Organic light-emitting device

Abstract

The invention relates to an organic light-emitting device and a display device, in particular to an organic light-emitting device adopting a sensitizer and a boron-nitrogen heterocyclic ring narrow-band fluorescent material as a luminescent dye, and belongs to the technical field of organic electroluminescence. The boron-nitrogen heterocyclic ring narrow-band fluorescent material disclosed by the invention is selected from a structure as shown in the following formula. The main body material of the light-emitting layer in the device can be selected from a wide-band gap material, a thermal activation delayed fluorescence (TADF) material and an exciplex main body material, and the sensitizer is selected from a phosphorescent sensitizer or a thermal activation delayed fluorescence sensitizer. The organic electroluminescent device provided by the invention is relatively high in electroluminescent external quantum efficiency and small in efficiency roll-off under high brightness, and meanwhile, the device shows excellent color purity.

Description

Technical Field

[0001] This invention relates to an organic electroluminescent device and a display device, specifically an organic electroluminescent device employing a sensitizer and a boron-nitrogen heterocyclic narrow-band fluorescent material as a luminescent dye, belonging to the field of organic electroluminescence technology. Background Technology

[0002] Organic light-emitting diodes (OLEDs) are devices that emit light through electrical current. Their key characteristic comes from their organic light-emitting layer. When an appropriate voltage is applied, electrons and holes combine in the organic light-emitting layer to generate excitons, which emit light of different wavelengths depending on the properties of the layer. Currently, the light-emitting layer consists of a host material and doped dyes, with the dyes often selected from traditional fluorescent materials, phosphorescent materials, or thermally activated delayed fluorescence (TADF) materials.

[0003] Specifically, traditional fluorescent materials have the drawback of not being able to utilize triplet excitons. While phosphorescent materials can achieve 100% energy utilization efficiency by introducing heavy metal atoms, such as iridium or platinum, to enable singlet exciton transitions to the triplet state, these heavy metals are extremely scarce, expensive, and cause significant environmental pollution. Therefore, phosphorescent materials are not the preferred choice for dyes. Thermally Activated Delayed Fluorescence (TADF) materials, compared to phosphorescent and traditional fluorescent materials, can absorb ambient heat to achieve reverse intersystem crossings from the triplet exciton to the singlet state, emitting fluorescence from the singlet state. This achieves 100% exciton utilization without the need for any heavy metals. Therefore, currently, 100% energy utilization efficiency is mainly achieved by doping the host material with TADF. The singlet exciton can then return to the ground state and emit fluorescence, achieving 100% exciton utilization without the need for any heavy metals. Currently, high luminescence efficiency is mainly achieved by doping the host material with TADF. However, most TADF materials also have certain defects, such as excessively broad emission spectra, large device roll-off, and short lifetime. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides an organic electroluminescent device employing a sensitization scheme. This organic electroluminescent device utilizes a material selected from phosphorus photosensitizers or thermally activated delayed fluorescence sensitizers, co-doped with a boron-nitrogen narrow-band fluorescent dye in the host material of the emitting layer. The host material can be selected from wide-bandgap materials or materials with TADF properties. The device of this invention achieves 100% exciton utilization, and the resulting OLEDs exhibit high efficiency and low roll-off.

[0005] Specifically, the present invention proposes an organic electroluminescent device, comprising a substrate, a first electrode, a second electrode, and an organic functional layer, wherein the organic functional layer includes an organic light-emitting layer, and the organic light-emitting layer includes a host material and a light-emitting dye, characterized in that the light-emitting layer includes a light-emitting host material, a sensitizer, and a boron-nitrogen heterocyclic narrow-band fluorescent material used as a light-emitting dye;

[0006] The triplet energy level of the host material in the luminescent layer is higher than that of the sensitizer, and the triplet energy level of the host material is also higher than that of the boron-nitrogen heterocyclic narrow-band fluorescent material.

[0007] The triplet energy level of the sensitizer is higher than the singlet and triplet energy levels of the boron-nitrogen heterocyclic narrowband fluorescent material, and the HOMO energy level of the sensitizer is deeper than the HOMO energy level of the boron-nitrogen heterocyclic narrowband fluorescent material.

[0008] The sensitizer is selected from phosphorescent sensitizers or thermally activated delayed fluorescence sensitizers.

[0009] The boron-nitrogen heterocyclic narrow-band fluorescent material of the present invention is selected from the structure shown in formula (1):

[0010]

[0011] Among them, R 1 ~R 10 Each group is independently selected from hydrogen, deuterium, halogen, hydroxyl, carboxyl, nitro, cyano, sulfone, sulfoxide, alkynyl, or unsubstituted or R'-substituted groups of the following: C1-C30 chain alkyl, C3-C30 cycloalkyl, C1-C10 alkoxy, C1-C10 thioalkyl, C6-C30 acyl, C6-C30 amino, C6-C30 arylamino, C3-C30 heteroarylamino, C6-C60 monocyclic aryl, C6-C60 fused-ring aryl, C6-C60 aryloxy, C6-C60 arylphosphinyl, C5-C60 monocyclic heteroaryl, C5-C60 fused-ring heteroaryl, C6-C30 alkylsilyl, C6-C30 arylsilyl, or C6-C30 heteroarylsilyl.

[0012] The R' is independently selected from one of deuterium, halogen, cyano, C1-C30 chain alkyl, C3-C30 cycloalkyl, C1-C10 alkoxy, C6-C60 arylamino, C3-C60 heteroarylamino, C6-C60 aryl, and C3-C60 heteroaryl.

[0013] More preferably, in formula (1), R 1 ~R 10Each group is independently selected from hydrogen, deuterium, or one or more combinations of the following groups: methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, 2-methylbutyl, n-pentyl, sec-pentyl, cyclopentyl, neopentyl, n-hexyl, cyclohexyl, neohexyl, n-heptyl, cycloheptyl, n-octyl, cyclooctyl, 2-ethylhexyl, trifluoromethyl, pentafluoroethyl, 2,2,2-trifluoroethyl, ethynyl, trimethylsilylethynyl, tert-butylethynyl, triisopropylsilylethynyl, phenyl, tert-butylphenyl, naphthyl, anthracene, benzo[a]anthrayl, phenanthryl, benzo[a]phenanthryl, pyrene, peryl, uryl, fluoranyl, azulene, tetraphenyl, pentaphenyl, benzo[a]pyrene, biphenyl, azabiphenyl, azobiphenyl, terphenyl, Phenylacetyl, naphthylphenyl, phenyl terphenyl, tetraphenyl, fluorenyl, spirodifluorenyl, benzo[a]fluorenyl, dibenzo[a]fluorenyl, dihydrophenanthrene, dihydropyrene, tetrahydropyrene, cis or trans indo[a]fluorenyl, indene, trimerinyl, isotrimerininyl, spirotrimerininyl, spiroisotrimerininyl, triphenylene, furanyl, benzo[a]furanyl, isobenzo[a]furanyl, dibenzo[a]furanyl, thiazolyl Fenyl, benzothiophene, isobenzothiophene, dibenzothiophene, pyrrole, indole, isoindole, benzoindole, carbazole, benzocarbazole, indocarbazole, dibenzocarbazole, pyridyl, bipyridyl, quinolinyl, isoquinolinyl, cenolinyl, quinazolinyl, benzoquinazolinyl, benzodioxanepentenyl, acridine, dihydroacridyl, phenanthridine, benzene benzo-5,6-quinolinyl, benzo-6,7-quinolinyl, benzo-7,8-quinolinyl, pyrazolyl, indazoleyl, imidazoleyl, benzimidazoleyl, naphthomidazoleyl, phenanthrenemidazoleyl, pyridiniumimazoleyl, pyraziniumimazoleyl, quinoxaloylimazoleyl, oxazolyl, isoxazolyl, benzoxazolyl, benzoisoxazolyl, naphthomidazoleyl, anthraquinoxazolyl, phenanthrenemidazoleyl 1,2-Thiazolyl, 1,3-Thiazolyl, benzothiazolyl, benzoisothiazolyl, pyridinyl, benzopyridinyl, pyrimidinyl, benzopyrimidinyl, quinoxalinyl, benzoquinoxalinyl, 5,10-diazathanel, 2,7-diazapyrene, 2,3-diazapyrene, 1,6-diazapyrene, 1,8-diazapyrene, 4,5-diazapyrene, 4 5,9,10-Tetraazaperyl, Pyrazinyl, Phenazinyl, Phenoxazinyl, Phenthiazinyl, Naphridinyl, Azacarbazolyl, Benzocarbazolyl, Phenanthrolinel, 1,2,3-Triazolyl, 1,2,4-Triazolyl, Benzotriazolyl, 1,2,3-Oxadiazolyl, 1,2,4-Oxadiazolyl, 1,2,5-Oxadiazolyl, 1,2,3-Thiadiazolyl 1,2,4-Thiadiazolyl, 1,2,5-Thiadiazolyl, 1,3,4-Thiadiazolyl, 1,3,5-Triazinyl, 1,2,4-Triazinyl, 1,2,3-Triazinyl, Tetrazolyl, 1,2,4,5-Tetrazinyl, 1,2,3,4-Tetrazinyl, 1,2,3,5-Tetrazinyl, Purinyl, Pteridyl, Indazinyl, Benzothiadiazolyl, 9,9-Dimethylacridyl, triarylamine, adamantyl, fluorophenyl, methylphenyl, trimethylphenyl, cyanophenyl, tetrahydropyrrolyl, piperidinyl, methoxy, trisenel, cyclosenel, tetrastyrene, naphthimide, triphenylboryl, cycloheptanetrienyl, trimethylsilyl, triethylsilyl, triisopropylsilyl, triphenylsilyl, dimethylphenylsilyl, diphenylmethylsilyl, or tert-butyldiphenylsilyl.

[0014] More preferably, the boron-nitrogen heterocyclic narrow-band fluorescent material of the present invention has the structure shown in formula (2):

[0015]

[0016] Wherein group R 9 R 10 The limitation is the same as the definition in equation (1) above;

[0017] Preferably, the R 9 R 10 Selected independently

[0018]

[0019]

[0020]

[0021]

[0022] in Indicates the linking site of a functional group.

[0023] More preferably, the boron-nitrogen heterocyclic narrow-band fluorescent material of the present invention is selected from compounds with the following specific structures:

[0024]

[0025]

[0026]

[0027]

[0028]

[0029]

[0030]

[0031]

[0032]

[0033]

[0034]

[0035]

[0036]

[0037]

[0038]

[0039]

[0040]

[0041]

[0042]

[0043]

[0044]

[0045]

[0046]

[0047]

[0048]

[0049]

[0050] In the organic electroluminescent device of the present invention, the host material of the light-emitting layer may be selected from wide-bandgap materials, thermally activated delayed fluorescence (TADF) materials, and exciton complex-type host materials. The wide-bandgap material is selected from at least one compound chosen from carbazole derivatives, carboline derivatives, spirofluorene derivatives, fluorene derivatives, silicon-based derivatives, phosphoxy-based derivatives, and sulfone-based derivatives; the thermally activated delayed fluorescence material is selected from at least one compound chosen from benzonitrile derivatives, carbazole derivatives, spirofluorene derivatives, thiazole derivatives, and triazine derivatives.

[0051] Preferably, the main material of the present invention is selected from, but not limited to, any of the compounds shown in the following structures:

[0052]

[0053]

[0054]

[0055]

[0056]

[0057] The host material of the excitocomplex includes a donor material and an acceptor material. The donor material of the excitocomplex is selected from at least one compound selected from indolecarbazole derivatives, carbazole derivatives, furan derivatives, thiophene derivatives, spirofluorene derivatives, fluorene derivatives, silicon-containing derivatives, and diphenylamine derivatives.

[0058] Preferably, the donor material of the excitocomplex is selected from, but not limited to, compounds shown in any of the following structures:

[0059]

[0060]

[0061] The acceptor material of the excitokinin complex is selected from at least one compound selected from triazine derivatives, pyridone derivatives, imidazole derivatives, o-phenanthroline derivatives, thiophene derivatives, fentanyl derivatives, spirofluorene derivatives, fluorene derivatives, silicon-containing derivatives, cyano-containing derivatives, phosphooxy-containing derivatives, and sulfone-containing derivatives.

