Light-emitting device and display apparatus

Abstract

Disclosed in the present application is a light-emitting device, which comprises a light-emitting layer, wherein the light-emitting layer comprises a sensitizer, and the emission spectrum of the sensitizer comprises a first emission peak, and a second emission peak, which is located on one or both sides of the first emission peak, the maximum emission intensity at the second emission peak being smaller than the maximum emission intensity at the first emission peak, and the normalized value of the ratio of the emission intensity at the second emission peak to the maximum emission intensity at the first emission peak ranging from 0.10 to 0.55.

Description

Light-emitting devices and display devices

[0001] This application claims priority to Chinese patent application No. 202411436721.7, filed on October 14, 2024, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of display technology, and more particularly to a light-emitting device and a display apparatus. Background Technology

[0003] Organic light-emitting devices (OLEDs) are active-matrix light-emitting devices with advantages such as light emission, ultra-thinness, wide viewing angle, high brightness, high contrast, low power consumption, and extremely fast response speed. They have gradually become a promising next-generation display technology. A typical OLED consists of an anode, a cathode, and an organic light-emitting layer disposed between the anode and cathode. Its light-emitting principle involves injecting holes and electrons into the light-emitting layer from the anode and cathode, respectively. When electrons and holes meet in the light-emitting layer, they recombine to generate excitons. These excitons emit light as they transition from the excited state to the ground state.

[0004] Currently, OLED devices are mainly sensitized devices, which are devices that use sensitizers in the light-emitting device to improve the device's luminous efficiency or stability. Specifically, the sensitizer absorbs energy and transfers it to the light-emitting molecules, thereby improving luminous efficiency. Technical issues

[0005] This application provides a light-emitting device and a display device, which aims to improve the problem of reduced luminous efficiency of sensitizers in existing sensitizers due to excessive heat dissipation during energy transfer. Technical solutions

[0006] In a first aspect, embodiments of this application provide a light-emitting device, including:

[0007] A light-emitting layer, wherein the light-emitting layer includes a sensitizer;

[0008] The emission spectrum of the sensitizer includes:

[0009] First launch peak,

[0010] The second emission peak is located on one or both sides of the first emission peak.

[0011] The maximum emission intensity of the second emission peak is less than the maximum emission intensity of the first emission peak;

[0012] The normalized value range of the ratio of the emission intensity of the second emission peak to the maximum emission intensity of the first emission peak is 0.10 to 0.55.

[0013] Secondly, embodiments of this application provide a display device, including a light-emitting device;

[0014] The light-emitting device includes:

[0015] A light-emitting layer, wherein the light-emitting layer includes a sensitizer;

[0016] The emission spectrum of the sensitizer includes:

[0017] First launch peak,

[0018] The second emission peak is located on one or both sides of the first emission peak.

[0019] The maximum emission intensity of the second emission peak is less than the maximum emission intensity of the first emission peak;

[0020] The normalized value range of the ratio of the emission intensity of the second emission peak to the maximum emission intensity of the first emission peak is 0.10 to 0.55. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 is a schematic diagram of the structure of a light-emitting device provided in an embodiment of this application;

[0023] Figure 2 is a flowchart of a method for fabricating a light-emitting device according to an embodiment of this application;

[0024] Figure label:

[0025] 100. Light-emitting devices;

[0026] 101. Substrate; 102. First electrode; 103. Hole injection layer; 104. Hole transport layer; 105. Electron blocking layer; 106. Light emitting layer; 107. Hole blocking layer; 108. Electron transport layer; 109. Electron injection layer; 110. Second electrode; 111. Cover layer. Detailed Implementation

[0027] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application. Furthermore, it should be understood that the specific embodiments described herein are only for illustration and explanation of this application and are not intended to limit this application.

[0028] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the specification of this invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0029] In this application, unless otherwise stated, directional terms such as "upper" and "lower" generally refer to the upper and lower positions of the device in its actual use or operating state, specifically the drawing directions in the accompanying drawings; while "inner" and "outer" refer to the outline of the device. Furthermore, in the description of this application, the term "comprising" means "including but not limited to". The terms first, second, third, etc., are used merely as illustrative purposes and do not impose numerical requirements or establish a numerical order.

[0030] In this application, "at least one" means one or more, and "more than one" means two or more. "One or more", "at least one of the following", or similar expressions refer to any combination of these items, including any combination of single or multiple items. For example, "at least one of a, b, or c", or "at least one of a, b, and c" can both mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be single or multiple.

[0031] In this application, the term "on" forming another layer on a certain layer is a broad concept. It can mean that the formed other layer is adjacent to a certain layer, or it can mean that there are other spacer structures between the other layer and the certain layer. For example, when a second electrode is formed "on" a first charge carrier functional layer, the term "on" can mean that the formed second electrode is adjacent to the first charge carrier functional layer, or it can mean that there are other spacer structures between the second electrode and the first charge carrier functional layer, such as a light-emitting layer.

