Light-emitting device and display device

Abstract

Disclosed is a light emitting device including a light emitting layer, the light emitting layer including a sensitizer; the emission spectrum of the sensitizer comprises a first emission peak and a second emission peak which are located on one side or two sides of the first emission peak, the maximum emission intensity of the second emission peak is smaller than that of the first emission peak, and the maximum emission intensity of the second emission peak is smaller than that of the second 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 0.10-0.55; an emission spectrum of the sensitizer comprises a first emission peak and a second emission peak, the second emission peak is located on one side or two sides of the first emission peak, and the maximum emission intensity of the second emission peak is limited to be smaller than the maximum emission intensity of the second emission peak. The increase of heat dissipation in the energy transfer process of the sensitizer due to the existence of the second emission peak can be reduced.

Description

Technical Field

[0001] The present application relates to the field of display technology, and in particular to a light-emitting device and a display apparatus. Background Art

[0002] Organic light emitting devices (OLEDs) are active light emitting devices with the advantages of light emission, ultra-thinness, wide viewing angle, high brightness, high contrast, low power consumption, and extremely high response speed. They have gradually become the next generation display technology with great development prospects. Generally, OLEDs include an anode, a cathode, and an organic light emitting layer arranged between the anode and the cathode. The principle of light emission is to inject holes and electrons from the anode and the cathode into the light emitting layer respectively. When electrons and holes meet in the light emitting layer, they recombine in the light emitting layer to generate excitons. These excitons emit light while changing from an excited state to a ground state.

[0003] At present, OLED devices are mainly sensitized devices, which refer to devices that use sensitizers in light-emitting devices, which can improve the luminous efficiency or stability of the device. Among them, the sensitizer can absorb energy and transfer it to the light-emitting molecules, thereby improving the luminous efficiency. However, the sensitizer will have a lot of heat dissipation during the energy transfer process, which reduces the luminous efficiency of the sensitizer. Summary of the invention

[0004] In view of this, the present application provides a light-emitting device and a display device, aiming to improve the problem of low light-emitting efficiency of existing sensitizer devices during use.

[0005] In a first aspect, an embodiment of the present application provides a light emitting device, including:

[0006] a light-emitting layer, the light-emitting layer comprising a sensitizer;

[0007] The emission spectrum of the sensitizer includes:

[0008] The first emission peak,

[0009] The second emission peak is located on one side or both sides of the first emission peak,

[0010] The maximum emission intensity of the second emission peak is less than the maximum emission intensity of the first emission peak;

[0011] 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.

[0012] Optionally, in some embodiments of the present application, the emission peak value of the first emission peak ranges from 400nm to 700nm.

[0013] Optionally, in some embodiments of the present application, the spectral half-peak width of the sensitizer is greater than or equal to 10 nm and less than or equal to 50 nm.

[0014] Optionally, in some embodiments of the present application, the half-peak width of the spectrum of the sensitizer ranges from 26 nm to 39 nm.

[0015] Optionally, in some embodiments of the present application, the half-peak width of the spectrum of the sensitizer ranges from 30 nm to 34 nm.

[0016] Optionally, in some embodiments of the present application, the normalized 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.

[0017] Optionally, in some embodiments of the present application, the normalized 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.

[0018] Optionally, in some embodiments of the present application, the normalized 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.

[0019] Optionally, in some embodiments of the present application, the normalized 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 0.20 to 0.50.

[0020] Optionally, in some embodiments of the present application, the normalized 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 0.20 to 0.21.

[0021] Optionally, in some embodiments of the present application, the normalized 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.

[0022] Optionally, in some embodiments of the present application, the sensitizer has a compound as shown in Formula I:

[0023]

[0024] Wherein, n1 is independently selected from 0, 1, 2, 3;

[0025] n2-n5 are independently selected from 0, 1, 2, 3, 4;

[0026] R1-R5 are independently selected from hydrogen atoms, deuterium atoms, halogen atoms, cyano groups, substituted or unsubstituted alkyl groups, substituted or unsubstituted alkenyl groups, substituted or unsubstituted alkynyl groups, substituted or unsubstituted cycloalkyl groups, substituted or unsubstituted heterocyclic groups, substituted or unsubstituted aryl groups, substituted or unsubstituted heteroaryl groups, substituted or unsubstituted borane groups, substituted or unsubstituted arylamine groups, substituted or unsubstituted aryloxy groups, and may form a ring with adjacent groups.