[0062] Preferably, the receptor material of the excitokinesin complex is selected from, but not limited to, compounds shown in any of the following structures:

[0063]

[0064]

[0065]

[0066] In the organic electroluminescent device of the present invention, when the sensitizer is selected from phosphorescent photosensitizers, it is specifically selected from, but not limited to, one of the following compounds:

[0067]

[0068]

[0069]

[0070]

[0071] In the organic electroluminescent device of the present invention, when the sensitizer is selected from thermally activated delayed fluorescence sensitizers, it is selected from benzonitrile derivatives or carbazole derivatives, and is selected from, but not limited to, one of the compounds shown in the following structural formulas:

[0072]

[0073]

[0074]

[0075] In this specification, the expression of Ca to Cb means that the number of carbon atoms in the group is a to b. Unless otherwise specified, the number of carbon atoms in the group generally does not include the number of carbon atoms in the substituent.

[0076] In this specification, the way a ring structure is represented by "—" indicates that the connection point is located at any position on the ring structure where bonding can occur.

[0077] In this specification, "each independently" means that when there are multiple subjects, they may be the same or different from each other.

[0078] In this invention, the description of chemical elements, unless otherwise specified, usually includes the concept of their isotopes. For example, the description of "hydrogen (H)" includes the concept of its isotopes 1H (protium or H) and 2H (deuterium or D); carbon (C) includes 12C, 13C, etc., which will not be elaborated further.

[0079] The heteroatom in the present invention generally refers to an atom or an atomic group selected from N, O, S, P, Si and Se, preferably selected from N, O and S.

[0080] In the present specification, examples of halogen include fluorine, chlorine, bromine, and iodine.

[0081] In the present invention, unless otherwise specified, aryl and heteroaryl include both monocyclic and condensed ring forms.

[0082] In this invention, C6-C60 can be C6, C9, C10, C12, C14, C16, C18, C20, C22, C24, C26, C28, C30, C32, C34, C36, C38, C40, C42, C44, C46, ​​C48, C50, C52, C54, C56, or C58, etc.

[0083] C3-C60 can all be C3, C4, C5, C6, C9, C10, C12, C14, C16, C18, C20, C22, C24, C26, C28, C30, C32, C34, C36, C38, C40, C42, C44, C46, ​​C48, C50, C52, C54, C56, or C58, etc.

[0084] C1-C20 can all be C2, C3, C4, C5, C6, C7, C8, C9, C10, C11, C12, C13, C14, C15, C16, C17, C18 or C19, etc.

[0085] C3-C20 can all be C3, C4, C5, C6, C7, C8, C9, C10, C11, C12, C13, C14, C15, C16, C17, C18 or C19, etc.

[0086] C6-C30 can all be C6, C9, C10, C12, C14, C16, C18, C20, C22, C24, C26 or C28, etc.

[0087] C3-C30 can all be C3, C4, C5, C6, C9, C10, C12, C14, C16, C18, C20, C22, C24, C26 or C28, etc.

[0088] C2-C10 can all be C2, C3, C4, C5, C6, C7, C8, C9 or C10.

[0089] In this invention, the substituted or unsubstituted C6-C60 aryl (or C6-C50 aryl) includes monocyclic aryl and fused-ring aryl, preferably C6-C30 aryl, and more preferably C6-C20 aryl. A monocyclic aryl refers to a molecule containing at least one phenyl group. When a molecule contains at least two phenyl groups, the phenyl groups are independent of each other and connected by a single bond, exemplarily such as phenyl, biphenyl, and terphenyl. Specifically, the biphenyl includes 2-biphenyl, 3-biphenyl, and 4-biphenyl; the terphenyl includes p-terphenyl-4-yl, p-terphenyl-3-yl, p-terphenyl-2-yl, meta-terphenyl-4-yl, meta-terphenyl-3-yl, and meta-terphenyl-2-yl. A fused-ring aryl refers to a molecule containing at least two aromatic rings, where the aromatic rings are not independent of each other but share two adjacent carbon atoms fused together. For example, naphthyl, anthracenyl, phenanthrenyl, indenyl, fluorenyl, fluoranthenyl, triphenylene, pyrenyl, perylene, Naphthyl, 2-naphthyl, and their derivative groups, etc. The naphthyl includes 1-naphthyl or 2-naphthyl; the anthraceneyl is selected from 1-anthrayl, 2-anthrayl, and 9-anthrayl; the fluorenyl is selected from 1-fluorenyl, 2-fluorenyl, 3-fluorenyl, 4-fluorenyl, and 9-fluorenyl; the pyrene is selected from 1-pyrene, 2-pyrene, and 4-pyrene; the 2-tetraphenyl is selected from 1-2 ... The fluorene derivative group is selected from 9,9-dimethylfluorenyl, 9,9-diethylfluorenyl, 9,9-dipropylfluorenyl, 9,9-dibutylfluorenyl, 9,9-dipentylfluorenyl, 9,9-dihexylfluorenyl, 9,9-diphenylfluorenyl, 9,9-dinaphthylfluorenyl, 9,9'-spirodifluorenyl, and benzo[a]fluorenyl.

[0090] The C3-C60 heteroaryl (or C6-C50 heteroaryl) mentioned in this invention includes monocyclic heteroaryl and fused-ring heteroaryl, preferably C3-C30 heteroaryl, more preferably C4-C20 heteroaryl, and even more preferably C5-C12 heteroaryl. A monocyclic heteroaryl refers to a molecule containing at least one heteroaryl group. When a molecule contains one heteroaryl group and other groups (such as aryl, heteroaryl, alkyl, etc.), the heteroaryl group and the other groups are independent of each other and connected by a single bond. Examples of monocyclic heteroaryl groups include furanyl, thiophene, pyrrole, and pyridinyl. A fused-ring heteroaryl refers to a molecule containing at least one aromatic heterocycle and an aromatic ring (aromatic heterocycle or aromatic ring), and the two are not independent of each other but share two adjacent atoms fused together. Examples of fused-ring heteroaryl groups include: benzofuranyl, benzothiophenyl, isobenzofuranyl, indolyl, dibenzofuranyl, dibenzothiophenyl, carbazoyl, acridineyl, isobenzofuranyl, isobenzothiophenyl, benzocarbazoyl, azircarbazoyl, phenothiazinyl, phenothiazinyl, 9-phenylcarbazoyl, 9-naphthylcarbazoyl, dibenzocarbazoyl, indolocarbazoyl, etc.

[0091] The aryloxy or heteroaryloxy groups in this invention can be exemplified by the monovalent groups formed by the above-mentioned aryl or heteroaryl groups and oxygen.

[0092] In this invention, arylamino represents a group formed by replacing the hydrogen on an amino group with one or two aryl groups, wherein the linking site of the arylamino can be linked to the aryl group in the arylamino or to the N group in the arylamino, and the exemplary number of carbons and specific groups of the aryl group in the arylamino are the same as described above.

[0093] Examples of C6-C30 arylamino groups mentioned in this invention include phenylamino, methylphenylamino, naphthylamino, anthraceneylamino, phenanthreneamino, and biphenylamino.

[0094] Examples of C3-C30 heteroaryl amino groups mentioned in this invention include pyridinyl amino, pyrimidinyl amino, and dibenzofuranyl amino.

[0095] Unless otherwise specified, the chain alkyl groups mentioned in this invention include straight-chain alkyl groups and branched-chain alkyl groups. Specifically, substituted or unsubstituted C1-C30 chain alkyl groups are preferred, substituted or unsubstituted C1-C16 chain alkyl groups are more preferably substituted or unsubstituted C1-C10 chain alkyl groups. Examples of substituted or unsubstituted C1-C10 chain alkyl groups include: methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, 2-methylbutyl, n-pentyl, sec-pentyl, neopentyl, n-hexyl, neohexyl, n-heptyl, n-octyl, 2-ethylhexyl, etc.

[0096] In this invention, the cycloalkyl group includes monocycloalkyl and polycycloalkyl; wherein, monocycloalkyl refers to an alkyl group containing a single ring structure; polycycloalkyl refers to a structure composed of two or more cycloalkyl groups sharing one or more carbon atoms on a ring; examples of C3-C20 cycloalkyl groups include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, adamantyl, etc.

[0097] In this specification, the substituted or unsubstituted C1-C20 alkoxy group is preferably a substituted or unsubstituted C1-C10 alkoxy group. Examples of C1-C20 alkoxy groups include: methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, sec-butoxy, isobutoxy, tert-butoxy, pentooxy, isopentoxy, hexoxy, heptoxy, octoxy, nonoxy, decoxy, undecoxy, dodecoxy, etc., among which methoxy, ethoxy, n-propoxy, isopropoxy, tert-butoxy, sec-butoxy, isobutoxy, isopentoxy, and more preferably methoxy.

[0098] In this specification, the substituted or unsubstituted C1-C20 silane and the substituted or unsubstituted C1-C10 silane are examples of silanes substituted with groups listed in the above-mentioned C1-C10 chain alkyl groups, specifically including: methylsilane, dimethylsilane, trimethylsilane, ethylsilane, diethylsilane, triethylsilane, tert-butyldimethylsilane, tert-butyldiphenylsilane, etc.

[0099] In this specification, the C2-C20 alkenyl group, preferably C2-C10 alkenyl group, is a hydrocarbon group containing at least one C=C double bond, and includes, but is not limited to: vinyl, propenyl, allyl, butenyl, pentenyl, hexenyl, heptenyl, octenyl, nonenyl, decenyl, butadienyl, pentadienyl, etc.

[0100] It should be noted that while the possible effects of each group / feature have been described separately for ease of explanation in this application, this does not mean that these groups / features act in isolation. In fact, the reason for achieving good performance is essentially the optimized combination of the entire molecule, the result of the synergistic effect between various groups, rather than the effect of a single group.

[0101] This invention also protects a display device, including the organic electroluminescent device described above, wherein the display device includes, but is not limited to, display elements, lighting elements, information tags, electronic artificial skin sheets, or electronic paper.

[0102] The organic electroluminescent device of the present invention includes a light-emitting layer comprising a light-emitting host material, a sensitizer, and a boron-nitrogen narrow-band fluorescent material used as a light-emitting dye. The core structure of this type of narrow-band fluorescent material adopts a compound of boron atoms and heterocyclic rings formed with nitrogen atoms, which has the characteristic of narrow-band emission and a full width at half maximum (FWHM) of the fluorescence spectrum in solution ≤10 nm.

[0103] In the organic electroluminescent device of this invention, when a phosphorus sensitizer is used, after electrical excitation, the device can directly enhance the reverse intersystem crossing rate of the MR-TADF dye by utilizing the external heavy atom effect of the phosphorus sensitizer; or it can achieve the upconversion of the triplet state of the MR-TADF dye to the phosphorus sensitizer triplet state, and the phosphorus sensitizer triplet state further upconverts to the singlet state of the MR-TADF dye, ultimately enhancing the reverse intersystem crossing rate of the MR-TADF dye as well. Therefore, this invention can effectively solve the problem of severe roll-off degradation in MR-TADF devices under high brightness, and effectively enhance the stability of organic electroluminescent devices. Furthermore, in the organic electroluminescent device of the present invention, after being electrically excited, the phosphorus photosensitizer can capture high-energy triplet excitons. Due to its external heavy atom effect, the triplet excitons of the phosphorus photosensitizer can be rapidly transferred to the singlet and triplet states of the MR-TADF dye. Simultaneously, it can directly enhance the reverse intersystem crossing rate of the MR-TADF dye, thereby significantly reducing the concentration of triplet excitons and achieving low efficiency roll-off and long lifetime for the MR-TADF device. Please refer to the schematic diagram of the light-emitting mechanism in the light-emitting layer of the organic electroluminescent device of the present invention. Figure 1 As shown.

[0104] In the organic electroluminescent device of the present invention, when the sensitizer is a phosphorescent sensitizer and the host is a wide-bandgap host, a TADF host, or an excitocomplex host, please refer to the schematic diagram of the light emission mechanism in the light-emitting layer of the organic electroluminescent device of the present invention. Figure 1 As shown. When the sensitizer is TADF sensitizer and the host is a wide-bandgap host, TADE host, or excitocomplex host, please refer to the schematic diagram of the light emission mechanism in the light-emitting layer of the organic electroluminescent device of the present invention. Figure 2As shown. When no sensitizer is used in the light-emitting layer, and the host is a TADF host or an excimer complex host, please refer to the schematic diagram of the light-emitting mechanism in the light-emitting layer of the organic electroluminescent device of the present invention. Figure 3 As shown. Attached Figure Description

[0105] Figure 1 This is a schematic diagram of the light emission mechanism when a phosphorus photosensitizer is used in the light-emitting layer of the organic electroluminescent device of the present invention. In the diagram, FET stands for Forster energy transfer, DET stands for Dexter energy transfer, ISC stands for intersystem crossing, and RISC stands for reverse intersystem crossing.