[0032] Various embodiments of this application may exist in the form of a range; it should be understood that the description in the form of a range is merely for convenience and brevity and should not be construed as a hard limitation on the scope of this application; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single numerical values ​​within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single numbers within the range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. Furthermore, whenever a numerical range is referred to herein, it means including any referenced number (fraction or integer) within the referred range.

[0033] Currently, sensitized devices are the main type of OLED devices. Sensitized devices are those that use sensitizers in the light-emitting device, which can improve the luminous efficiency or stability of the device. Specifically, sensitizers can absorb energy and transfer it to the fluorescent guest material, thereby improving luminous efficiency.

[0034] Heat dissipation refers to the process of heat transfer from a high-temperature region to a low-temperature region. In the process of a sensitizer absorbing energy and transferring it to a fluorescent guest material, if 100% of the sensitizer's energy is transferred to the fluorescent guest material, the efficiency of the corresponding sensitized device can be improved by more than 30%. However, in actual transfer processes, the efficiency improvement of phosphorescent sensitized devices is less than 20%, indicating that the sensitizer dissipates some energy as heat through non-radiative pathways such as intramolecular conversion and vibrational relaxation, thus increasing heat dissipation. Therefore, it is essential to minimize heat dissipation to ensure that more energy is used in the photoelectric conversion process.

[0035] In view of this, embodiments of this application provide a light-emitting device, including:

[0036] The light-emitting layer includes a sensitizer;

[0037] The emission spectrum of the sensitizer includes:

[0038] First launch peak,

[0039] The second launch peak is located to one or both sides of the first launch peak.

[0040] The maximum emission intensity of the second emission peak is less than the maximum emission intensity of the first emission peak.

[0041] The normalized value range of the ratio of the emission intensity of the second emission peak to the maximum emission intensity of the first emission peak is 0.10 to 0.55.

[0042] In a light-emitting device provided in this application embodiment, the emission spectrum of the sensitizer includes a first emission peak and a second emission peak. The second emission peak is located on one or both sides of the first emission peak. This application limits the maximum emission intensity of the second emission peak to be less than the maximum emission intensity of the second emission peak, which is beneficial to reduce the increase in heat dissipation during the energy transfer process of the sensitizer due to the presence of the second emission peak.

[0043] In some embodiments of this application, the emission peak value of the first emission peak can be in the range of 400nm to 700nm.

[0044] In some embodiments of this application, the ratio of the emission intensity of the second emission peak to the maximum emission intensity of the first emission peak can range from 0.10 to 0.55. This ratio also affects the heat dissipation of the sensitizer. If the ratio is large, it indicates a larger emission intensity of the second emission peak, increasing the likelihood of non-radiative transitions and causing the sensitizer's energy to dissipate as heat. Conversely, if the ratio is small, the likelihood of non-radiative transitions is lower, leading to reduced heat dissipation during energy transfer.

[0045] In some embodiments of this application, the normalized value of the ratio of the emission intensity of the second emission peak to the maximum emission intensity of the first emission peak is in the range of 0.10 to 0.50.

[0046] In some embodiments of this application, the normalized value of the ratio of the emission intensity of the second emission peak to the maximum emission intensity of the first emission peak is in the range of 0.30 to 0.50.

[0047] In some embodiments of this application, the normalized value of the ratio of the emission intensity of the second emission peak to the maximum emission intensity of the first emission peak ranges from 0.32 to 0.41.

[0048] In some embodiments of this application, the normalized value of the ratio of the emission intensity of the second emission peak to the maximum emission intensity of the first emission peak is between 0.20 and 0.21.

[0049] In some embodiments of this application, the normalized value of the ratio of the emission intensity of the second emission peak to the maximum emission intensity of the first emission peak ranges from 0.10 to 0.35.

[0050] In some embodiments of this application, the normalized value of the ratio of the emission intensity of the second emission peak to the maximum emission intensity of the first emission peak can be between 0.20 and 0.50.

[0051] In addition, the full width at half maximum (FWHM) of a sensitizer refers to the width at half the peak intensity in the spectrum.

[0052] In some embodiments of this application, the spectral half-width (HWHM) of the sensitizer can be greater than or equal to 10 nm and less than or equal to 50 nm. If the HWHM of the sensitizer is large, its absorption and emission spectral range is wide, which may lead to energy dispersion in the non-target range, thereby increasing heat dissipation. Conversely, if the HWHM of the sensitizer is small, its absorption and emission spectral range is narrow, which makes it less likely to cause energy dispersion in the non-target range, thereby reducing heat dissipation.

[0053] In some embodiments of this application, the full width at half maximum (FWHM) of the sensitizer may be greater than or equal to 26 nm and less than or equal to 39 nm.

[0054] In some embodiments of this application, the full width at half maximum (FWHM) of the sensitizer may be greater than or equal to 30 nm and less than or equal to 34 nm.

[0055] In some embodiments of this application, the light-emitting layer further includes a host material, which includes at least one of a P-type material and an N-type material. The P-type material has a higher hole mobility, which facilitates hole injection and transport, while the N-type material has a higher electron mobility, which facilitates electron injection and transport, thereby improving the luminous efficiency of the light-emitting device.