[0027] Optionally, in some embodiments of the present application, the sensitizer has a compound as shown in Formula II or a compound as shown in Formula III:

[0028]

[0029] in,

[0030] X is independently selected from O, S or NR 10 ;

[0031] L1 is independently selected from a single bond, O, S, NR 10 or -CR 16 R 17 -;

[0032] n6-n9 are independently selected from 0, 1, 2, 3, 4;

[0033] R6-R9 are independently selected from a hydrogen atom, a deuterium atom, a halogen atom, a cyano group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted alkynyl group, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted heterocycle, a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group, a substituted or unsubstituted borane group, a substituted or unsubstituted arylamine group, and a substituted or unsubstituted aryloxy group, and can form a ring with adjacent groups.

[0034] Optionally, in some embodiments of the present application, the sensitizer has any one of the compounds shown in Formula IV, Formula V, Formula VI or Formula VII;

[0035]

[0036] in,

[0037] X is independently selected from O, S or NR 10 ;

[0038] n6-n7, n 11 -n 15 Independently selected from 0, 1, 2, 3, 4;

[0039] R6-R7, R 11 -R 15The radicals are independently selected from hydrogen atoms, deuterium atoms, halogen atoms, cyano groups, substituted or unsubstituted alkyl groups, substituted or unsubstituted alkenyl groups, substituted or unsubstituted alkynyl groups, substituted or unsubstituted cycloalkyl groups, substituted or unsubstituted heterocyclic groups, substituted or unsubstituted aryl groups, substituted or unsubstituted heteroaryl groups, substituted or unsubstituted borane groups, substituted or unsubstituted arylamine groups, substituted or unsubstituted aryloxy groups, and may form a ring with adjacent groups.

[0040] Optionally, in some embodiments of the present application, the sensitizer includes any one of the following compounds:

[0041]

[0042]

[0043] Optionally, in some embodiments of the present application, the light-emitting layer further includes a host material, and the host material includes at least one of a P-type material and an N-type material.

[0044] Optionally, in some embodiments of the present application, the light-emitting layer further includes a fluorescent guest material, and a spectral half-peak width of the fluorescent guest material is greater than or equal to 10 nm and less than or equal to 50 nm.

[0045] In a second aspect, an embodiment of the present application provides a display device, comprising the aforementioned light-emitting device.

[0046] In a light-emitting device provided in an embodiment of the present application, the emission spectrum of the sensitizer includes a first emission peak and a second emission peak, and the second emission peak is located on one side or both sides of the first emission peak. The present application defines that the maximum emission intensity of the second emission peak is less than the maximum emission intensity of the second emission peak, which is beneficial to reducing the increase in heat dissipation during the energy transfer process of the sensitizer due to the presence of the second emission peak. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without paying any creative work.

[0048] Figure 1 is a schematic structural diagram of a light-emitting device provided in an embodiment of the present application;

[0049] Figure 2 is a flow chart of a method for preparing a light-emitting device provided in an embodiment of the present application;

[0050] Reference numerals:

[0051] 100. Light emitting device;

[0052] 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, covering layer. DETAILED DESCRIPTION

[0053] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without making creative work belong to the scope of protection of the present application. In addition, it should be understood that the specific implementation methods described herein are only used to illustrate and explain the present application, and are not used to limit the present application.

[0054] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0055] In this application, unless otherwise stated, directional words such as "upper" and "lower" generally refer to the upper and lower parts of the device in actual use or working state, specifically the drawing direction in the accompanying drawings; while "inner" and "outer" refer to the outline of the device. In addition, in the description of this application, the term "including" means "including but not limited to". The terms first, second, third, etc. are used only as labels and do not impose numerical requirements or establish an order.

[0056] In the present application, "at least one" means one or more, and "plurality" 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 items or plural items. For example, "at least one of a, b, or c", or "at least one of a, b, and c" can all mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be single or multiple, respectively.

[0057] In the present application, when a layer is formed "on" another layer, the so-called "on" is a broad concept, which may indicate that the formed another layer is adjacent to the certain layer, or may indicate that there are other spacing structural layers between the another layer and the certain layer. For example, when a second electrode is formed "on" the first carrier functional layer, the so-called "on" may indicate that the formed second electrode is adjacent to the first carrier functional layer, or may indicate that there are other spacing structural layers between the second electrode and the first carrier functional layer, such as a light-emitting layer.