[0106] Figure 2 This is a schematic diagram of the light emission mechanism when the TADF sensitizer is used in the light-emitting layer of the organic electroluminescent device of the present invention, wherein FET stands for Forster energy transfer, DET stands for Dexter energy transfer, ISC stands for intersystem crossing, and RISC stands for reverse intersystem crossing.

[0107] Figure 3 This is a schematic diagram of the light emission mechanism in an existing organic electroluminescent device where no sensitizer is used in the light-emitting layer.

[0108] Figure 4 This is a schematic diagram of the structure of the organic electroluminescent device prepared in the embodiments of the present invention.

[0109] like Figure 4 As shown, the organic electroluminescent device of the present invention includes an anode 2, a hole transport region 3, an organic light-emitting layer 4, an electron transport region 5, and a cathode 6 sequentially deposited on a substrate 1. Detailed Implementation

[0110] 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.

[0111] The method for synthesizing the boron-nitrogen heterocyclic narrow-band fluorescent material with the structure of formula (1) used as the luminescent dye in the luminescent layer of the organic electroluminescent device of the present invention is as follows:

[0112] Synthesis Example 1:

[0113]

[0114] Synthesis of Compound 2: 455 mg of N-bromosuccinimide (1.71 mmol) and 304 mg of aluminum tribromide (1.71 mmol) were weighed and added to dichloromethane (20 mL). After stirring at 0 °C for 30 minutes, a dichloromethane solution of Compound 1 (100 mg, 0.77 mmol) (20 mL) was added. After the addition was complete, the mixture was stirred overnight at 25 °C. After the reaction was complete, the mixture was filtered, and the solvent was removed under reduced pressure. The solution was then purified by column chromatography (eluent: petroleum ether: dichloromethane = 10:1) to give white solid 2 (117 mg, 53%). 1 ¹H NMR (400MHz, CDCl₃, 297K, ppm) δ 8.07 (d, J = 7.2Hz, 2H), 7.78 (d, J = 6.8Hz, 2H), 6.60 (t, J = 7.2Hz, 2H). MS (EI) Theoretical value: C₈H₆BBr₂N: 284.90; Experimental value: 284.89 [M] + .

[0115]

[0116] Synthesis of compound 3: 1,3-Butadiene (1.05 mL, 2.09 mmol, 2.0 M in THF) and a solution of 9-boronbicyclo[3.3.1]nonane (9-BBN) (8.37 mL, 4.19 mmol, 0.5 M in THF) were added to a Shrek flask and stirred overnight at 25 °C. Compound 2 (500 mg, 1.74 mmol), palladium acetate (39.2 mg, 0.175 mmol), 2-dicyclohexylphosphine-2',6'-dimethoxybiphenyl (SPhos) (143 mg, 0.348 mmol), and potassium phosphate (1.11 g, 5.23 mmol) were added to another Shrek flask. The mixture was purged three times under argon protection. Tetrahydrofuran and water were added, followed by the solution that had been stirred overnight at 25 °C. The mixture was stirred and refluxed at 70 °C for 23 hours. After the reaction was complete, the mixture was extracted with water and dichloromethane. The organic layers were combined, dried over anhydrous magnesium sulfate, filtered, and evaporated to dryness. The solution was then separated by column chromatography (eluent: petroleum ether) to obtain a pale yellow liquid 3 (260 mg, 82%). 1 ¹H NMR (400MHz, CDCl₃, 297K, ppm) δ 7.66 (d, J = 6.8Hz, 2H), 7.31 (d, J = 6.4Hz, 2H), 6.57 (t, J = 6.8Hz, 2H), 2.95 (t, J = 5.6Hz, 4H), 1.94–1.90 (m, 4H). MS (EI) theoretical value: C 12 H 14 BN: 183.12; Experimental value: 183.12 [M] + .

[0117]

[0118] Synthesis of compound 4: Compound 3 (824 mg, 4.50 mmol) was weighed, purged three times under argon protection, and tetrahydrofuran (25 mL) was added. Tert-butyllithium (3.80 mL, 4.95 mmol, 1.3 M in pentane) was added dropwise at -78 °C. After stirring at 25 °C for 1 hour, 1,2-dibromoethane (1.27 g, 6.75 mmol) was added, and the mixture was stirred at 25 °C overnight. After the reaction was complete, the mixture was extracted with sodium sulfite solution and dichloromethane. The organic layers were combined, dried over anhydrous magnesium sulfate, filtered, and evaporated to dryness. The mixture was then separated by column chromatography (eluent: petroleum ether) to give a pale yellow liquid 4 (566 mg, 48%). 1 ¹H NMR (400MHz, CDCl₃, 297K, ppm) δ 8.32 (d, J = 7.2Hz, 1H), 7.35 (d, J = 6.4Hz, 1H), 7.18 (d, J = 7.2Hz, 1H), 6.98 (d, J = 6.8Hz, 1H), 6.70 (t, J = 6.8Hz, 1H), 2.98–2.90 (m, 4H), 1.92–1.88 (m, 4H). MS (EI) theoretical value: C 12 H 13 BBrN: 261.03; Experimental value: 261.03 [M] + .

[0119]

[0120] Synthesis of compound 5: Compound 4 (292 mg, 1.12 mmol), bis(triphenylphosphine)palladium dichloride (39.4 mg, 0.06 mmol), and cuprous iodide (15.0 mg, 0.08 mmol) were weighed, purged three times under argon protection, tetrahydrofuran (2 mL) was added, followed by the injection of triethylamine (2 mL) and trimethylsilylacetylene (165 mg, 1.69 mmol). The mixture was stirred and refluxed at 70 °C for 10 hours. After the reaction was complete, the mixture was extracted with water and dichloromethane. The organic layers were combined, dried over anhydrous magnesium sulfate, filtered, and evaporated to dryness. The mixture was then separated by column chromatography (eluent: petroleum ether) to obtain a pale yellow liquid 5 (307 mg, 98%). 1 ¹H NMR (400MHz, CDCl₃, 297K, ppm) δ 8.48 (d, J = 6.8Hz, 1H), 7.35 (dd, J = 6.8Hz, 1.2Hz, 1H), 7.24 (dd, J = 6.8Hz, 1.2Hz, 1H), 7.00 (d, J = 6.8Hz, 1H), 6.67 (t, J = 6.8Hz, 1H), 2.97–2.93 (m, 4H), 1.91–1.88 (m, 4H). MS (EI) theoretical value: C 17H 22 BNSi: 279.16; Experimental value: 279.16 [M] + .

[0121]

[0122] Synthesis of compound 6: Compound 5 (307 mg, 1.10 mmol) and potassium carbonate (608 mg, 4.40 mmol) were weighed, and dichloromethane (7.3 mL) and methanol (3.6 mL) were added. The mixture was stirred at 25 °C for 3 hours. After the reaction was completed, the mixture was filtered, extracted with water and dichloromethane, and the organic layers were combined and dried with anhydrous magnesium sulfate. The mixture was filtered, evaporated to dryness, and separated by column chromatography (eluent: petroleum ether) to obtain a pale yellow liquid 6 (188 mg, 82%). 1 H NMR (400MHz, CDCl3, 297K, ppm) δ8.54(dd,J=7.2Hz,2.0Hz,1H),7.40(d,J=6.4Hz,1H),7.30(d,J=6.8Hz,1H),7.07(dd,J =6.8Hz, 2.0Hz, 1H), 6.72 (td, J = 6.8Hz, 2.0Hz, 1H), 3.64 (s, 1H), 3.00 (t, J = 3.2Hz, 4H), 1.99–1.92 (m, 4H). MS (EI) theoretical value: C 14 H 14 BN: 207.12; Experimental value: 207.12 [M] + .

[0123]

[0124] Synthesis of compound 7: Compound 6 (188 mg, 0.91 mmol) and platinum dichloride (24.2 mg, 0.09 mmol) were weighed, and the mixture was purged three times under argon protection. 1,2-Dichloroethane (10 mL) was added, and the mixture was stirred and refluxed at 125 °C for 16 hours. After the reaction was completed, water and dichloromethane were added for extraction. The organic layers were combined, dried with anhydrous magnesium sulfate, filtered, and evaporated to dryness. Column chromatography (eluent: petroleum ether) was performed to obtain a pale yellow liquid 7 (53 mg, 28%). 1 ¹H NMR (400MHz, CDCl₃, 297K, ppm) δ 7.92 (d, J = 7.2Hz, 2H), 7.46 (d, J = 7.2Hz, 2H), 7.43 (s, 2H), 3.33–3.30 (m, 4H), 2.21–2.14 (m, 4H). MS (EI) theoretical value: C 14 H 14 BN: 207.12; Experimental value: 207.12 [M] + .

[0125]

[0126] Synthesis of compound E-1: Compound 7 (53 mg, 0.28 mmol) and 2,3-dichloro-5,6-dicyanobenzoquinone (DDQ) (160 mg, 0.71 mmol) were weighed and added toluene. The mixture was heated and stirred at 60 °C for 9 hours. After the reaction was completed, water and dichloromethane were added for extraction. The organic layers were combined and dried with anhydrous magnesium sulfate. The mixture was filtered, evaporated to dryness, and separated by column chromatography (eluent: petroleum ether) to obtain red solid E-1 (28 mg, 54%). 1 ¹H NMR (400MHz, CDCl₃, 297K, ppm) δ 9.14–9.09 (m, 2H), 9.02 (d, J = 8.0Hz, 2H), 8.80 (d, J = 8.0Hz, 2H), 8.37 (s, 2H), 8.08–8.02 (m, 2H). MS (EI) theoretical value: C 14 H 10 BN: 203.09; Experimental value: 203.09 [M] + .

[0127] The following describes in detail the synthetic method of borazine APD derivatives with examples. The method consists of two steps: (1) achieving five-membered ring closure through transition metal catalysis and the corresponding alkyne reaction; (2) preparing substituted borazine APD derivatives through dehydrogenation aromatization reaction.

[0128] Synthesis Example 2:

[0129]

[0130] Synthesis of Compound 8: Compound 4 (130 mg, 0.50 mmol), (triphenylsilyl)acetylene (169 mg, 0.60 mmol), bis(triphenylphosphine)palladium dichloride (17.4 mg, 0.02 mmol), and triphenylphosphine (30.0 mg, 0.11 mmol) were weighed out, purged three times, and protected with argon. Benzene (1 mL) and xylene (1 mL) were added, followed by the injection of triethylamine (0.5 mL). The mixture was heated and stirred at 120 °C for 24 hours. After the reaction was complete, the mixture was extracted with water and dichloromethane. The organic layers were combined, dried over anhydrous magnesium sulfate, filtered, and evaporated to dryness. The mixture was then separated by column chromatography (eluent: petroleum ether) to obtain the target compound 8 (180 mg, 78%) as a yellow solid. 1H NMR (400MHz, CDCl3, 297K, ppm) δ8.44(d,J=7.2Hz,1H),7.65–7.60(m,6H),7.56–7.51(m,3H),7.30–7.23(m,6H),7.18(m,1 H),7.11(d,J=6.8Hz,1H),6.98(d,J=6.8Hz,1H),6.49–6.46(m,1H),2.83–2.76(m,4H),1.77–1.71(m,4H).MS (MALDI) theoretical value: C 32 H 28 BNSi: 465.21; Experimental value: 465.21 [M] + .

[0131] Synthesis of compound E-508: Compound 8 (186 mg, 0.40 mmol) and 2,3-dichloro-5,6-dicyanobenzoquinone (DDQ) (100 mg, 0.440 mmol) were weighed and added toluene (15 mL). The mixture was heated and stirred at 60 °C for 13 hours. After the reaction was completed, the mixture was extracted with water and dichloromethane. The organic layers were combined and dried with anhydrous magnesium sulfate. The mixture was filtered, evaporated to dryness, and separated by column chromatography (eluent was petroleum ether). The red solid E-508 (60 mg, 70%) was obtained by recrystallization from dichloromethane / methanol. 1 ¹H NMR (400MHz, CDCl₃, 297K, ppm) δ 9.12–9.05 (m, 2H), 8.98 (d, J = 8.4Hz, 1H), 8.84 (d, J = 8.4Hz, 1H), 8.73 (d, J = 8.4Hz, 1H), 8.41 (s, 1H), 8.38 (d, J = 8.4Hz, 1H), 8.08–8.00 (m, 2H), 7.75–7.72 (m, 6H), 7.50–7.46 (m, 3H), 7.42–7.38 (m, 6H). HRMS (MALDI) theoretical values: C 32 H 24 BNSi: 461.18; Experimental value: 461.18 [M] + .