[0056] In some embodiments of this application, the host material may be independently selected from the following chemical formulas:

[0057] In some embodiments of this application, the luminescent layer further includes a fluorescent guest material, the half-width at half-maximum (WHM) of which is greater than or equal to 10 nm and less than or equal to 50 nm. A WHM within this range indicates that the fluorescent guest material has a narrow WHM, which helps to concentrate luminescence within a smaller energy range, reduces non-targeted luminescence caused by spectral overlap, and thus reduces heat dissipation.

[0058] In some embodiments of this application, the fluorescent guest material may be independently selected from the following chemical formulas:

[0059] In some embodiments of this application, the doping concentration of the host material in the luminescent layer can be 86.5%-97.9%, and the doping concentration of the host material is the ratio of the mass of the host material to the sum of the masses of the host material, the fluorescent guest material, and the sensitizer.

[0060] In some embodiments of this application, the doping concentration of the fluorescent guest material in the luminescent layer can be 0.1%-1.5%, and the doping concentration of the fluorescent guest material is the ratio of the mass of the fluorescent guest material to the sum of the masses of the host material, the fluorescent guest material, and the sensitizer.

[0061] In some embodiments of this application, the doping concentration of the sensitizer can be 1%-15%, and the doping concentration of the sensitizer is the ratio of the mass of the sensitizer to the sum of the masses of the host material, the fluorescent guest material, and the sensitizer.

[0062] In some embodiments of this application, the doping concentration of the host material in the luminescent layer can be 89%-97.8%, the doping concentration of the sensitizer can be 2%-10%, and the doping concentration of the fluorescent guest material can be 0.2%-1%.

[0063] It is important to note that the doping concentrations of the host material, sensitizer, and fluorescent guest material directly affect carrier transport, energy transfer efficiency, and exciton generation and recombination processes in OLED devices. For example, an appropriate doping concentration of the host material can improve the recombination efficiency of electrons and holes, reduce the accumulation of unrecombined carriers, and thus reduce heat dissipation. Similarly, the doping concentration of the sensitizer affects the energy transfer efficiency between it and the fluorescent guest material; a suitable sensitizer doping concentration can achieve efficient energy transfer and reduce energy loss as heat. Furthermore, the doping concentration of the fluorescent guest material affects the exciton generation and recombination region; an appropriate doping concentration helps form an effective exciton recombination region in the emitting layer, reducing non-radiative recombination of excitons in non-emitting regions and effectively reducing heat dissipation.

[0064] In addition, the molecular structure of the sensitizer also affects heat dissipation, which in turn affects the luminous performance of the red-green-blue (RGB) light-emitting unit.

[0065] In some embodiments of this application, platinum complexes can be used as ligands for blue luminescent units, while sensitizers can have molecular structures with high rigidity and stability.

[0066] As an example, a sensitizer can be a compound as shown in Formula I:

[0067] Where n1 is independently selected from 0, 1, 2, 3;

[0068] n2-n5 are independently selected from 0, 1, 2, 3, 4;

[0069] R1-R5 are independently selected from hydrogen, deuterium, halogen, cyano, substituted or unsubstituted alkyl, substituted or unsubstituted alkenyl, substituted or unsubstituted alkynyl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted heterocyclic, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, substituted or unsubstituted boronyl, substituted or unsubstituted aromatic amino, substituted or unsubstituted aryloxy, and may form a ring with adjacent groups.

[0070] In some embodiments of this application, the red and green light-emitting devices may use iridium complexes as ligands, but the ligands on one side of the sensitizer of the red and green light-emitting devices are different.

[0071] In some embodiments of this application, for green light-emitting devices, the sensitizer may be a compound as shown in Formula II or a compound as shown in Formula III:

[0072] in,

[0073] X is independently selected from O, S, or NR. 10 ;

[0074] L1 is independently selected from single bonds, O, S, NR. 10 or -CR 16 R 17 -;

[0075] n6-n9 are independently selected from 0, 1, 2, 3, 4;

[0076] R6-R9 are independently selected from hydrogen, deuterium, halogen, cyano, substituted or unsubstituted alkyl, substituted or unsubstituted alkenyl, substituted or unsubstituted alkynyl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted heterocyclic, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, substituted or unsubstituted boronyl, substituted or unsubstituted aromatic amino, substituted or unsubstituted aryloxy, and may form a ring with adjacent groups.

[0077] In some embodiments of this application, the ratio of the emission intensity of the second emission peak to the maximum emission intensity of the first emission peak in the sensitizer is 0.32-0.41.

[0078] In some embodiments of this application, the sensitizer has a spectral half-width of 26-39 nm.

[0079] In some embodiments of this application, for red light-emitting devices, the sensitizer may be any one of the compounds shown in Formula IV, Formula V, Formula VI or Formula VII;

[0080] in,

[0081] X is independently selected from O, S, or NR. 10 ;

[0082] n6-n7, n 11 -n 15 Independently selected from 0, 1, 2, 3, 4;

[0083] R6-R7, R 11 -R 15 It is independently selected from hydrogen atom, deuterium atom, halogen atom, cyano group, substituted or unsubstituted alkyl group, substituted or unsubstituted alkenyl group, substituted or unsubstituted alkynyl group, substituted or unsubstituted cycloalkyl group, substituted or unsubstituted heterocyclic group, substituted or unsubstituted aryl group, substituted or unsubstituted heteroaryl group, substituted or unsubstituted boroalkyl group, substituted or unsubstituted aromatic amino group, substituted or unsubstituted aryloxy group, and may form a ring with adjacent groups.

