described in any one of claims 1-4 as a dopant material, and the remaining 99.7-70.0 wt% is a host material composed of 1-2 compounds having the structure of formula (H-1) to formula (H-6).

28. The organic electroluminescent composition according to claim 27, characterized in that, The main material contains two compounds having structures of formula (H-1) to (H-6), with a weight ratio of 1:5 to 5:1 between the two compounds.

29. The organic electroluminescent composition according to claim 24, characterized in that, The host material in the organic electroluminescent composition is one or two of compounds H1-1 to H1-427; 。 30. The organic electroluminescent composition according to claim 29, characterized in that, The organic electroluminescent composition contains 0.3-30.0 wt% of a boron nitrogen compound with the structure of Formula I as described in any one of claims 1-4, and the remaining 99.7-70.0 wt% is one or two compounds selected from H1-1 to H1-427.

31. The organic electroluminescent composition according to claim 30, characterized in that, The organic electroluminescent composition contains two compounds from H1-1 to H1-427 as the main material, with a weight ratio of 1:5 to 5:1 between the two compounds.

32. The organic electroluminescent composition according to claim 26, characterized in that, The doping material in the organic electroluminescent composition is any one of the boron nitrogen compounds of any one of claims 1-4; the main material is composed of any one of the compounds shown in formula Trz1-A, Trz2-A, Trz3-A, Trz4-A, Trz5-A or Trz6-A and any one of the compounds having the structure shown in formulas H-1 to H-6. ； Where R 1a R 1b R 2a R 2b R 3a and R 3b One or two of them are independent as R Tz The remaining elements are, independently and identically, hydrogen, deuterium, C1-C8 alkyl, C1-C8 alkoxy, or C6-C4. 18 Aryl, C1-C8 alkyl substituted C6-C 18 Aryl or C1-C8 alkoxy-substituted C6-C 18 aryl; R Tz Any of the substituents shown in the following formula: ； The asterisk represents the linking site of the functional group.

33. The organic electroluminescent composition according to claim 32, characterized in that, The weight ratio between the compounds shown in Trz1-A, Trz2-A, Trz3-A, Trz4-A, Trz5-A or Trz6-A and the compounds shown in H-1, H-2, H-3, H-4, H-5 or H-6 in the main material is 1:20 to 20:

1.

34. The organic electroluminescent composition according to claim 29, characterized in that, The doping material in the organic electroluminescent composition is any one of the boron nitrogen compounds according to any one of claims 1-4; the main material is composed of any one of the compounds shown in formula TRZ-1 to TRZ-80 and any one of the carbazole or carboline derivatives shown in formula H1-1 to H1-427. 。 35. The organic electroluminescent composition according to claim 34, characterized in that, The weight ratio of the compound represented by formula TRZ-1 to TRZ-80 in the main material to the carbazole or carbline derivative is 1:20 to 20:

1.

36. An organic electroluminescent material, characterized in that, The organic electroluminescent material includes a boron nitrogen compound as described in any one of claims 1-4 or an organic electroluminescent composition as described in any one of claims 24-35.

37. An organic electroluminescent device, characterized in that, The organic electroluminescent device comprises an anode and a cathode, and an organic thin film layer disposed between the anode and the cathode. The organic thin film layer includes a light-emitting layer, an optional hole injection layer, an optional hole transport layer, an optional electron transport layer, and an optional electron injection layer, wherein at least one of the light-emitting layer, electron injection layer, electron transport layer, hole transport layer, and hole injection layer comprises a boron nitrogen compound as described in any one of claims 1-4 or an organic electroluminescent composition as described in any one of claims 24-35.

38. The organic electroluminescent device according to claim 37, characterized in that, The light-emitting layer comprises a boron nitrogen compound as described in any one of claims 1-4 or an organic electroluminescent composition as described in any one of claims 24-35.

39. The organic electroluminescent device according to claim 37, characterized in that, The organic electroluminescent device further includes an optional hole blocking layer, an optional electron blocking layer, and an optional capping layer.

40. The use of the organic electroluminescent device according to any one of claims 37-39 in an organic electroluminescent display or an organic electroluminescent lighting source.

Images