[0132] Synthesis Example 3:

[0133]

[0134] Synthesis of Compound 8-1: This example is basically the same as Synthesis Example 2, except that (triphenylsilyl)acetylene needs to be replaced with an equal amount of 4-triphenylsilyl-1-butyne. The final product was the target compound, white solid 8-1 (98 mg, 40%). MS (MALDI) theoretical value: 493.24; experimental value: 493.24 [M]. + .

[0135] Synthesis of compound E-62: This example is basically the same as synthesis example 2, except that 8 needs to be replaced with an equimolar amount of 9-1. The final product was the target compound, a red solid 9-1 (117 mg, 60%). MS (MALDI) theoretical value: 489.21; experimental value: 489.21 [M]. + .

[0136] Synthesis Example 4:

[0137]

[0138] Synthesis of Compound 8-2: This example is basically the same as Synthesis Example 2, except that (triphenylsilyl)acetylene needs to be replaced with an equimolar amount of 3-triphenylmethyl-1-butyne. The final product was the target compound, a white solid 8-2 (105 mg, 45%). MS (MALDI) theoretical value: 463.25; experimental value: 463.25 [M]. + .

[0139] Synthesis of compound E-70: This example is basically the same as synthesis example 2, except that 8 needs to be replaced with an equimolar amount of 8-2. The final product was the target compound, red solid E-70 (110 mg, 60%). MS (MALDI) theoretical value: 459.22; experimental value: 459.21 [M]. + .

[0140] Synthesis Example 5:

[0141]

[0142] Synthesis of Compound 8-3: This example is basically the same as Synthesis Example 2, except that (triphenylsilyl)acetylene needs to be replaced with an equal amount of (tert-butyldiphenylsilyl)acetylene. The final product was the target compound, a white solid 8-3 (89 mg, 40%). MS (MALDI) theoretical value: 445.24; experimental value: 445.23 [M]. + .

[0143] Synthesis of compound E-58: This example is basically the same as synthesis example 2, except that 8 needs to be replaced with an equimolar amount of 8-3. The final product was the target compound, red solid E-58 (97 mg, 55%). MS (MALDI) theoretical value: 441.21; experimental value: 441.21 [M]. + .

[0144] Synthesis Example 6:

[0145]

[0146] Synthesis of Compound 8-4: This example is basically the same as Synthesis Example 2, except that (triphenylsilyl)acetylene needs to be replaced with an equal amount of (tri-tert-butylphenylsilyl)acetylene. The final product was the target compound, a white solid 8-4 (158 mg, 50%). MS (MALDI) theoretical value: 633.40; experimental value: 633.39 [M]. + .

[0147] Synthesis of compound E-518: This example is basically the same as synthesis example 2, except that 8 needs to be replaced with an equimolar amount of 8-4. The final product was the target compound, red solid E-518 (151 mg, 60%). MS (MALDI) theoretical value: 629.36; experimental value: 629.36 [M]. + .

[0148] Synthesis Example 7:

[0149]

[0150] Synthesis of Compound 8-5: This example is basically the same as Synthesis Example 2, except that (triphenylsilyl)acetylene is replaced with an equimolar amount of tris([1,1'-biphenyl]-4-yl)(acetylenyl)silane. The final product was the target compound, a white solid 8-5 (208 mg, 60%). MS (MALDI) theoretical value: 693.30; experimental value: 693.30 [M]. + .

[0151] Synthesis of compound E-545: This example is basically the same as synthesis example 2, except that 8 needs to be replaced with an equimolar amount of 8-5. The final product was the target compound, red solid E-545 (165 mg, 60%). MS (MALDI) theoretical value: 689.27; experimental value: 689.27 [M]. + .

[0152] Synthesis Example 8:

[0153]

[0154] Synthesis of Compound 8-6: This example is basically the same as Synthesis Example 2, except that (triphenylsilyl)acetylene is replaced with an equimolar amount of ethynyltris(naphth-1-yl)silane. The final product was the target compound, white solid 8-6 (184 mg, 60%). MS (MALDI) theoretical value: 615.26; experimental value: 615.25 [M]. + .

[0155] Synthesis of compound E-529: This example is basically the same as synthesis example 2, except that 8 needs to be replaced with an equimolar amount of 8-6. The final product was the target compound, red solid E-529 (147 mg, 60%). MS (MALDI) theoretical value: 611.22; experimental value: 611.22 [M]. + .

[0156] Synthesis Example 9:

[0157]

[0158] Synthesis of Compound 8-7: This example is basically the same as Synthesis Example 2, except that (triphenylsilyl)acetylene needs to be replaced with an equimolar amount of tris(3,5-di-tert-butylphenyl)acetylenylsilane. The final product was the target compound, a white solid 8-7 (248 mg, 62%). MS (MALDI) theoretical value: 801.58; experimental value: 801.58 [M]. + .

[0159] Synthesis of compound E-520: This example is basically the same as synthesis example 2, except that 8 needs to be replaced with an equimolar amount of 8-7. The final product was the target compound, red solid E-520 (175 mg, 55%). MS (MALDI) theoretical value: 797.55; experimental value: 797.55 [M]. + .

[0160] Synthesis Example 10:

[0161]

[0162] Synthesis of Compound 10: Compound 4 (40.0 mg, 0.15 mmol), diphenylacetylene (32.0 mg, 0.18 mmol), tris(dibenzylacetone)dipalladium-chloroform adduct (15.8 mg, 0.02 mmol), tris(o-methylphenyl)phosphine (6.97 mg, 0.02 mmol), potassium acetate (44.9 mg, 0.46 mmol), and lithium chloride (6.47 mg, 0.15 mmol) were weighed out, purged three times, and protected with argon. Toluene (2 mL) and N,N-dimethylformamide (2 mL) were added, and the mixture was heated and stirred at 120 °C. After the reaction was complete, the mixture was extracted with water and dichloromethane. The organic layers were combined, dried over anhydrous magnesium sulfate, filtered, and evaporated to dryness. The mixture was then separated by column chromatography (eluent: petroleum ether) to give a yellow solid 10 (22 mg, 40%). 1 ¹H NMR (400MHz, CDCl₃, 297K, ppm) δ 7.95 (d, J = 7.2Hz, 2H), 7.49 (d, J = 7.2Hz, 2H), 7.46–7.43 (m, 4H), 7.42–7.35 (m, 6H), 3.35–3.30 (m, 4H), 2.21–2.17 (m, 4H). MS (MALDI) theoretical value: C 26 H 22 BN: 359.18; Experimental value: 359.18 [M] + .

[0163] Synthesis of compound E-201: Compound 10 (22 mg, 0.06 mmol) and 2,3-dichloro-5,6-dicyanobenzoquinone (DDQ) (30 mg, 0.13 mmol) were weighed and added toluene (2 mL). The mixture was heated and stirred at 60 °C for 18 hours. After the reaction was completed, the mixture was extracted with water and dichloromethane. The organic layers were combined and dried with anhydrous magnesium sulfate. The mixture was filtered, evaporated to dryness, and separated by column chromatography (eluent was petroleum ether). The target compound E-201 (10 mg, 47%) was obtained by recrystallization from dichloromethane / methanol. 1 ¹H NMR (400MHz, CDCl₃, 297K, ppm) δ 9.08–9.05 (m, 2H), 9.02 (d, J = 8.4Hz, 2H), 8.01 (d, J = 8.4Hz, 2H), 8.05–7.99 (m, 2H), 7.71–7.68 (m, 4H), 7.54–7.50 (m, 4H), 7.47–7.42 (m, 2H). MS (MALDI) theoretical value: C 26 H 22 BN: 355.15; Experimental value: 355.15 [M] + .

[0164] Synthesis Example 11:

[0165]

[0166] Synthesis of Compound 10-1: This example is basically the same as the synthesis example 10, except that the diphenylacetylene is replaced with an equal amount of 4-tert-butylphenylacetylene. The final product was the target compound, a white solid 10-1 (24 mg, 35%). MS (MALDI) theoretical value: 471.31; experimental value: 471.30 [M]. + .

[0167] Synthesis of compound E-206: This example is basically the same as synthesis example 10, except that 10 is replaced with an equimolar amount of 10⁻¹. The final product was the target compound, red solid E-206 (17 mg, 62%). MS (MALDI) theoretical value: 467.28; experimental value: 467.27 [M]. + .

[0168] Synthesis Example 12:

[0169]

[0170] Synthesis of Compound 10-2: This example is basically the same as the synthesis example 10, except that in this example, diphenylacetylene is replaced with an equimolar amount of (4-tert-butylphenyl)acetylenylbenzene. The final product is the target compound, a white solid 10-2 (28 mg, 45%). MS (MALDI) theoretical value: 415.25; experimental value: 415.25 [M]. + .

[0171] Synthesis of compound E-361: This example is basically the same as synthesis example 10, except that 10 is replaced with an equimolar amount of 10⁻². The final product was the target compound, red solid E-361 (12 mg, 50%). MS (MALDI) theoretical value: 411.22; experimental value: 411.22 [M]. + .

[0172] Synthesis Example 13:

[0173]

[0174] Synthesis of Compound 10-3: This example is basically the same as the synthesis example 10, except that in this example, diphenylacetylene is replaced with an equal amount of phenylacetynyltrimethylsilane. The final product was the target compound, a white solid 10-3 (26 mg, 50%). MS (MALDI) theoretical value: 355.19; experimental value: 355.19 [M]. + .

[0175] Synthesis of compound E-345: This example is basically the same as synthesis example 10, except that 10 is replaced with an equimolar amount of 10⁻³. The final product was the target compound, red solid E-345 (12 mg, 60%). MS (MALDI) theoretical value: 351.16; experimental value: 351.16 [M]. + .

[0176] The preparation of boron-aza narrow-spectrum molecules with other substituents simply requires replacing the substituents of the reactants with the corresponding substituents, which will not be elaborated here.

[0177] Examples of organic electroluminescence preparation of the present invention:

[0178] In the organic electroluminescent device of the present invention, the substrate can be made of glass or polymer material with excellent mechanical strength, thermal stability, water resistance, and transparency. Furthermore, the substrate used as a display can also contain thin-film transistors (TFTs).

[0179] The anode can be formed by sputtering or depositing anode material on a substrate. The anode material can be any combination of transparent conductive oxide materials such as indium tin oxide (ITO), indium zinc oxide (IZO), tin dioxide (SnO2), and zinc oxide (ZnO). The cathode can be any combination of metals or alloys such as magnesium (Mg), silver (Ag), aluminum (Al), aluminum-lithium (Al-Li), calcium (Ca), magnesium-indium (Mg-In), and magnesium-silver (Mg-Ag).

[0180] The hole transport region, the light-emitting layer, the electron transport region, and the organic material layer of the cathode can be sequentially prepared on the anode using methods such as vacuum thermal evaporation, spin coating, and printing. The compounds used as the organic material layer can be small organic molecules, large organic molecules, polymers, or combinations thereof.

[0181] Combination Figure 4 The hole transport region 3, electron transport region 5, and cathode 6 of the present invention will be described below. The hole transport region 3 is located between the anode 2 and the organic light-emitting layer 4. The hole transport region 3 can be a single-layer hole transport layer (HTL), including a single-layer hole transport layer containing only one compound and a single-layer hole transport layer containing multiple compounds. The hole transport region 3 can also be a multilayer structure including at least one of a hole injection layer (HIL), a hole transport layer (HTL), and an electron blocking layer (EBL).

[0182] The material of hole transport region 3 (including HIL, HTL and EBL) may be selected from, but is not limited to, phthalocyanine derivatives such as CuPc, conductive polymers or polymers containing conductive dopants such as polyphenylene oxide, polyaniline / dodecylbenzenesulfonic acid (Pani / DBSA), poly(3,4-ethylenedioxythiophene) / poly(4-styrenesulfonate) (PEDOT / PSS), polyaniline / camphorsulfonic acid (Pani / CSA), polyaniline / poly(4-styrenesulfonate) (Pani / PSS), and aromatic amine derivatives.

[0183] The aromatic amine derivatives are compounds shown as HT-1 to HT-34 below. If the material of the hole transport region 3 is an aromatic amine derivative, it can be one or more of the compounds shown as HT-1 to HT-34.

[0184]

[0185]

[0186] The hole injection layer is located between the anode 2 and the hole transport layer. The hole injection layer can be a single compound material or a combination of multiple compounds. For example, the hole injection layer can be one or more compounds of HT-1 to HT-34 mentioned above, or one or more compounds of HI1 to HI3 mentioned below; it can also be one or more compounds of HT-1 to HT-34 doped with one or more compounds of HI1 to HI3 mentioned below.