[0084] In some embodiments of this application, the ratio of the emission intensity of the second emission peak to the maximum emission intensity of the first emission peak in the sensitizer is 0.20-0.21.

[0085] In some embodiments of this application, the sensitizer has a spectral half-width of 30-34 nm.

[0086] In some embodiments of this application, the sensitizer may include any one of the following compounds:

[0087] Referring to FIG1, a light-emitting device 100 includes a substrate 101, a first electrode 102, a hole injection layer 103, a hole transport layer 104, an electron blocking layer 105, a light-emitting layer 106, a hole blocking layer 107, an electron transport layer 108, an electron injection layer 109, a second electrode 110, and a capping layer 111, which are stacked sequentially.

[0088] In some embodiments of this application, the substrate 101 may be a rigid substrate or a flexible substrate. In some embodiments, the material of the substrate 101 may be one or more of glass, silicon wafer, polycarbonate, polymethyl methacrylate, polyethylene terephthalate, polyethylene naphthalate, polyamide, and polyethersulfone.

[0089] In some embodiments of this application, the first electrode 102 and the second electrode 110 are electrodes known in the art for use in light-emitting devices. For example, they may be, independently, but not limited to, doped metal oxide electrodes, composite electrodes, graphene electrodes, carbon nanotube electrodes, elemental metal electrodes, or alloy electrodes. The materials for the doped metal oxide electrodes may include, but are not limited to, one or more of indium-doped tin oxide (ITO), fluorine-doped tin oxide (FTO), antimony-doped tin oxide (ATO), aluminum-doped zinc oxide (AZO), gallium-doped zinc oxide (GZO), indium-doped zinc oxide (IZO), magnesium-doped zinc oxide (MZO), aluminum-doped magnesium oxide (AMO), and cadmium-doped zinc oxide. Composite electrodes are electrodes formed by stacking two or more layers of conductive materials, such as AZO / Ag / AZO, AZO / Al / AZO, ITO / Ag / ITO, ITO / Al / ITO, ZnO / Ag / ZnO, ZnO / Al / ZnO, TiO2 / Ag / TiO2, TiO2 / Al / TiO2, ZnS / Ag / ZnS, ZnS / Al / ZnS, Ca / Al, LiF / Ca, LiF / Al, BaF2 / Al, CsF / Al, CaCO3 / Al, BaF2 / Ca / Al, etc., where " / " indicates a stacked structure. For example, AZO / Ag / AZO represents a composite electrode consisting of sequentially stacked AZO, Ag, and AZO layers. The materials for elemental metal electrodes can be, but are not limited to, one or more of Ag, Ni, Pt, Au, Ir, Cu, Mo, Al, Ca, Mg, and Ba. Alloy electrodes include, but are not limited to, Au:Mg alloy electrodes and Ag:Mg alloy electrodes.

[0090] In some embodiments of this application, the first electrode 102 can be an anode, which is an electrode with a relatively high work function. For example, it may include, but is not limited to, a doped metal oxide electrode with a relatively high work function, a metal element electrode with a relatively high work function, and a carbon nanotube electrode. The metal element electrode with the high work function can be selected from, but is not limited to, Ni, Pt, Au, Ag, Ir, etc.

[0091] In some embodiments of this application, the thickness of the first electrode 102 is 60-150 nm.

[0092] In some embodiments of this application, the second electrode 110 can be a cathode, which is an electrode with a relatively low work function. For example, it can include, but is not limited to, a metal element electrode with a relatively low work function, a composite electrode with a relatively low work function, and an alloy electrode with a relatively low work function. The metal element electrode with a relatively low work function can be Ca, Ba, Al, Mg, etc. The composite electrode with a relatively low work function can be Ca / Al, LiF / Ca, LiF / Al, BaF2 / Al, CsF / Al, CaCO3 / Al, BaF2 / Ca / Al, etc. The alloy electrode with a relatively low work function can be Au:Mg and Ag:Mg, etc.

[0093] In some embodiments of this application, the thickness of the second electrode 110 is 10 to 110 nm.

[0094] In some embodiments of this application, the material of the hole injection layer 103 may be a material known in the art for hole injection layers, such as, but not limited to, 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazabenzophenanthrene (HAT-CN), PEDOT, PEDOT:PSS, PEDOT:PSS derivatives doped with s-MoO3 (PEDOT:PSS:s-MoO3), 4,4',4'-tris(N-3-methylphenyl-N-phenylamino)triphenylamine (m-MTDATA), tetracyanoquinone dimethyl ether (F4-TCQN), copper phthalocyanine, nickel oxide, molybdenum oxide, tungsten oxide, vanadium oxide, molybdenum sulfide, tungsten sulfide, and copper oxide.