[0058] Various embodiments of the present application may be presented in the form of a range; it should be understood that the description in the form of a range is only for convenience and brevity, and should not be understood as a rigid limitation on the scope of the present application; therefore, the range description should be considered to have specifically disclosed all possible sub-ranges and single numerical values ​​within the range. For example, the range description from 1 to 6 should be considered to have 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., as well as single numbers within the range, such as 1, 2, 3, 4, 5 and 6, which apply regardless of the range. In addition, whenever a numerical range is indicated herein, it is meant to include any cited number (fractional or integer) within the indicated range.

[0059] At present, OLED devices are mainly sensitized devices, which refer to devices that use sensitizers in light-emitting devices, which can improve the luminous efficiency or stability of the device. Among them, the sensitizer can absorb energy and transfer it to the fluorescent guest material, thereby improving the luminous efficiency.

[0060] Thermal dissipation refers to the process of heat transfer from a high temperature area to a low temperature area. In the process of the sensitizer absorbing energy and transferring energy to the fluorescent guest material, if the energy of the sensitizer is 100% transferred to the fluorescent guest material, the efficiency of the corresponding sensitized device can be improved by more than 30%. However, during the actual transfer process of the sensitizer, the efficiency of the phosphorescent sensitized device is improved by less than 20%, indicating that the sensitizer dissipates part of the energy in the form of heat through non-radiative pathways such as intramolecular conversion and vibration relaxation, which will increase thermal dissipation. Therefore, thermal dissipation should be reduced as much as possible to ensure that more energy is used in the photoelectric conversion process.

[0061] In view of this, an embodiment of the present application provides a light emitting device, including:

[0062] a light-emitting layer, the light-emitting layer comprising a sensitizer;

[0063] The emission spectrum of the sensitizer includes:

[0064] The first emission peak,

[0065] The second emission peak is located on one or both sides of the first emission peak.

[0066] The maximum emission intensity of the second emission peak is less than the maximum emission intensity of the first emission peak;

[0067] 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.

[0068] In a light-emitting device provided in an embodiment of the present application, the emission spectrum of the sensitizer includes a first emission peak and a second emission peak, and the second emission peak is located on one side or both sides of the first emission peak. The present application defines that the maximum emission intensity of the second emission peak is less than the maximum emission intensity of the second emission peak, which is beneficial to reducing the increase in heat dissipation during the energy transfer process of the sensitizer due to the presence of the second emission peak.

[0069] In some embodiments of the present application, the emission peak value of the first emission peak may range from 400 nm to 700 nm.

[0070] In some embodiments of the present 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. The ratio of the emission intensity of the second emission peak to the maximum emission intensity of the first emission peak will also affect the thermal dissipation of the sensitizer. If the ratio of the emission intensity of the second emission peak to the maximum emission intensity of the first emission peak is large, it indicates that the emission intensity of the second emission peak is large, which increases the possibility of non-radiative transition, causing the energy of the sensitizer to be dissipated in the form of heat. If the ratio of the emission intensity of the second emission peak to the maximum emission intensity of the first emission peak is small, the possibility of non-radiative transition is small, resulting in a reduction in the thermal dissipation of the sensitizer during the energy transfer process.

[0071] In some embodiments of the present application, the normalized 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 0.50.

[0072] In some embodiments of the present application, the normalized ratio of the emission intensity of the second emission peak to the maximum emission intensity of the first emission peak ranges from 0.30 to 0.50.

[0073] In some embodiments of the present application, the normalized 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.

[0074] In some embodiments of the present application, the normalized ratio of the emission intensity of the second emission peak to the maximum emission intensity of the first emission peak ranges from 0.20 to 0.21.

[0075] In some embodiments of the present application, the normalized 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.

[0076] In some embodiments of the present application, 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 may be 0.20 to 0.50.

[0077] In addition, the Full Width at Half Maximum (FWHM) of the spectrum of a sensitizer refers to the width at half the peak intensity in the spectrum.