[0187]

[0188] The electron transport region 5 can be a single-layer electron transport layer (ETL), including a single-layer electron transport layer containing only one compound and a single-layer electron transport layer containing multiple compounds. The electron transport region 5 can also be a multilayer structure including at least one of an electron injection layer (EIL), an electron transport layer (ETL), and a hole blocking layer (HBL).

[0189] In one aspect of the present invention, the electron transport layer material may be selected from, but not limited to, one or more combinations of ET-1 to ET-57 listed below.

[0190]

[0191]

[0192]

[0193] The structure of the light-emitting device may also include an electron injection layer located between the electron transport layer and the cathode 6. The electron injection layer material includes, but is not limited to, one or more combinations of the following: LiQ, LiF, NaCl, CsF, Li2O, Cs2CO3, BaO, Na, Li, Ca.

[0194] The thickness of each of the above layers can be the conventional thickness of such layers in this field.

[0195] The following is a detailed description of the light-emitting layer. The organic light-emitting layer 4 is formed by co-evaporation of the host material, a narrow-band boron-nitrogen heterocyclic fluorescent dye, and a phosphorus photosensitizer.

[0196] The organic electroluminescent device of the present invention will be further described below through specific embodiments.

[0197] The method for preparing the organic electroluminescent device of the present invention includes the following steps:

[0198] 1. The glass plate coated with the anodic material is ultrasonically treated in a commercial cleaning agent, rinsed in deionized water, ultrasonically degreased in a mixture of acetone and ethanol, baked in a clean environment until all moisture is removed, cleaned with ultraviolet light and ozone, and bombarded with a low-energy cation beam.

[0199] 2. Place the glass plate with the anode inside the vacuum chamber and evacuate to a vacuum level of 1×10⁻⁶. -5 ~9×10 -3 Pa, a hole injection layer is vacuum-deposited on the above-mentioned anolyte film at a deposition rate of 0.1-0.5 nm / s;

[0200] 3. A hole transport layer is vacuum-deposited on top of the hole injection layer at a deposition rate of 0.1-0.5 nm / s.

[0201] 4. A light-emitting layer for the device is vacuum-deposited on top of the hole transport layer. The light-emitting layer includes a host material, a narrow-band boron-nitrogen heterocyclic fluorescent dye, and a sensitizer material. A multi-source co-evaporation method is used to adjust the deposition rate so that the dye reaches a preset doping ratio.

[0202] 5. The electron transport layer material of the device is vacuum-deposited on top of the organic light-emitting layer at a deposition rate of 0.1-0.5 nm / s;

[0203] 6. A LiF layer is vacuum-deposited at 0.1-0.5 nm / s as the electron injection layer on the electron transport layer, and an Al layer is vacuum-deposited at 0.5-1 nm / s as the cathode of the device.

[0204] The structural formulas of some organic materials used in the embodiments of this invention are as follows:

[0205]

[0206] Device Example D1-1

[0207] The device structure of this embodiment is shown below:

[0208] ITO / HI-2(10nm) / HT-27(40nm) / W-7:10wt%T-19:1wt%E-1(30nm) / ET-53(30nm) / LiF(0.5nm) / Al(150nm)

[0209] The anode is ITO; the hole injection layer is made of HI-2, with a total thickness of 5-30 nm, and 10 nm in this embodiment; the hole transport layer is made of HI-27, with a total thickness of 5-500 nm, and 40 nm in this embodiment; the main material of the organic light-emitting layer is W-7, the TADF sensitizer is T-5 with a doping concentration of 10 wt%, the dye is E-1, a boron-nitrogen heterocyclic narrow-band fluorescent material with a doping concentration of 1 wt%, and the thickness of the organic light-emitting layer is generally 1-200 nm, and 30 nm in this embodiment; the electron transport layer is made of ET-53, with a thickness of 5-300 nm, and 30 nm in this embodiment; the electron injection layer and cathode materials are LiF (0.5 nm) and aluminum (150 nm), with LiF vacuum-deposited at 0.5 nm / s as the electron injection layer and Al layer vacuum-deposited at 0.5-1 nm / s as the cathode of the device.

[0210] Following the preparation steps and testing methods of the above embodiment D1-1, the device embodiments D1-1 to D1-41 of the present invention were completed. The specific design scheme of the light-emitting layer is detailed in the following embodiments and Table 1.

[0211] Example D1-2

[0212] The device structure of this embodiment is shown below:

[0213] The device meanings of ITO / HI-2(10nm) / HT-27(40nm) / W-7:10wt%T-5:1wt%E-1(30nm) / ET-53(30nm) / LiF(0.5nm) / Al(150nm) are roughly the same as those of Example D1-1, the only difference being the different TADF sensitizer.

[0214] Examples D1-3

[0215] The device structure of this embodiment is shown below:

[0216] The device meanings of ITO / HI-2(10nm) / HT-27(40nm) / T-26:10wt%T-19:1wt%E-1(30nm) / ET-53(30nm) / LiF(0.5nm) / Al(150nm) are roughly the same as those of Example D1-1, the only difference being the different main materials.

[0217] Examples D1-4

[0218] The device structure of this embodiment is shown below:

[0219] The device meanings of ITO / HI-2(10nm) / HT-27(40nm) / T-8:10wt%T-19:1wt%E-1(30nm) / ET-53(30nm) / LiF(0.5nm) / Al(150nm) are roughly the same as those of Example D1-1, the only difference being the different main materials.

[0220] Examples D1-5

[0221] The device structure of this embodiment is shown below:

[0222] The device meanings of ITO / HI-2(10nm) / HT-27(40nm) / W-15:10wt%T-19:1wt%E-1(30nm) / ET-53(30nm) / LiF(0.5nm) / Al(150nm) are roughly the same as those of Example D1-1, the only difference being the different main materials.

[0223] Examples D1-6

[0224] The device structure of this embodiment is shown below:

[0225] The device meanings of ITO / HI-2(10nm) / HT-27(40nm) / W-7:5wt%T-19:1wt%E-1(30nm) / ET-53(30nm) / LiF(0.5nm) / Al(150nm) are roughly the same as those of Example D1-1, the only difference being the different concentrations of TADF sensitizer.

[0226] Examples D1-7

[0227] The device structure of this embodiment is shown below:

[0228] The device meanings of ITO / HI-2(10nm) / HT-27(40nm) / W-7:10wt%T-19:5wt%E-1(30nm) / ET-53(30nm) / LiF(0.5nm) / Al(150nm) are roughly the same as those of Example D1-1, the only difference being the different concentrations of the resonant TADF dye.

[0229] Examples D1-8

[0230] The device structure of this embodiment is shown below:

[0231] The device meanings of ITO / HI-2(10nm) / HT-27(40nm) / D-1:A-3:10wt%T-19:1wt%E-1(30nm) / ET-53(30nm) / LiF(0.5nm) / Al(150nm) are roughly the same as those of Example D1-1, the only difference being the different main materials.

[0232] Examples D1-9

[0233] The device structure of this embodiment is shown below:

[0234] The device meanings of ITO / HI-2(10nm) / HT-27(40nm) / D-5:A-5:10wt%T-19:1wt%E-1(30nm) / ET-53(30nm) / LiF(0.5nm) / Al(150nm) are roughly the same as those of Example D1-1, the only difference being the different main materials.

[0235] Examples D1-10

[0236] The device structure of this embodiment is shown below:

[0237] The device meanings of ITO / HI-2(10nm) / HT-27(40nm) / W-7:10wt%T-19:1wt%E-58(30nm) / ET-53(30nm) / LiF(0.5nm) / Al(150nm) are roughly the same as those of Example D1-1, the only difference being the different resonant TADF dyes.

[0238] Example D1-11

[0239] The device structure of this embodiment is shown below:

[0240] The device meanings of ITO / HI-2(10nm) / HT-27(40nm) / T-26:10wt%T-19:1wt%E-58(30nm) / ET-53(30nm) / LiF(0.5nm) / Al(150nm) are roughly the same as those of Examples D1-10, the only difference being the different main materials.

[0241] Examples D1-12

[0242] The device structure of this embodiment is shown below:

[0243] The device meanings of ITO / HI-2(10nm) / HT-27(40nm) / D-1:A-3:10wt%T-19:1wt%E-58(30nm) / ET-53(30nm) / LiF(0.5nm) / Al(150nm) are roughly the same as those of Examples D1-10, the only difference being the different main materials.

[0244] Examples D1-13

[0245] The device structure of this embodiment is shown below:

[0246] The device meanings of ITO / HI-2(10nm) / HT-27(40nm) / W-7:10wt%T-19:1wt%E-62(30nm) / ET-53(30nm) / LiF(0.5nm) / Al(150nm) are roughly the same as those of Example D1-1, the only difference being the different resonant TADF dyes.

[0247] Examples D1-14

[0248] The device structure of this embodiment is shown below:

[0249] The device meanings of ITO / HI-2(10nm) / HT-27(40nm) / T-26:10wt%T-19:1wt%E-62(30nm) / ET-53(30nm) / LiF(0.5nm) / Al(150nm) are roughly the same as those of Examples D1-13, the only difference being the different main materials.

[0250] Examples D1-15

[0251] The device structure of this embodiment is shown below:

[0252] The device meanings of ITO / HI-2(10nm) / HT-27(40nm) / D-1:A-3:10wt%T-19:1wt%E-62(30nm) / ET-53(30nm) / LiF(0.5nm) / Al(150nm) are roughly the same as those of Examples D1-13, the only difference being the different resonant TADF dyes.

[0253] Examples D1-16

[0254] The device structure of this embodiment is shown below:

[0255] The device meanings of ITO / HI-2(10nm) / HT-27(40nm) / W-7:10wt%T-19:1wt%E-70(30nm) / ET-53(30nm) / LiF(0.5nm) / Al(150nm) are roughly the same as those of Example D1-1, the only difference being the different resonant TADF dyes.

[0256] Examples D1-17

[0257] The device structure of this embodiment is shown below:

[0258] The device meanings of ITO / HI-2(10nm) / HT-27(40nm) / T-26:10wt%T-19:1wt%E-70(30nm) / ET-53(30nm) / LiF(0.5nm) / Al(150nm) are roughly the same as those of Examples D1-16, the only difference being the different main materials.

[0259] Examples D1-18

[0260] The device structure of this embodiment is shown below:

[0261] The device meanings of ITO / HI-2(10nm) / HT-27(40nm) / D-1:A-3:10wt%T-19:1wt%E-70(30nm) / ET-53(30nm) / LiF(0.5nm) / Al(150nm) are roughly the same as those of Examples D1-16, the only difference being the different main materials.

[0262] Examples D1-19

[0263] The device structure of this embodiment is shown below:

[0264] The device meanings of ITO / HI-2(10nm) / HT-27(40nm) / W-7:10wt%T-19:1wt%E-201(30nm) / ET-53(30nm) / LiF(0.5nm) / Al(150nm) are roughly the same as those of Example D1-1, the only difference being the different resonant TADF dyes.

[0265] Examples D1-20

[0266] The device structure of this embodiment is shown below:

[0267] The device meanings of ITO / HI-2(10nm) / HT-27(40nm) / T-26:10wt%T-19:1wt%E-201(30nm) / ET-53(30nm) / LiF(0.5nm) / Al(150nm) are roughly the same as those of Examples D1-19, the only difference being the different main materials.

[0268] Examples D1-21

[0269] The device structure of this embodiment is shown below:

[0270] The device meanings of ITO / HI-2(10nm) / HT-27(40nm) / D-1:A-3:10wt%T-19:1wt%E-201(30nm) / ET-53(30nm) / LiF(0.5nm) / Al(150nm) are roughly the same as those of Examples D1-6, the only difference being the different main materials.

[0271] Examples D1-22

[0272] The device structure of this embodiment is shown below:

[0273] The device meanings of ITO / HI-2(10nm) / HT-27(40nm) / W-7:10wt%T-19:1wt%E-206(30nm) / ET-53(30nm) / LiF(0.5nm) / Al(150nm) are roughly the same as those of Example D1-1, the only difference being the different resonant TADF dyes.

[0274] Examples D1-23

[0275] The device structure of this embodiment is shown below:

[0276] The device meanings of ITO / HI-2(10nm) / HT-27(40nm) / T-26:10wt%T-19:1wt%E-206(30nm) / ET-53(30nm) / LiF(0.5nm) / Al(150nm) are roughly the same as those of Examples D1-22, the only difference being the different main materials.

[0277] Examples D1-24

[0278] The device structure of this embodiment is shown below:

[0279] The device meanings of ITO / HI-2(10nm) / HT-27(40nm) / D-1:A-3:10wt%T-19:1wt%E-206(30nm) / ET-53(30nm) / LiF(0.5nm) / Al(150nm) are roughly the same as those of Examples D1-22, the only difference being the different main materials.