[0095] In some embodiments of this application, the thickness of the hole injection layer 103 is 5–100 nm.

[0096] In some embodiments of this application, the material of the hole transport layer 104 may be selected from, but is not limited to, 4,4'-N,N'-dicarbazolyl-biphenyl, poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine], N,N'-diphenyl-N,N'-bis(1-naphthyl)-1,1'-biphenyl-4,4”-diamine (α-NPD), N,N'-diphenyl-N,N'-bis(3-methylphenyl)-(1,1'-biphenyl)-4,4'-diamine, poly(N,N'-bis(4-butylphenyl)-N,N'-bis(phenyl)benzidine), N,N'-bis(3-methylphenyl) )-N,N'-bis(phenyl)-spiro, N,N'-bis(4-(N,N'-diphenyl-amino)phenyl)-N,N'-diphenylbenzidine, 4,4',4'-tris(N-carbazolyl)-triphenylamine, 4,4',4'-tris(N-3-methylphenyl-N-phenylamino)triphenylamine, poly[(9,9'-dioctylfluorene-2,7-diyl)-co-(4,4'-(N-(4-sec-butylphenyl)diphenylamine))], poly(N-vinylcarbazole) and its derivatives, N,N'-bis(1-naphthyl)-N,N'-diphenyl-1,1'-biphenyl-4-4'-diamine ( NPB), spiroNPB, poly(phenylenevinylene), poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene], poly[2-methoxy-5-(3',7'-dimethyloctyloxy)-1,4-phenylenevinylene], 2,2',7,7'-tetratetra[N,N-di(4-methoxyphenyl)amino]-9,9'-spirodifluorene, 4,4'-cyclohexylbis[N,N-di(4-methylphenyl)aniline](TAPC), 1,3-di(carbazole-9-yl)benzene, polyaniline, polypyrrole, poly(p)phenylenevinylene, aromatic tertiary amines, polynuclear Aromatic tertiary amines, 4,4'-bis(p-carbazolyl)-1,1'-biphenyl compounds, N,N,N',N'-tetraarylbenzidine, PEDOT:PSS and its derivatives, polymethacrylates and their derivatives, poly(9,9-octylfluorene) and its derivatives, poly(spirofluorene) and its derivatives, doped graphene, undoped graphene, C60, doped or undoped NiO, doped or undoped MoO3, doped or undoped WO3, doped or undoped V2O5, doped or undoped p-type gallium nitride, doped or undoped CrO3, doped or undoped CuO, or one or more of these.

[0097] In some embodiments of this application, the thickness of the hole transport layer 104 is 20–150 nm.

[0098] In some embodiments of this application, the electron blocking layer 105 is mainly used to block electrons and excitons generated within the light-emitting layer 106, as well as to transport holes. The material of the electron blocking layer 105 may have the same or different molecular formula as the hole transport material in the light-emitting layer 106.

[0099] In some embodiments of this application, the thickness of the electron blocking layer 105 is 0–100 nm.

[0100] In some embodiments of this application, the thickness of the light-emitting layer 106 is 10–60 nm.

[0101] In some embodiments of this application, the hole blocking layer 107 is mainly used to block holes and excitons generated within the light-emitting layer, as well as to transport electrons. The material of the hole blocking layer 107 may include any one or more of the following: benzimidazole derivative hole blocking layer materials, triazine derivative hole blocking layer materials, pyrimidine derivative hole blocking layer materials, pyridine derivative hole blocking layer materials, pyrazine derivative hole blocking layer materials, diazaphosphacyclopentadiene derivative hole blocking layer materials, aromatic ketone derivative hole blocking layer materials, and borane derivative hole blocking layer materials.

[0102] In some embodiments of this application, the thickness of the hole blocking layer 107 is 0–10 nm.

[0103] In some embodiments of this application, the material of the electron transport layer 108 includes, but is not limited to, one or more of quinoxaline compounds, imidazole compounds, triazine compounds, fluorene-containing compounds, and hydroxyquinoline compounds.

[0104] In some embodiments of this application, the electron transport layer 108 is primarily used for electron transport. The material of the electron transport layer 108 comprises an electron transport material and Liq doped together, with a doping mass ratio of 10:1 to 1:1. The thickness of the electron transport layer 108 is between 10-50 nm, and the Liq can be selected from materials... The electron transport material contains at least one group or

[0105] In some embodiments of this application, the thickness of the electron transport layer 108 is 10–60 nm.

[0106] In some embodiments of this application, the electron injection layer 109 is mainly used to reduce the electron injection barrier and improve the electron injection efficiency. The material of the electron injection layer 109 can be selected from, but is not limited to, one or more combinations of materials such as Yb, Li, LiF, NaCl, CsF, Li2O, BaO, and Liq.

[0107] In some embodiments of this application, the thickness of the electron injection layer 109 is 0.1–10 nm.

[0108] In some embodiments of this application, the cover layer 111 may be selectively disposed on the side of the second electrode 110 opposite to the light-emitting layer 106. The cover layer 111 is used to cover the second electrode 110, primarily to improve light extraction efficiency and protect the second electrode 110.