[0078] In some embodiments of the present application, the half-peak width of the spectrum of the sensitizer may be greater than or equal to 10 nm and less than or equal to 50 nm. If the half-peak width of the spectrum of the sensitizer is large, the spectrum range of its absorption and emission is wide, which may cause energy to be dispersed in a non-target range, thereby increasing heat dissipation. Conversely, if the half-peak width of the spectrum of the sensitizer is small, the spectrum range of its absorption and emission is narrow, which is not easy to cause energy to be dispersed in a non-target range, thereby reducing heat dissipation.

[0079] In some embodiments of the present application, the half-peak width of the spectrum of the sensitizer may be greater than or equal to 26 nm and less than or equal to 39 nm.

[0080] In some embodiments of the present application, the half-peak width of the spectrum of the sensitizer may be greater than or equal to 30 nm and less than or equal to 34 nm.

[0081] In some embodiments of the present application, the light-emitting layer further includes a host material, and the host material includes at least one of a P-type material and an N-type material. The P-type material has a higher hole mobility, which is conducive to the injection and transmission of holes, and the N-type material has a higher electron mobility, which is conducive to the injection and transmission of electrons, thereby improving the luminous efficiency of the light-emitting device.

[0082] In some embodiments of the present application, the host material can be independently selected from the following chemical formulas:

[0083]

[0084] In some embodiments of the present application, the light-emitting layer further comprises a fluorescent guest material, and the spectral half-peak width of the fluorescent guest material is greater than or equal to 10 nm and less than or equal to 50 nm. If the spectral half-peak width is within the above range, it means that the half-peak width of the fluorescent guest material is narrow, which helps to concentrate the light emission in a smaller energy range, helps to reduce non-target light emission caused by spectral overlap, and thus reduces heat dissipation.

[0085] In some embodiments of the present application, the fluorescent guest material can be independently selected from the following chemical formulas:

[0086]

[0087]

[0088] In some embodiments of the present application, the doping concentration of the host material in the light-emitting 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.

[0089] In some embodiments of the present application, the doping concentration of the fluorescent guest material in the light-emitting layer can be 0.1%-1.5%. 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.

[0090] In some embodiments of the present application, the doping concentration of the sensitizer may 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.

[0091] In some embodiments of the present application, the doping concentration of the host material in the light-emitting layer may be 89%-97.8%, the doping concentration of the sensitizer may be 2%-10%, and the doping concentration of the fluorescent guest material may be 0.2%-1%.

[0092] It should be noted that the doping concentrations of the main material, sensitizer and fluorescent guest material directly affect the carrier transport, energy transfer efficiency and the generation and recombination process of excitons in the OLED device. For example, when the doping concentration of the main material is appropriate, the recombination efficiency of electrons and holes can be improved, and the accumulation of unrecombined carriers can be reduced, thereby reducing heat dissipation. For example, the doping concentration of the sensitizer affects the energy transfer efficiency between it and the fluorescent guest material. The appropriate sensitizer doping concentration can achieve efficient energy transfer and reduce energy loss in the form of heat. For example, the doping concentration of the fluorescent guest material affects the generation and recombination area of ​​the excitons. The appropriate doping concentration helps to form an effective exciton recombination area in the light-emitting layer, reduce the non-radiative recombination of excitons in the non-light-emitting area, and effectively reduce heat dissipation.

[0093] In addition, the molecular structure of the sensitizer will also affect heat dissipation, thereby affecting the luminous performance of the red, green, and blue (RGB) light-emitting unit.

[0094] In some embodiments of the present application, a platinum complex may be used as a ligand for a blue light-emitting unit, and at the same time, the sensitizer may have a molecular structure with high rigidity and stability.

[0095] As an example, the sensitizer may have a compound as shown in Formula I:

[0096]

[0097] Wherein, n1 is independently selected from 0, 1, 2, 3;

[0098] n2-n5 are independently selected from 0, 1, 2, 3, 4;

[0099] R1-R5 are independently selected from a hydrogen atom, a deuterium atom, a halogen atom, a cyano group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted alkynyl group, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted heterocycle, a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group, a substituted or unsubstituted borane group, a substituted or unsubstituted arylamine group, and a substituted or unsubstituted aryloxy group, and may form a ring with adjacent groups.

[0100] In some embodiments of the present application, the red light-emitting device and the green light-emitting device may use iridium complexes as ligands, but the ligands on one side of the sensitizer of the red light-emitting device and the green light-emitting device are different.