[0280] Examples D1-25

[0281] The device meanings of ITO / HI-2(10nm) / HT-27(40nm) / W-7:10wt%T-19:1wt%E-345(30nm) / ET-53(30nm) / LiF(0.5nm) / Al(150nm) are roughly the same as those of Example D1-1, the only difference being the different resonant TADF dyes.

[0282] Examples D1-26

[0283] The device meanings of ITO / HI-2(10nm) / HT-27(40nm) / T-26:10wt%T-19:1wt%E-345(30nm) / ET-53(30nm) / LiF(0.5nm) / Al(150nm) are roughly the same as those of Examples D1-25, the only difference being the different main materials.

[0284] Examples D1-27

[0285] The device structure of this embodiment is shown below:

[0286] The device meanings of ITO / HI-2(10nm) / HT-27(40nm) / D-1:A-3:10wt%T-19:1wt%E-345(30nm) / ET-53(30nm) / LiF(0.5nm) / Al(150nm) are roughly the same as those of Examples D1-26, the only difference being the different main materials.

[0287] Examples D1-28

[0288] The device structure of this embodiment is shown below:

[0289] The device meanings of ITO / HI-2(10nm) / HT-27(40nm) / W-7:10wt%T-19:1wt%E-416(30nm) / ET-53(30nm) / LiF(0.5nm) / Al(150nm) are roughly the same as those of Example D1-1, the only difference being the different resonant TADF dyes.

[0290] Example D1-29

[0291] The device structure of this embodiment is shown below:

[0292] The device meanings of ITO / HI-2(10nm) / HT-27(40nm) / T-26:10wt%T-19:1wt%E-416(30nm) / ET-53(30nm) / LiF(0.5nm) / Al(150nm) are roughly the same as those of Examples D1-28, the only difference being the different main materials.

[0293] Examples D1-30

[0294] The device structure of this embodiment is shown below:

[0295] The device meanings of ITO / HI-2(10nm) / HT-27(40nm) / D-1:A-3:10wt%T-19:1wt%E-416(30nm) / ET-53(30nm) / LiF(0.5nm) / Al(150nm) are roughly the same as those of Examples D1-28, the only difference being the different main materials.

[0296] Examples D1-31

[0297] The device structure of this embodiment is shown below:

[0298] The device meanings of ITO / HI-2(10nm) / HT-27(40nm) / W-7:10wt%T-19:1wt%E-480(30nm) / ET-53(30nm) / LiF(0.5nm) / Al(150nm) are roughly the same as those of Example D1-1, the only difference being the different resonant TADF dyes.

[0299] Examples D1-32

[0300] The device structure of this embodiment is shown below:

[0301] The device meanings of ITO / HI-2(10nm) / HT-27(40nm) / T-26:10wt%T-19:1wt%E-480(30nm) / ET-53(30nm) / LiF(0.5nm) / Al(150nm) are roughly the same as those of Examples D1-31, the only difference being the different main materials.

[0302] Examples D1-33

[0303] The device structure of this embodiment is shown below:

[0304] The device meanings of ITO / HI-2(10nm) / HT-27(40nm) / D-1:A-3:10wt%T-19:1wt%E-480(30nm) / ET-53(30nm) / LiF(0.5nm) / Al(150nm) are roughly the same as those of Examples D1-31, the only difference being the different main materials.

[0305] Examples D1-34

[0306] The device structure of this embodiment is shown below:

[0307] The device meanings of ITO / HI-2(10nm) / HT-27(40nm) / W-7:10wt%T-19:1wt%E-508(30nm) / ET-53(30nm) / LiF(0.5nm) / Al(150nm) are roughly the same as those of Example D1-1, the only difference being the different resonant TADF dyes.

[0308] Examples D1-35

[0309] The device structure of this embodiment is shown below:

[0310] The device meanings of ITO / HI-2(10nm) / HT-27(40nm) / T-26:10wt%T-19:1wt%E-508(30nm) / ET-53(30nm) / LiF(0.5nm) / Al(150nm) are roughly the same as those of Examples D1-34, the only difference being the different main materials.

[0311] Examples D1-36

[0312] The device structure of this embodiment is shown below:

[0313] The device meanings of ITO / HI-2(10nm) / HT-27(40nm) / D-1:A-3:10wt%T-19:1wt%E-508(30nm) / ET-53(30nm) / LiF(0.5nm) / Al(150nm) are roughly the same as those of Examples D1-34, the only difference being the different main materials.

[0314] Example D1-37

[0315] The device structure of this embodiment is shown below:

[0316] The device meanings of ITO / HI-2(10nm) / HT-27(40nm) / W-7:10wt%T-19:1wt%E-518(30nm) / ET-53(30nm) / LiF(0.5nm) / Al(150nm) are roughly the same as those of Examples D1-34, the only difference being the different main materials.

[0317] Examples D1-38

[0318] The device structure of this embodiment is shown below:

[0319] The device meanings of ITO / HI-2(10nm) / HT-27(40nm) / T-26:10wt%T-19:1wt%E-518(30nm) / ET-53(30nm) / LiF(0.5nm) / Al(150nm) are roughly the same as those of Examples D1-37, the only difference being the different main materials.

[0320] Examples D1-39

[0321] The device structure of this embodiment is shown below:

[0322] The device significance of ITO / HI-2(10nm) / HT-27(40nm) / W-7:10wt%T-19:1wt%E-520(30nm) / ET-53(30nm) / LiF(0.5nm) / Al(150nm) is roughly the same as that of Example D1-1, the only difference being the different resonant thermally activated delayed fluorescent dyes.

[0323] Examples D1-40

[0324] The device structure of this embodiment is shown below:

[0325] The device significance of ITO / HI-2(10nm) / HT-27(40nm) / W-7:10wt%T-19:1wt%E-529(30nm) / ET-53(30nm) / LiF(0.5nm) / Al(150nm) is roughly the same as that of Example D1-1, the only difference being the different resonant thermally activated delayed fluorescent dyes.

[0326] Example D1-41

[0327] The device structure of this embodiment is shown below:

[0328] The device significance of ITO / HI-2(10nm) / HT-27(40nm) / W-7:10wt%T-19:1wt%E-545(30nm) / ET-53(30nm) / LiF(0.5nm) / Al(150nm) is roughly the same as that of Example D1-1, the only difference being the different resonant thermally activated delayed fluorescent dyes.

[0329] In the organic electroluminescent devices prepared below, the sensitizing material in the light-emitting layer is a phosphorus photosensitizer. Please refer to Table 1 for specific device performance details.

[0330] Device Example D2-1

[0331] The device structure of this embodiment is shown below:

[0332] ITO / HI-3(10nm) / HT-2(40nm) / W-7:10wt%PD-3:1wt%E-1(30nm) / ET-34(30nm) / LiF(0.5nm) / Al(150nm)

[0333] The anode is ITO; the hole injection layer is made of HI-3, with a total thickness of 5-30 nm, and 10 nm in this embodiment; the hole transport layer is made of HT-2, with a total thickness of 5-500 nm, and 40 nm in this embodiment; the main material of the organic light-emitting layer is wide bandgap material W-7, the phosphorus photosensitizer is PD-3 with a doping concentration of 10 wt%, the dye is boron-nitrogen heterocyclic narrow band fluorescent material, i.e., resonant TADF material E-1 with a doping concentration of 1 wt%, the thickness of the organic light-emitting layer is generally 1-200 nm, and 30 nm in this embodiment; the electron transport layer is made of ET-34, with a thickness of 5-300 nm, and 30 nm in this embodiment; the electron injection layer and cathode materials are LiF (0.5 nm) and aluminum (150 nm), with LiF vacuum-deposited at 0.5 nm / s as the electron injection layer and Al layer vacuum-deposited at 0.5-1 nm / s as the cathode of the device.

[0334] Device Example D2-2

[0335] The device structure of this embodiment is shown below:

[0336] The device meanings of ITO / HI-3(10nm) / HT-2(40nm) / H15:10wt% PD-3:1wt% E-1(30nm) / ET-34(30nm) / LiF(0.5nm) / Al(150nm) are roughly the same as those of Example D2-1, with the only difference being the main body.

[0337] Device Examples D2-3

[0338] The device structure of this embodiment is shown below:

[0339] The device in ITO / HI-3(10nm) / HT-2(40nm) / D13:A11:10wt%PD-3:1wt%E-1(30nm) / ET-34(30nm) / LiF(0.5nm) / Al(150nm) has a similar meaning to that in Example D2-1, except that the main body is replaced by an excitocomposite main body, i.e., an equimolar mixture of D13 and A11.

[0340] Device Examples D2-4

[0341] The device structure of this embodiment is shown below:

[0342] The device meanings of ITO / HI-3(10nm) / HT-2(40nm) / W-7:10wt% PD-3:1wt% E-58(30nm) / ET-34(30nm) / LiF(0.5nm) / Al(150nm) are roughly the same as those of Example D2-1, the only difference being the dye.

[0343] Device Examples D2-5

[0344] The device structure of this embodiment is shown below:

[0345] The device meanings of ITO / HI-3(10nm) / HT-2(40nm) / H15:10wt% PD-3:1wt% E-58(30nm) / ET-34(30nm) / LiF(0.5nm) / Al(150nm) are roughly the same as those of Example D2-2, the only difference being the dye.

[0346] Device Examples D2-6

[0347] The device structure of this embodiment is shown below:

[0348] The device meanings of ITO / HI-3(10nm) / HT-2(40nm) / D13:A11:10wt%PD-3:1wt%E-58(30nm) / ET-34(30nm) / LiF(0.5nm) / Al(150nm) are roughly the same as those of Examples D2-3, the only difference being the dye.

[0349] Device Examples D2-7

[0350] The device structure of this embodiment is shown below:

[0351] The device meanings of ITO / HI-3(10nm) / HT-2(40nm) / W-7:10wt% PD-3:1wt% E-62(30nm) / ET-34(30nm) / LiF(0.5nm) / Al(150nm) are roughly the same as those of Example D2-1, the only difference being the dye.

[0352] Device Examples D2-8

[0353] The device structure of this embodiment is shown below:

[0354] The device meanings of ITO / HI-3(10nm) / HT-2(40nm) / H15:10wt% PD-3:1wt% E-62(30nm) / ET-34(30nm) / LiF(0.5nm) / Al(150nm) are roughly the same as those of Example D2-2, the only difference being the dye.

[0355] Device Examples D2-9

[0356] The device structure of this embodiment is shown below:

[0357] The device meanings of ITO / HI-3(10nm) / HT-2(40nm) / D13:A11:10wt%PD-3:1wt%E-62(30nm) / ET-34(30nm) / LiF(0.5nm) / Al(150nm) are roughly the same as those of Examples D2-3, the only difference being the dye.

[0358] Device Example D2-10

[0359] The device structure of this embodiment is shown below:

[0360] The device meanings of ITO / HI-3(10nm) / HT-2(40nm) / W-7:10wt% PD-3:1wt% E-70(30nm) / ET-34(30nm) / LiF(0.5nm) / Al(150nm) are roughly the same as those of Example D2-1, the only difference being the dye.

[0361] Device Example D2-11

[0362] The device structure of this embodiment is shown below:

[0363] The device meanings of ITO / HI-3(10nm) / HT-2(40nm) / H15:10wt% PD-3:1wt% E-70(30nm) / ET-34(30nm) / LiF(0.5nm) / Al(150nm) are roughly the same as those of Example D2-2, the only difference being the dye.

[0364] Device Example D2-12

[0365] The device structure of this embodiment is shown below:

[0366] The device meanings of ITO / HI-3(10nm) / HT-2(40nm) / D13:A11:10wt%PD-3:1wt%E-70(30nm) / ET-34(30nm) / LiF(0.5nm) / Al(150nm) are roughly the same as those of Examples D2-3, the only difference being the dye.

[0367] Device Example D2-13

[0368] The device structure of this embodiment is shown below:

[0369] The device meanings of ITO / HI-3(10nm) / HT-2(40nm) / W-7:10wt%PD-3:1wt%E-201(30nm) / ET-34(30nm) / LiF(0.5nm) / Al(150nm) are roughly the same as those of Example D2-1, the only difference being the dye.

[0370] Device Example D2-14

[0371] The device structure of this embodiment is shown below:

[0372] The device meanings of ITO / HI-3(10nm) / HT-2(40nm) / H15:10wt% PD-3:1wt% E-201(30nm) / ET-34(30nm) / LiF(0.5nm) / Al(150nm) are roughly the same as those of Example D2-2, the only difference being the dye.