[0109] In some embodiments of this application, the thickness of the cover layer 111 is 0–150 nm.

[0110] In some embodiments of this application, the light-emitting device 100 is a top-emitting device.

[0111] It should be noted that the materials of each layer of the light-emitting device 100 can be adjusted according to the light-emitting requirements of the light-emitting device 100.

[0112] Referring to Figure 2, an embodiment of this application provides a method for fabricating a light-emitting device, comprising the following steps:

[0113] S100, provides a substrate;

[0114] S200, a first electrode, a hole injection layer, a hole transport layer, a light-emitting layer, an electron transport layer, an electron injection layer, a second electrode, and a capping layer are sequentially deposited on one side surface of the substrate.

[0115] In some embodiments of this application, the electron blocking layer may be selectively deposited between the hole transport layer and the light-emitting layer.

[0116] In some embodiments of this application, the hole blocking layer may be selectively deposited between the light-emitting layer and the electron transport layer.

[0117] This application also provides a display device, including the aforementioned light-emitting device.

[0118] In some embodiments of this application, the display device can be any electronic product with display function, including but not limited to smartphones, tablets, laptops, digital cameras, digital camcorders, smart wearable devices, smart weighing scales, in-vehicle displays, televisions, or e-book readers. Among them, smart wearable devices can be, for example, smart bracelets, smartwatches, virtual reality (VR) headsets, etc.

[0119] The present application will be specifically described below through specific embodiments. These embodiments are only some embodiments of the present application and are not intended to limit the present application. Unless otherwise specified, the raw materials used in the following embodiments are all commercially available products.

[0120] Example 1

[0121] A light-emitting device includes a substrate, a first electrode, a hole injection layer, a hole transport layer, a light-emitting layer, an electron transport layer, an electron injection layer, a second electrode, and a capping layer, which are stacked sequentially.

[0122] The method for fabricating the light-emitting device in this embodiment includes the following steps:

[0123] S100, provides glass substrate;

[0124] S200. Under vacuum conditions, ITO / Ag / ITO anodes (15nm / 110nm / 15nm) are deposited on the surface of a glass substrate by vapor deposition.

[0125] S300, HAT-CN is deposited on the surface of the ITO / Ag / ITO anode as a hole injection layer with a thickness of 10nm;

[0126] S400, TAPC is deposited on the surface of the hole injection layer as a hole transport layer with a thickness of 120nm;

[0127] S500: A light-emitting layer with a thickness of 40nm is deposited on the surface of the hole transport layer.

[0128] The luminescent layer comprises a host material, a sensitizer, and a fluorescent guest material. The host material is a combination of 60% P-type material and 40% N-type material. The molecular structures of the host material, sensitizer, and fluorescent guest material are shown in Table 1. The doping concentration of the sensitizer is 7%, and the doping concentration of the fluorescent guest material is 0.5%.

[0129] S600: Electron transport material and Liq are doped together in a 5:1 ratio on the surface of the light-emitting layer to form an electron transport layer with a thickness of 30 nm.

[0130] S700: CsF is deposited on the surface of the electron transport layer as an electron injection layer with a thickness of 1 nm.

[0131] S800, a cathode Mg / Ag alloy is vapor-deposited on the surface of the electron injection layer with a thickness of 1.2nm / 12nm;

[0132] S900, packaged, to obtain a light-emitting device.

[0133] Table 1

[0134] Example 2

[0135] A light-emitting device includes a substrate, a first electrode, a hole injection layer, a hole transport layer, a light-emitting layer, an electron transport layer, an electron injection layer, a second electrode, and a capping layer, which are stacked sequentially.

[0136] The method for fabricating the light-emitting device in this embodiment includes the following steps:

[0137] S100, provides glass substrate;

[0138] S200. Under vacuum conditions, ITO / Ag / ITO anodes (15nm / 110nm / 15nm) are deposited on the surface of a glass substrate by vapor deposition.

[0139] S300, HAT-CN is deposited on the surface of the ITO / Ag / ITO anode as a hole injection layer with a thickness of 10nm;

[0140] S400, TAPC is deposited on the surface of the hole injection layer as a hole transport layer with a thickness of 120nm;

[0141] S500: A light-emitting layer with a thickness of 40nm is deposited on the surface of the hole transport layer.

[0142] The luminescent layer comprises a host material, a sensitizer, and a fluorescent guest material. The host material is a combination of 60% P-type material and 40% N-type material. The molecular structures of the host material, sensitizer, and fluorescent guest material are shown in Table 2. The doping concentration of the sensitizer is 3%, and the doping concentration of the fluorescent guest material is 0.5%.

[0143] S600: Electron transport material and Liq are doped together in a 5:1 ratio on the surface of the light-emitting layer to form an electron transport layer with a thickness of 30 nm.

[0144] S700: CsF is deposited on the surface of the electron transport layer as an electron injection layer with a thickness of 1 nm.