[0101] In some embodiments of the present application, for a green light-emitting device, the sensitizer may have a compound as shown in Formula II or a compound as shown in Formula III:

[0102]

[0103] in,

[0104] X is independently selected from O, S or NR 10 ;

[0105] L1 is independently selected from a single bond, O, S, NR 10 or -CR 16 R 17 -;

[0106] n6-n9 are independently selected from 0, 1, 2, 3, 4;

[0107] R6-R9 are independently selected from a hydrogen atom, a deuterium atom, a halogen atom, a cyano group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted alkynyl group, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted heterocycle, a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group, a substituted or unsubstituted borane group, a substituted or unsubstituted arylamine group, and a substituted or unsubstituted aryloxy group, and may form a ring with adjacent groups.

[0108] In some embodiments of the present application, the ratio of the emission intensity of the second emission peak in the sensitizer to the maximum emission intensity of the first emission peak is 0.32-0.41.

[0109] In some embodiments of the present application, the half-peak width of the spectrum of the sensitizer is 26-39 nm.

[0110] In some embodiments of the present application, for a red light-emitting device, the sensitizer may have any one of the compounds shown in Formula IV, Formula V, Formula VI or Formula VII;

[0111]

[0112] in,

[0113] X is independently selected from O, S or NR 10 ;

[0114] n6-n7, n 11 -n 15 Independently selected from 0, 1, 2, 3, 4;

[0115] R6-R7, R 11 -R 15 The radicals are independently selected from hydrogen atoms, deuterium atoms, halogen atoms, cyano groups, substituted or unsubstituted alkyl groups, substituted or unsubstituted alkenyl groups, substituted or unsubstituted alkynyl groups, substituted or unsubstituted cycloalkyl groups, substituted or unsubstituted heterocyclic groups, substituted or unsubstituted aryl groups, substituted or unsubstituted heteroaryl groups, substituted or unsubstituted borane groups, substituted or unsubstituted arylamine groups, and substituted or unsubstituted aryloxy groups, and may form a ring with adjacent groups.

[0116] In some embodiments of the present application, the ratio of the emission intensity of the second emission peak in the sensitizer to the maximum emission intensity of the first emission peak is 0.20-0.21.

[0117] In some embodiments of the present application, the half-peak width of the spectrum of the sensitizer is 30-34 nm.

[0118] In some embodiments of the present application, the sensitizer may include any one of the following compounds:

[0119]

[0120]

[0121] Reference Figure 1 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 covering layer 111 stacked in sequence.

[0122] In some embodiments of the present application, the substrate 101 may be a rigid substrate or a flexible substrate. In some embodiments, the material of the substrate 101 may include but is not limited to one or more of glass, silicon wafer, polycarbonate, polymethyl methacrylate, polyethylene terephthalate, polyethylene naphthalate, polyamide and polyether sulfone.

[0123] In some embodiments of the present application, the first electrode 102 and the second electrode 110 are electrodes known in the art for light-emitting devices. For example, they may independently include but are not limited to doped metal oxide electrodes, composite electrodes, graphene electrodes, carbon nanotube electrodes, metal single-substance electrodes or alloy electrodes. The material of the doped metal oxide electrode may include but is not limited to 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. One or more. The composite electrode is an electrode 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 " / " represents a stacked structure, for example, AZO / Ag / AZO represents a composite electrode including a sequentially stacked AZO layer, an Ag layer, and an AZO layer. The material of the metal single substance electrode may include, but is not limited to, one or more of Ag, Ni, Pt, Au, Ir, Cu, Mo, Al, Ca, Mg, and Ba. The alloy electrodes include, but are not limited to, Au:Mg alloy electrodes and Ag:Mg alloy electrodes.

[0124] In some embodiments of the present application, the first electrode 102 may be an anode, which is an electrode with a relatively high work function, such as but not limited to a doped metal oxide electrode with a relatively high work function, a metal single substance electrode with a relatively high work function, and a carbon nanotube electrode. The metal single substance electrode with a relatively high work function may be selected from but not limited to Ni, Pt, Au, Ag, Ir, etc.

[0125] In some embodiments of the present application, the thickness of the first electrode 102 is 60-150 nm.

[0126] In some embodiments of the present application, the second electrode 110 may be a cathode, and the cathode is an electrode with a relatively low work function, for example, it may include but is not limited to a metal single substance 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 single substance electrode with a relatively low work function may be Ca, Ba, Al, Mg, etc. The composite electrode with a relatively low work function may 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 may be Au:Mg and Ag:Mg, etc.