[0373] Device Example D2-15

[0374] The device structure of this embodiment is shown below:

[0375] The device meanings of ITO / HI-3(10nm) / HT-2(40nm) / D13:A11:10wt%PD-3:1wt%E-201(30nm) / ET-34(30nm) / LiF(0.5nm) / Al(150nm) are roughly the same as those of Examples D2-3, the only difference being the dye.

[0376] Device Example D2-16

[0377] The device structure of this embodiment is shown below:

[0378] The device meanings of ITO / HI-3(10nm) / HT-2(40nm) / W-7:10wt% PD-3:1wt% E-206(30nm) / ET-34(30nm) / LiF(0.5nm) / Al(150nm) are roughly the same as those of Example D2-1, the only difference being the dye.

[0379] Device Example D2-17

[0380] The device structure of this embodiment is shown below:

[0381] The device meanings of ITO / HI-3(10nm) / HT-2(40nm) / H15:10wt% PD-3:1wt% E-206(30nm) / ET-34(30nm) / LiF(0.5nm) / Al(150nm) are roughly the same as those of Example D2-2, the only difference being the dye.

[0382] Device Example D2-18

[0383] The device structure of this embodiment is shown below:

[0384] The device meanings of ITO / HI-3(10nm) / HT-2(40nm) / D13:A11:10wt%PD-3:1wt%E-206(30nm) / ET-34(30nm) / LiF(0.5nm) / Al(150nm) are roughly the same as those of Examples D2-3, the only difference being the dye.

[0385] Device Example D2-19

[0386] The device structure of this embodiment is shown below:

[0387] The device meanings of ITO / HI-3(10nm) / HT-2(40nm) / W-7:10wt% PD-3:1wt% E-345(30nm) / ET-34(30nm) / LiF(0.5nm) / Al(150nm) are roughly the same as those of Example D2-1, the only difference being the dye.

[0388] Device Example D2-20

[0389] The device structure of this embodiment is shown below:

[0390] The device meanings of ITO / HI-3(10nm) / HT-2(40nm) / H15:10wt% PD-3:1wt% E-345(30nm) / ET-34(30nm) / LiF(0.5nm) / Al(150nm) are roughly the same as those of Example D2-2, the only difference being the dye.

[0391] Device Example D2-21

[0392] The device structure of this embodiment is shown below:

[0393] The device meanings of ITO / HI-3(10nm) / HT-2(40nm) / D13:A11:10wt%PD-3:1wt%E-345(30nm) / ET-34(30nm) / LiF(0.5nm) / Al(150nm) are roughly the same as those of Examples D2-3, the only difference being the dye.

[0394] Device Example D2-22

[0395] The device structure of this embodiment is shown below:

[0396] The device meanings of ITO / HI-3(10nm) / HT-2(40nm) / W-7:10wt% PD-3:1wt% E-361(30nm) / ET-34(30nm) / LiF(0.5nm) / Al(150nm) are roughly the same as those of Example D2-1, the only difference being the dye.

[0397] Device Example D2-23

[0398] The device structure of this embodiment is shown below:

[0399] The device meanings of ITO / HI-3(10nm) / HT-2(40nm) / H15:10wt% PD-3:1wt% E-361(30nm) / ET-34(30nm) / LiF(0.5nm) / Al(150nm) are roughly the same as those of Example D2-2, the only difference being the dye.

[0400] Device Example D2-24

[0401] The device structure of this embodiment is shown below:

[0402] The device meanings of ITO / HI-3(10nm) / HT-2(40nm) / D13:A11:10wt%PD-3:1wt%E-361(30nm) / ET-34(30nm) / LiF(0.5nm) / Al(150nm) are roughly the same as those of Examples D2-3, the only difference being the dye.

[0403] Device Example D2-25

[0404] The device structure of this embodiment is shown below:

[0405] The device meanings of ITO / HI-3(10nm) / HT-2(40nm) / W-7:10wt% PD-3:1wt% E-508(30nm) / ET-34(30nm) / LiF(0.5nm) / Al(150nm) are roughly the same as those of Example D2-1, the only difference being the dye.

[0406] Device Example D2-26

[0407] The device structure of this embodiment is shown below:

[0408] The device meanings of ITO / HI-3(10nm) / HT-2(40nm) / H15:10wt% PD-3:1wt% E-508(30nm) / ET-34(30nm) / LiF(0.5nm) / Al(150nm) are roughly the same as those of Example D2-2, the only difference being the dye.

[0409] Device Example D2-27

[0410] The device structure of this embodiment is shown below:

[0411] The device meanings of ITO / HI-3(10nm) / HT-2(40nm) / D13:A11:10wt%PD-3:1wt%E-508(30nm) / ET-34(30nm) / LiF(0.5nm) / Al(150nm) are roughly the same as those of Examples D2-3, the only difference being the dye.

[0412] Device Example D2-28

[0413] The device structure of this embodiment is shown below:

[0414] The device meanings of ITO / HI-3(10nm) / HT-2(40nm) / W-7:10wt% PD-3:1wt% E-518(30nm) / ET-34(30nm) / LiF(0.5nm) / Al(150nm) are roughly the same as those of Example D2-1, the only difference being the dye.

[0415] Device Example D2-29

[0416] The device structure of this embodiment is shown below:

[0417] The device meanings of ITO / HI-3(10nm) / HT-2(40nm) / H15:10wt% PD-3:1wt% E-518(30nm) / ET-34(30nm) / LiF(0.5nm) / Al(150nm) are roughly the same as those of Example D2-2, the only difference being the dye.

[0418] Device Examples D2-30

[0419] The device structure of this embodiment is shown below:

[0420] The device meanings of ITO / HI-3(10nm) / HT-2(40nm) / D13:A11:10wt%PD-3:1wt%E-518(30nm) / ET-34(30nm) / LiF(0.5nm) / Al(150nm) are roughly the same as those of Examples D2-3, the only difference being the dye.

[0421] Device Example D2-31

[0422] The device structure of this embodiment is shown below:

[0423] The device meanings of ITO / HI-3(10nm) / HT-2(40nm) / W-7:10wt% PD-3:1wt% E-520(30nm) / ET-34(30nm) / LiF(0.5nm) / Al(150nm) are roughly the same as those of Example D2-1, the only difference being the dye.

[0424] Device Example D2-32

[0425] The device structure of this embodiment is shown below:

[0426] The device meanings of ITO / HI-3(10nm) / HT-2(40nm) / H15:10wt% PD-3:1wt% E-520(30nm) / ET-34(30nm) / LiF(0.5nm) / Al(150nm) are roughly the same as those of Example D2-2, the only difference being the dye.

[0427] Device Examples D2-33

[0428] The device structure of this embodiment is shown below:

[0429] The device meanings of ITO / HI-3(10nm) / HT-2(40nm) / D13:A11:10wt%PD-3:1wt%E-520(30nm) / ET-34(30nm) / LiF(0.5nm) / Al(150nm) are roughly the same as those of Examples D2-3, the only difference being the dye.

[0430] Device Examples D2-34

[0431] The device structure of this embodiment is shown below:

[0432] The device meanings of ITO / HI-3(10nm) / HT-2(40nm) / W-7:10wt% PD-3:1wt% E-529(30nm) / ET-34(30nm) / LiF(0.5nm) / Al(150nm) are roughly the same as those of Example D2-1, the only difference being the dye.

[0433] Device Example D2-35

[0434] The device structure of this embodiment is shown below:

[0435] The device meanings of ITO / HI-3(10nm) / HT-2(40nm) / H15:10wt% PD-3:1wt% E-529(30nm) / ET-34(30nm) / LiF(0.5nm) / Al(150nm) are roughly the same as those of Example D2-2, the only difference being the dye.

[0436] Device Example D2-36

[0437] The device structure of this embodiment is shown below:

[0438] The device representations of ITO / HI-3 (10nm) / HT-2 (40nm) / D13:A11:10wt% PD-3:1wt% E-529 (30nm) / ET-34 (30nm) / LiF (0.5nm) / Al (150nm) are largely the same as those in Examples D2-3, the only difference being the dye.

[0439] Device Example D2-37

[0440] The device structure of this embodiment is shown below:

[0441] The device meanings of ITO / HI-3(10nm) / HT-2(40nm) / W-7:10wt% PD-3:1wt% E-545(30nm) / ET-34(30nm) / LiF(0.5nm) / Al(150nm) are roughly the same as those of Example D2-1, the only difference being the dye.

[0442] Device Example D2-38

[0443] The device structure of this embodiment is shown below:

[0444] The device meanings of ITO / HI-3(10nm) / HT-2(40nm) / H15:10wt% PD-3:1wt% E-545(30nm) / ET-34(30nm) / LiF(0.5nm) / Al(150nm) are roughly the same as those of Example D2-2, the only difference being the dye.

[0445] Device Example D2-39

[0446] The device structure of this embodiment is shown below:

[0447] The device meanings of ITO / HI-3(10nm) / HT-2(40nm) / D13:A11:10wt%PD-3:1wt%E-545(30nm) / ET-34(30nm) / LiF(0.5nm) / Al(150nm) are roughly the same as those of Examples D2-3, the only difference being the dye.

[0448] The device prepared below is a comparative device of the present invention. For specific device performance, please refer to Table 1.

[0449] Comparative Example DB-1

[0450] The device structure of this comparative example is shown below:

[0451] The device meanings of ITO / HI-2(10nm) / HT-27(40nm) / T-26:1wt%E-1(30nm) / ET-53(30nm) / LiF(0.5nm) / Al(150nm) are roughly the same as those of Examples D1-3, the only difference being that no sensitizer is added.

[0452] Comparative Example DB-2

[0453] The device structure of this comparative example is shown below:

[0454] The device with the following structure is ITO / HI-2(10nm) / HT-27(40nm) / D-1,A-3:1wt%E-1(30nm) / ET-53(30nm) / LiF(0.5nm) / Al(150nm) and its device meaning is roughly the same as that in Examples D1-8, the only difference being that no sensitizer is added.

[0455] Comparative Example DB-3

[0456] The device structure of this embodiment is shown below:

[0457] The device meanings of ITO / HI-2(10nm) / HT-27(40nm) / T-26:1wt%E-508(30nm) / ET-53(30nm) / LiF(0.5nm) / Al(150nm) are roughly the same as those of Examples D1-35, the only difference being that no sensitizer is added.

[0458] Comparative Example DB-4

[0459] The device structure of this comparative example is shown below:

[0460] The device meanings of ITO / HI-2(10nm) / HT-27(40nm) / D-1,A-3:1wt%E-508(30nm) / ET-53(30nm) / LiF(0.5nm) / Al(150nm) are roughly the same as those of Examples D1-36, the only difference being that no sensitizer is added.

[0461] Comparative Example DB-5

[0462] The device structure of this comparative example is shown below:

[0463] The device ITO / HI-2(10nm) / HT-27(40nm) / W-7:10wt%T-19:1wt%TBPe(30nm) / ET-53(30nm) / LiF(0.5nm) / Al(150nm) has a similar device significance to experimental example D1-1, the only difference being that the light-emitting layer is replaced with a traditional fluorescent dye.

[0464] Comparative Example DB-6

[0465] The device structure of this comparative example is shown below:

[0466] The device with the following structure is roughly the same as that in experimental example D1-1: ITO / HI-2(10nm) / HT-27(40nm) / W-7:10wt%T-19:1wt%TPPA(30nm) / ET-53(30nm) / LiF(0.5nm) / Al(150nm). The only difference is that the light-emitting layer is replaced with a traditional fluorescent dye.

[0467] Comparative example DB-7

[0468] The device structure of this comparative example is shown below:

[0469] The device ITO / HI-2(10nm) / HT-27(40nm) / W-7:10wt%T-19:1wt%TBRb(30nm) / ET-53(30nm) / LiF(0.5nm) / Al(150nm) has a similar device significance to experimental example D1-1, the only difference being that the light-emitting layer is replaced with a traditional fluorescent dye.

[0470] Comparative Example DB-8

[0471] The device structure of this comparative example is shown below:

[0472] The device ITO / HI-2(10nm) / HT-27(40nm) / W-7:10wt%T-19:1wt%DBP(30nm) / ET-53(30nm) / LiF(0.5nm) / Al(150nm) has a similar device significance to experimental example D1-1, the only difference being that the emitting layer is replaced with a traditional fluorescent dye.

[0473] Comparative Example DB-9

[0474] The device structure of this embodiment is shown below:

[0475] The device with the following structure is roughly the same as that in Example D2-1: ITO / HI-3(10nm) / HT-2(40nm) / W-7:10wt% PD-3:1wt% E-529(30nm) / ET-34(30nm) / LiF(0.5nm) / Al(150nm), except that the dye is replaced with the traditional fluorescent dye TBRb.