[0145] S800, a cathode Mg / Ag alloy is vapor-deposited on the surface of the electron injection layer with a thickness of 1.2nm / 12nm;

[0146] S900, packaged, to obtain a light-emitting device.

[0147] Table 2

[0148] Example 3

[0149] A light-emitting device differs from Example 1 in that the sensitizer in the light-emitting layer is selected differently. The molecular structure of the sensitizer in this example is shown in Table 3.

[0150] Table 3

[0151] Example 4

[0152] A light-emitting device differs from Example 1 in that the sensitizer in the light-emitting layer is selected differently. The molecular structure of the sensitizer in this example is shown in Table 4.

[0153] Table 4

[0154] Example 5

[0155] A light-emitting device differs from that in Example 2 in that the sensitizer in the light-emitting layer is selected differently. The molecular structure of the sensitizer in this example is shown in Table 5.

[0156] Table 5

[0157] Example 6

[0158] A light-emitting device differs from that in Example 2 in that the sensitizer in the light-emitting layer is selected differently. The molecular structure of the sensitizer in this example is shown in Table 6.

[0159] Table 6

[0160] Comparative Example 1

[0161] A light-emitting device differs from Example 1 in that the sensitizer in the light-emitting layer is selected differently. The molecular structure of the sensitizer in this comparative example is shown in Table 7.

[0162] Table 7

[0163] Comparative Example 2

[0164] A light-emitting device differs from Example 2 in that the sensitizer in the light-emitting layer is selected differently. The molecular structure of the sensitizer in this comparative example is shown in Table 8.

[0165] Table 8

[0166] Detection methods:

[0167] (1) The emission spectra of the sensitizers in Examples 1-6 and Comparative Examples 1-2 were obtained by scanning with a spectrometer.

[0168] (2) Device efficiency: The light-emitting devices of the above embodiments and comparative examples were compared at a current density of 10 mA / cm². 2 Under the given conditions, the luminous efficiency of the above-mentioned devices was tested.

[0169] The detection results of emission peak value, spectral half-width, and the ratio of emission intensity of the second emission peak to the maximum emission intensity of the first emission peak for the sensitizers in Examples 1-6 and Comparative Examples 1-2 are shown in Table 9.

[0170] Table 9

[0171] Examples 1, 3-4 and Comparative Example 1 are all green light-emitting devices. As shown in Table 9, the emission peak of the sensitizer is 522-528 nm. The emission peak refers to the wavelength position where the emission intensity is the highest in the emission spectrum of the sensitizer. Therefore, the luminous efficiency of the sensitizer is the highest between 522-528 nm.

[0172] The sensitizers in Examples 1 and 3-4 have a spectral half-width of 26-39 nm. Furthermore, a second emission peak is generated on the descending side of the first emission peak. The emission intensity of the second emission peak is less than the maximum emission intensity of the first emission peak, and the ratio of the emission intensity of the second emission peak to the maximum emission intensity of the first emission peak is 0.32-0.41. In contrast, the sensitizer in Comparative Example 1 has a spectral half-width of 57 nm, and the ratio of the emission intensity of the second emission peak to the maximum emission intensity of the first emission peak is 0.60. This indicates that the ratio of the emission intensity of the second emission peak to the maximum emission intensity of the first emission peak in Comparative Example 1 is larger, increasing the possibility of non-radiative transitions and causing the sensitizer's energy to dissipate as heat.

[0173] The light-emitting devices of Examples 1 and 3-4 have an efficiency of 120%-129%, while the light-emitting device of Comparative Example 1 has an efficiency of 115%, indicating that using the sensitizer of this application to prepare sensitized devices helps to improve device efficiency.

[0174] Examples 2, 5-6, and Comparative Example 2 are all red light-emitting devices. Referring to Table 9, the emission peak of the sensitizer is 615-627 nm. The emission peak refers to the wavelength position where the emission intensity is highest in the emission spectrum of the sensitizer. Therefore, the luminous efficiency of the sensitizer is highest between 615-627 nm. The full width at half maximum (FWHM) of the sensitizer in Examples 2 and 5-6 is 30-34 nm. Furthermore, a second emission peak is generated on the descending side of the first emission peak. The emission intensity of the second emission peak is less than the maximum emission intensity of the first emission peak, and the ratio of the emission intensity of the second emission peak to the maximum emission intensity of the first emission peak is 0.20-0.21. In contrast, the FWHM of the sensitizer in Comparative Example 2 is 53 nm, and the ratio of the emission intensity of the second emission peak to the maximum emission intensity of the first emission peak is 0.59. This indicates that the ratio of the emission intensity of the second emission peak to the maximum emission intensity of the first emission peak in Comparative Example 2 is larger, increasing the possibility of non-radiative transitions and causing the sensitizer's energy to dissipate as heat.

[0175] The light-emitting devices of Examples 2 and 5-6 have an efficiency of 123%-124%, while the light-emitting device of Comparative Example 2 has an efficiency of 105%, indicating that using the sensitizer of this application to prepare sensitized devices helps to improve device efficiency.