[0127] In some embodiments of the present application, the thickness of the second electrode 110 is 10-110 nm.

[0128] In some embodiments of the present application, the material of the hole injection layer 103 can be a material known in the art for a hole injection layer, for example, it can be selected from but not limited to one or more of 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene (HAT-CN), PEDOT, PEDOT:PSS, a derivative of PEDOT:PSS doped with s-MoO3 (PEDOT:PSS:s-MoO3), 4,4',4'-tris(N-3-methylphenyl-N-phenylamino)triphenylamine (m-MTDATA), tetracyanoquinodimethane (F4-TCQN), copper phthalocyanine, nickel oxide, molybdenum oxide, tungsten oxide, vanadium oxide, molybdenum sulfide, tungsten sulfide and copper oxide.

[0129] In some embodiments of the present application, the thickness of the hole injection layer 103 is 5-100 nm.

[0130] In some embodiments of the present application, the material of the hole transport layer 104 can be selected from, but 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)-(1,1'-biphenyl)-4,4'-diamine. )-N,N'-bis(phenyl)-spiro, N,N'-bis(4-(N,N'-diphenyl-amino)phenyl)-N,N'-diphenylbenzidine, 4,4',4'-tri(N-carbazolyl)-triphenylamine, 4,4',4'-tri(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'-di(1-naphthyl)-N,N'-diphenyl-1,1'-biphenyl-4-4'-diamine( NPB), spiro NPB, poly(phenylene vinylene), poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylene vinylene], poly[2-methoxy-5-(3',7'-dimethyloctyloxy)-1,4-phenylene vinylene], 2,2',7,7'-tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9'-spirobifluorene, 4,4'-cyclohexylbis[N,N-di(4-methylphenyl)aniline] (TAPC), 1,3-bis(carbazol-9-yl)benzene, polyaniline, polypyrrole, poly(p-)phenylene vinylene, aromatic tertiary amines, polynuclear One or more of aromatic tertiary amines, 4,4'-bis(p-carbazolyl)-1,1'-biphenyl compounds, N,N,N',N'-tetraarylbenzidine, PEDOT:PSS and its derivatives, polymethacrylate and its 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, and doped or undoped CuO.

[0131] In some embodiments of the present application, the thickness of the hole transport layer 104 is 20-150 nm.

[0132] In some embodiments of the present application, the electron blocking layer 105 is mainly used to block electrons and excitons generated in the light-emitting layer 106, and to transfer holes. The molecular formula of the material of the electron blocking layer 105 and the hole transport material in the light-emitting layer 106 can be the same or different.

[0133] In some embodiments of the present application, the thickness of the electron blocking layer 105 is 0-100 nm.

[0134] In some embodiments of the present application, the thickness of the light emitting layer 106 is 10-60 nm.

[0135] In some embodiments of the present application, the hole blocking layer 107 is mainly used to block holes and excitons generated in the light-emitting layer, and to transmit electrons. The material of the hole blocking layer 107 may include any one or more of 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, diazaphosphole derivative hole blocking layer materials, aromatic ketone derivative hole blocking layer materials, and borane derivative hole blocking layer materials.

[0136] In some embodiments of the present application, the thickness of the hole blocking layer 107 is 0-10 nm.

[0137] In some embodiments of the present 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.

[0138] In some embodiments of the present application, the electron transport layer 108 is mainly used to transport electrons. The material of the electron transport layer 108 includes an electron transport material and Liq doped together, and the doping mass ratio of the two is 10:1 to 1:1. The thickness of the electron transport layer 108 is between 10-50nm, and Liq can be selected from the material The electron transport material contains at least one or

[0139] In some embodiments of the present application, the thickness of the electron transport layer 108 is 10-60 nm.

[0140] In some embodiments of the present 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 not limited to one or more combinations of materials such as Yb, Li, LiF, NaCl, CsF, Li2O, BaO, and Liq.

[0141] In some embodiments of the present application, the thickness of the electron injection layer 109 is 0.1-10 nm.

[0142] In some embodiments of the present application, the cover layer 111 may be selectively disposed on the side of the second electrode 110 away from the light-emitting layer 106. The cover layer 111 is used to cover the second electrode 110, mainly to improve light extraction efficiency and protect the second electrode 110.