[0476] Comparative Example DB-10

[0477] The device structure of this embodiment is shown below:

[0478] The device meaning of ITO / HI-3(10nm) / HT-2(40nm) / W-7:10wt%PD-3:1wt%DBP(30nm) / ET-34(30nm) / LiF(0.5nm) / Al(150nm) is roughly the same as that of Example D1-1, the only difference being that the dye is replaced with the traditional fluorescent dye DBP.

[0479] Table 1:

[0480]

[0481]

[0482]

[0483] In the organic electroluminescent device of this invention, a boron-nitrogen heterocyclic narrow-band fluorescent material is introduced as the luminescent dye. Due to the introduction of boron and nitrogen atoms into this type of compound, the HOMO and LUMO energy levels of the molecule can be effectively controlled. Simultaneously, due to the large conjugated system of the compound, the triplet energy level is significantly reduced, fully satisfying the condition that the triplet energy level is lower than that of the selected host and sensitizer. The reason for its ultra-narrow half-width emission is currently unknown, but it is speculated that the introduction of boron and nitrogen atoms, due to the difference in electronegativity, results in a certain localized state property in the orbital distribution within the conjugated system, enhancing molecular rigidity and suppressing shoulder peaks, thereby achieving ultra-high color purity emission.

[0484] As can be seen from the experimental results of the above-described device embodiments, the organic electroluminescent device of the present invention maintains high external quantum efficiency while exhibiting a small efficiency roll-off at high brightness, and its extremely narrow half-width at half-maximum (WHM) indicates good color purity. Furthermore, the device of this invention has a long lifespan, demonstrating overall superiority.

[0485] As can be seen from the experimental results of the comparative examples BD-1 to BD-9 above, the performance of the comparison devices without sensitizers is far inferior to that of the devices with sensitizers. This is because the TADF sensitizer can rapidly convert triplet states into singlet states through a reverse intersystem crossing process. These singlet states are then transferred to the dye singlet states via a FET, thus fully utilizing excitons. Similarly, the singlet states of the phosphorescent sensitizer and those generated by intersystem crossing can be transferred to the dye singlet states via a FET process, achieving 100% exciton utilization. Simultaneously, the rapid radiative transition rate of the dye ensures rapid radiation of the singlet states, preventing their conversion to triplet states, thereby achieving higher efficiency, lower roll-off, and longer lifetime.

[0486] This invention also provides a display device, which includes the organic electroluminescent device as described above. Specifically, the display device can be an OLED display or other display device, as well as any product or component with display function, such as a television, digital camera, mobile phone, or tablet computer, that includes the display device. The advantages of this display device over the prior art are the same as those of the organic electroluminescent device described above, and will not be repeated here.

[0487] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein, and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An organic electroluminescent device, comprising a substrate, a first electrode, a second electrode, and an organic functional layer, wherein the organic functional layer includes an organic light-emitting layer, and the organic light-emitting layer includes a host material and a luminescent dye, characterized in that, The luminescent layer includes a luminescent host material, a sensitizer, and a boron-nitrogen heterocyclic narrow-band fluorescent material used as a luminescent dye; The triplet energy level of the host material in the luminescent layer is higher than that of the sensitizer, and the triplet energy level of the host material is also higher than that of the boron-nitrogen heterocyclic narrow-band fluorescent material. The triplet energy level of the sensitizer is higher than the singlet and triplet energy levels of the boron-nitrogen heterocyclic narrowband fluorescent material, and the HOMO energy level of the sensitizer is deeper than the HOMO energy level of the boron-nitrogen heterocyclic narrowband fluorescent material. The sensitizer is selected from phosphorescent sensitizers or thermally activated delayed fluorescence sensitizers.

2. The organic electroluminescent device according to claim 1, wherein the boron-nitrogen heterocyclic narrow-band fluorescent material is selected from the structure shown in formula (1): in, R 1 ~R 10 Each group is independently selected from hydrogen, deuterium, halogen, hydroxyl, carboxyl, nitro, cyano, sulfone, sulfoxide, alkynyl, or unsubstituted or R'-substituted groups of the following: C1-C30 chain alkyl, C3-C30 cycloalkyl, C1-C10 alkoxy, C1-C10 thioalkyl, C6-C30 acyl, C6-C30 amino, C6-C30 arylamino, C3-C30 heteroarylamino, C6-C60 monocyclic aryl, C6-C60 fused-ring aryl, C6-C60 aryloxy, C6-C60 arylphosphinyl, C5-C60 monocyclic heteroaryl, C5-C60 fused-ring heteroaryl, C6-C30 alkylsilyl, C6-C30 arylsilyl, or C6-C30 heteroarylsilyl. The R' is independently selected from one of deuterium, halogen, cyano, C1-C30 chain alkyl, C3-C30 cycloalkyl, C1-C10 alkoxy, C6-C60 arylamino, C3-C60 heteroarylamino, C6-C60 aryl, and C3-C60 heteroaryl.

3. The organic electroluminescent device according to claim 2, wherein in formula (1), R 1 ~R 10 Each group is independently selected from hydrogen, deuterium, or one or more combinations of the following groups: methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, 2-methylbutyl, n-pentyl, sec-pentyl, cyclopentyl, neopentyl, n-hexyl, cyclohexyl, neohexyl, n-heptyl, cycloheptyl, n-octyl, cyclooctyl, 2-ethylhexyl, trifluoromethyl, pentafluoroethyl, 2,2,2-trifluoroethyl, ethynyl, trimethylsilylethynyl, tert-butylethynyl, triisopropylsilylethynyl, phenyl, tert-butylphenyl, naphthyl, anthracene, benzo[a]anthrayl, phenanthryl, benzo[a]phenanthryl, pyrene, peryl, uryl, fluoranyl, azulene, tetraphenyl, pentaphenyl, benzo[a]pyrene, biphenyl, azabiphenyl, azobiphenyl, terphenyl, Phenylacetyl, naphthylphenyl, phenyl terphenyl, tetraphenyl, fluorenyl, spirodifluorenyl, benzo[a]fluorenyl, dibenzo[a]fluorenyl, dihydrophenanthrene, dihydropyrene, tetrahydropyrene, cis or trans indo[a]fluorenyl, indene, trimerinyl, isotrimerininyl, spirotrimerininyl, spiroisotrimerininyl, triphenylene, furanyl, benzo[a]furanyl, isobenzo[a]furanyl, dibenzo[a]furanyl, thiazolyl Fenyl, benzothiophene, isobenzothiophene, dibenzothiophene, pyrrole, indole, isoindole, benzoindole, carbazole, benzocarbazole, indocarbazole, dibenzocarbazole, pyridyl, bipyridyl, quinolinyl, isoquinolinyl, cenolinyl, quinazolinyl, benzoquinazolinyl, benzodioxanepentenyl, acridine, dihydroacridyl, phenanthridine, benzene benzo-5,6-quinolinyl, benzo-6,7-quinolinyl, benzo-7,8-quinolinyl, pyrazolyl, indazoleyl, imidazoleyl, benzimidazoleyl, naphthomidazoleyl, phenanthrenemidazoleyl, pyridiniumimazoleyl, pyraziniumimazoleyl, quinoxaloylimazoleyl, oxazolyl, isoxazolyl, benzoxazolyl, benzoisoxazolyl, naphthomidazoleyl, anthraquinoxazolyl, phenanthrenemidazoleyl 1,2-Thiazolyl, 1,3-Thiazolyl, benzothiazolyl, benzoisothiazolyl, pyridinyl, benzopyridinyl, pyrimidinyl, benzopyrimidinyl, quinoxalinyl, benzoquinoxalinyl, 5,10-diazathanel, 2,7-diazapyrene, 2,3-diazapyrene, 1,6-diazapyrene, 1,8-diazapyrene, 4,5-diazapyrene, 4 5,9,10-Tetraazaperyl, Pyrazinyl, Phenazinyl, Phenoxazinyl, Phenthiazinyl, Naphridinyl, Azacarbazolyl, Benzocarbazolyl, Phenanthrolinel, 1,2,3-Triazolyl, 1,2,4-Triazolyl, Benzotriazolyl, 1,2,3-Oxadiazolyl, 1,2,4-Oxadiazolyl, 1,2,5-Oxadiazolyl, 1,2,3-Thiadiazolyl 1,2,4-Thiadiazolyl, 1,2,5-Thiadiazolyl, 1,3,4-Thiadiazolyl, 1,3,5-Triazinyl, 1,2,4-Triazinyl, 1,2,3-Triazinyl, Tetrazolyl, 1,2,4,5-Tetrazinyl, 1,2,3,4-Tetrazinyl, 1,2,3,5-Tetrazinyl, Purinyl, Pteridyl, Indazinyl, Benzothiadiazolyl, 9,9-Dimethylacridyl, triarylamine, adamantyl, fluorophenyl, methylphenyl, trimethylphenyl, cyanophenyl, tetrahydropyrrolyl, piperidinyl, methoxy, trisenel, cyclosenel, tetrastyrene, naphthimide, triphenylboryl, cycloheptanetrienyl, trimethylsilyl, triethylsilyl, triisopropylsilyl, triphenylsilyl, dimethylphenylsilyl, diphenylmethylsilyl, or tert-butyldiphenylsilyl.

4. The boron-nitrogen heterocyclic narrow-band fluorescent material according to claim 2 has the structure shown in formula (2): Wherein group R 9 and R 10 The scope of the definition is the same as that in equation (2); Preferably, the R 9 R 10 Each group is independently selected from one of the following groups: in Indicates the linking site of a functional group.

5. The organic electroluminescent device according to claim 1, wherein the boron-nitrogen heterocyclic narrow-band fluorescent material is selected from the following specific structural compounds:

6. The organic electroluminescent device according to claim 1, wherein the host material in the light-emitting layer is selected from wide bandgap materials, thermally activated delayed fluorescence materials, or excitocomplex materials; The wide bandgap material is selected from at least one compound selected from carbazole derivatives, carbline derivatives, spirofluorene derivatives, fluorene derivatives, silicon-based derivatives, phosphooxy derivatives, and sulfone-based derivatives. The thermally activated delayed fluorescence material is selected from at least one compound from benzonitrile derivatives, carbazole derivatives, spirofluorene derivatives, thiazole derivatives, and triazine derivatives; The excimer complex material comprises a donor material and an acceptor material. The donor material in the excimer complex material is selected from at least one compound selected from indolecarbazole derivatives, carbazole derivatives, furan derivatives, thiophene derivatives, spirofluorene derivatives, fluorene derivatives, silicon-containing derivatives, and diphenylamine derivatives. The acceptor material in the excimer complex material is selected from at least one compound selected from triazine derivatives, pyridone derivatives, imidazole derivatives, o-phenanthroline derivatives, thiophene derivatives, thionone derivatives, spirofluorene derivatives, fluorene derivatives, silicon-containing derivatives, cyano derivatives, phosphooxy derivatives, and sulfone derivatives.

7. The organic electroluminescent device according to claim 1 or 6, wherein the host material in the light-emitting layer is selected from at least one of the following structural compounds:

8. In the organic electroluminescent device according to claim 1 or 6, when the host material in the light-emitting layer is an excimer compound material, the donor material is selected from any one of the following structural compounds: The acceptor material in the excitocomplex is selected from any of the following structural compounds:

9. The organic electroluminescent device according to claim 1, wherein when the sensitizer is selected from phosphorus sensitizers, it is selected from one of the metal complex phosphorus sensitizers shown in the following structural formulas:

10. The organic electroluminescent device according to claim 1, wherein when the sensitizer is selected from thermally activated delayed fluorescence sensitizers, it is selected from benzonitrile derivatives or carbazole derivatives, and is selected from one of the compounds shown in the following structural formulas:

11. The organic electroluminescent device according to claim 1, wherein the doping concentration of the boron-nitrogen heterocyclic narrow-band fluorescent material in the luminescent layer is 0.1 wt% to 30 wt%, and the doping concentration of the sensitizer in the luminescent layer is 1 wt% to 50 wt%; Preferably, the doping concentration of the boron-nitrogen heterocyclic narrow-band fluorescent material in the luminescent layer is from 0.1 wt% to 10 wt%, and the doping concentration of the sensitizer in the luminescent layer is from 3 wt% to 30 wt%. More preferably, the doping concentration of the boron-nitrogen heterocyclic narrow-band fluorescent material in the luminescent layer is 0.1-2 wt%.

12. A display device, characterized in that, The display device includes the organic electroluminescent device of claim 1, wherein the display device is a display element, an illumination element, an information tag, an electronic artificial skin sheet, or electronic paper.

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