[0176] The light-emitting device and display apparatus provided in the embodiments of this application have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A light-emitting device, comprising: A light-emitting layer, wherein the light-emitting layer includes a sensitizer; The emission spectrum of the sensitizer includes: First launch peak, The second emission peak is located on one or both sides of the first emission peak. The maximum emission intensity of the second emission peak is less than the maximum emission intensity of the first emission peak; The normalized value range of the ratio of the emission intensity of the second emission peak to the maximum emission intensity of the first emission peak is 0.10 to 0.

55.

2. The light-emitting device according to claim 1, wherein, The emission peak value of the first emission peak ranges from 400nm to 700nm.

3. The light-emitting device according to claim 1, wherein, The sensitizer has a full width at half maximum (FWHM) of 10 nm or greater and 50 nm or less.

4. The light-emitting device according to claim 1, wherein, The sensitizer has a spectral half-width ranging from 26 nm to 39 nm.

5. The light-emitting device according to claim 1, wherein, The sensitizer has a spectral half-width ranging from 30 nm to 34 nm.

6. The light-emitting device according to claim 1, wherein, The normalized value range of the ratio of the emission intensity of the second emission peak to the maximum emission intensity of the first emission peak is 0.10 to 0.

50.

7. The light-emitting device according to claim 1, wherein, The normalized value range of the ratio of the emission intensity of the second emission peak to the maximum emission intensity of the first emission peak is 0.30 to 0.

50.

8. The light-emitting device according to claim 1, wherein, The normalized value range of the ratio of the emission intensity of the second emission peak to the maximum emission intensity of the first emission peak is 0.32 to 0.

41.

9. The light-emitting device according to claim 1, wherein, The normalized value range of the ratio of the emission intensity of the second emission peak to the maximum emission intensity of the first emission peak is 0.20 to 0.

50.

10. The light-emitting device according to claim 1, wherein, The normalized value range of the ratio of the emission intensity of the second emission peak to the maximum emission intensity of the first emission peak is 0.20 to 0.

21.

11. The light-emitting device according to claim 1, wherein, The normalized value range of the ratio of the emission intensity of the second emission peak to the maximum emission intensity of the first emission peak is 0.10 to 0.

35.

12. The light-emitting device as claimed in claim 1, wherein, The sensitizer has a compound as shown in Formula I: Where n1 is independently selected from 0, 1, 2, 3; n2-n5 are independently selected from 0, 1, 2, 3, 4; R1-R5 are independently selected from hydrogen atom, deuterium atom, halogen atom, cyano group, substituted or unsubstituted alkyl group, substituted or unsubstituted alkenyl group, substituted or unsubstituted alkynyl group, substituted or unsubstituted cycloalkyl group, substituted or unsubstituted heterocyclic group, substituted or unsubstituted aryl group, substituted or unsubstituted heteroaryl group, substituted or unsubstituted boroalkyl group, substituted or unsubstituted aromatic amino group, substituted or unsubstituted aryloxy group, and may be cyclic with adjacent groups.

13. The light-emitting device as claimed in claim 1, wherein, The sensitizer has a compound as shown in Formula II or a compound as shown in Formula III: in, X is independently selected from O, S or N-R 10 ; L1is independently selected from a single bond, O, S, N-R 10 or -CR 16 R 17 -; n6-n9 are independently selected from 0, 1, 2, 3, 4; R6-R9 are independently selected from hydrogen, deuterium, halogen, cyano, substituted or unsubstituted alkyl, substituted or unsubstituted alkenyl, substituted or unsubstituted alkynyl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted heterocyclic, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, substituted or unsubstituted boronyl, substituted or unsubstituted aromatic amino, substituted or unsubstituted aryloxy, and may form a ring with adjacent groups.

14. The light-emitting device as claimed in claim 1, wherein, The sensitizer has any one of the compounds shown in Formula IV, Formula V, Formula VI or Formula VII; in, X is independently selected from O, S or N-R 10 ; n6-n7, n 11 -n 15 is independently selected from 0, 1, 2, 3, 4; R6-R7, R 11 -R 15 It is independently selected from hydrogen atom, deuterium atom, halogen atom, cyano group, substituted or unsubstituted alkyl group, substituted or unsubstituted alkenyl group, substituted or unsubstituted alkynyl group, substituted or unsubstituted cycloalkyl group, substituted or unsubstituted heterocyclic group, substituted or unsubstituted aryl group, substituted or unsubstituted heteroaryl group, substituted or unsubstituted boroalkyl group, substituted or unsubstituted aromatic amino group, substituted or unsubstituted aryloxy group, and may be cyclic with adjacent groups.

15. The light-emitting device as claimed in claim 1, wherein, The sensitizer includes any one of the following compounds:

16. The light-emitting device as claimed in claim 1, wherein, The light-emitting layer also includes a host material, which includes at least one of a P-type material and an N-type material.

17. The light-emitting device as claimed in claim 1, wherein, The luminescent layer further includes a fluorescent guest material, wherein the full width at half maximum (FWHM) of the fluorescent guest material is greater than or equal to 10 nm and less than or equal to 50 nm.

18. A display device comprising the light-emitting device according to any one of claims 1-17.

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