[0143] In some embodiments of the present application, the thickness of the cover layer 111 is 0-150 nm.

[0144] In some embodiments of the present application, the light emitting device 100 is a top emitting device.

[0145] 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 .

[0146] Reference Figure 2 The present invention provides a method for preparing a light-emitting device, comprising the following steps:

[0147] S100, providing a substrate;

[0148] S200, sequentially vapor depositing 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 covering layer on a surface of one side of the substrate.

[0149] In some embodiments of the present application, the electron blocking layer may be selectively evaporated between the hole transport layer and the light emitting layer.

[0150] In some embodiments of the present application, the hole blocking layer may be selectively evaporated between the light-emitting layer and the electron transporting layer.

[0151] An embodiment of the present application also provides a display device, comprising the aforementioned light-emitting device.

[0152] In some embodiments of the present application, the display device can be any electronic product with a display function, including but not limited to smart phones, tablet computers, laptops, digital cameras, digital video cameras, smart wearable devices, smart weighing electronic scales, car displays, televisions or e-book readers, among which the smart wearable device can be, for example, a smart bracelet, a smart watch, a virtual reality (VR) helmet, etc.

[0153] The present application is described in detail below by means of specific examples, which are only partial examples of the present application and are not intended to limit the present application. The raw materials used in the following examples are all commercially available products unless otherwise specified.

[0154] Example 1

[0155] A light-emitting device comprises 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 covering layer which are stacked in sequence;

[0156] The method for preparing the light emitting device of this embodiment comprises the following steps:

[0157] S100, providing a glass substrate;

[0158] S200, under vacuum conditions, evaporating ITO / Ag / ITO anode (15nm / 110nm / 15nm) on the surface of the glass substrate;

[0159] S300, HAT-CN was evaporated on the surface of ITO / Ag / ITO anode as a hole injection layer with a thickness of 10 nm;

[0160] S400, evaporating TAPC on the surface of the hole injection layer as a hole transport layer with a thickness of 120 nm;

[0161] S500, evaporating a light-emitting layer on the surface of the hole transport layer with a thickness of 40 nm;

[0162] The light-emitting layer includes a main material, a sensitizer and a fluorescent guest material, wherein the main material is a combination of 60% P-type material and 40% N-type material; the molecular structures of the main material, the sensitizer and the 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%;

[0163] S600, evaporating an electron transport material on the surface of the light-emitting layer and doping it with Liq at a ratio of 5:1 as an electron transport layer with a thickness of 30 nm;

[0164] S700, evaporating CsF on the surface of the electron transport layer as an electron injection layer with a thickness of 1 nm;

[0165] S800, evaporating cathode Mg / Ag alloy on the surface of the electron injection layer with a thickness of 1.2nm / 12nm;

[0166] S900: packaging to obtain a light-emitting device.

[0167] Table 1

[0168]

[0169] Example 2

[0170] A light-emitting device comprises 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 covering layer which are stacked in sequence;

[0171] The method for preparing the light emitting device of this embodiment comprises the following steps:

[0172] S100, providing a glass substrate;

[0173] S200, under vacuum conditions, evaporating ITO / Ag / ITO anode (15nm / 110nm / 15nm) on the surface of the glass substrate;

[0174] S300, HAT-CN was evaporated on the surface of ITO / Ag / ITO anode as a hole injection layer with a thickness of 10 nm;

[0175] S400, evaporating TAPC on the surface of the hole injection layer as a hole transport layer with a thickness of 120 nm;

[0176] S500, evaporating a light-emitting layer on the surface of the hole transport layer with a thickness of 40 nm;

[0177] The light-emitting layer includes a main material, a sensitizer and a fluorescent guest material, wherein the main material is a combination of 60% P-type material and 40% N-type material; the molecular structures of the main material, the sensitizer and the 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%;

[0178] S600, evaporating an electron transport material on the surface of the light-emitting layer and doping it with Liq at a ratio of 5:1 as an electron transport layer with a thickness of 30 nm;

[0179] S700, evaporating CsF on the surface of the electron transport layer as an electron injection layer with a thickness of 1 nm;

[0180] S800, evaporating cathode Mg / Ag alloy on the surface of the electron injection layer with a thickness of 1.2nm / 12nm;

[0181] S900: packaging to obtain a light-emitting device.

[0182] Table 2

[0183]

[0184] Example 3

[0185] A light-emitting device, which is different from Example 1 in that the sensitizer in the light-emitting layer is different. The molecular structure of the sensitizer in this example is shown in Table 3.

[0186] Table 3

[0187]

[0188] Example 4

[0189] A light-emitting device, which is different from Example 1 in that the sensitizer in the light-emitting layer is different. The molecular structure of the sensitizer in this example is shown in Table 4.

[0190] Table 4

[0191]

[0192] Example 5

[0193] A light-emitting device, which is different from Example 2 in that the sensitizer in the light-emitting layer is different. The molecular structure of the sensitizer in this example is shown in Table 5.

[0194] Table 5

[0195]

[0196] Example 6

[0197] A light-emitting device, which is different from Example 2 in that the sensitizer in the light-emitting layer is different. The molecular structure of the sensitizer in this example is shown in Table 6.

[0198] Table 6

[0199]

[0200]

[0201] Comparative Example 1

[0202] A light-emitting device, which is different from Example 1 in that the selection of the sensitizer in the light-emitting layer is different. The molecular structure of the sensitizer in this comparative example is shown in Table 7.

[0203] Table 7

[0204]

[0205] Comparative Example 2

[0206] A light-emitting device, which is different from Example 2 in that the selection of the sensitizer in the light-emitting layer is different. The molecular structure of the sensitizer in this comparative example is shown in Table 8.

[0207] Table 8

[0208]

[0209] Detection methods:

[0210] (1) The sensitizers in Examples 1-6 and Comparative Examples 1-2 were scanned using a spectrometer to obtain emission spectra of the sensitizers.

[0211] (2) Device efficiency: The light-emitting devices of the above-mentioned embodiment and the comparative example were subjected to a current density of 10 mA / cm 2 Under the conditions of , the luminous efficiency of the above device was tested.

[0212] The test results of the emission peak value, the spectral half-peak width, and the ratio of the emission intensity of the second emission peak to the maximum emission intensity of the first emission peak of the sensitizer in Examples 1-6 and Comparative Examples 1-2 are shown in Table 9.

[0213] Table 9

[0214]

[0215] Example 1, Examples 3-4 and Comparative Example 1 are all green light emitting devices. Referring to Table 9, it can be seen that the emission peak of the sensitizer is 522-528nm. The emission peak refers to the wavelength position when the emission intensity is the maximum in the emission spectrum of the sensitizer. Therefore, between 522-528nm, the luminescence efficiency of the sensitizer is the highest.

[0216] The half-peak width of the spectrum of the sensitizer in Example 1 and Examples 3-4 is 26-39nm. In addition, a second emission peak is generated on the descending side of the first emission peak, and 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. The half-peak width of the spectrum of the sensitizer in Comparative Example 1 is 57nm, 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, indicating that the ratio of the emission intensity of the second emission peak of the sensitizer in Comparative Example 1 to the maximum emission intensity of the first emission peak is large, which increases the possibility of non-radiative transition, resulting in the energy of the sensitizer being lost in the form of heat.

[0217] The efficiency of the light-emitting devices of Example 1 and Examples 3-4 is 120%-129%, while the efficiency of the light-emitting device of Comparative Example 1 is 115%, indicating that the use of the sensitizer of the present application to prepare the sensitized device is helpful to improve the efficiency of the device.

[0218] Example 2, Example 5-6 and Comparative Example 2 are all red light emitting devices. Referring to Table 9, it can be seen that the emission peak of the sensitizer is 615-627nm. The emission peak refers to the wavelength position when the emission intensity is the maximum in the emission spectrum of the sensitizer. Therefore, between 615-627nm, the luminous efficiency of the sensitizer is the highest. The spectrum half-peak width of the sensitizer in Example 2 and Example 5-6 is 30-34nm. In addition, a second emission peak will be generated on the descending side of the first emission peak, and 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; while the spectrum half-peak width of the sensitizer in Comparative Example 2 is 53nm, 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, indicating that the emission intensity of the second emission peak of the sensitizer in Comparative Example 2 is large, which increases the possibility of non-radiative transition, resulting in the energy of the sensitizer being lost in the form of heat.

[0219] The efficiency of the light-emitting devices of Examples 2 and 5-6 is 123%-124%, while the efficiency of the light-emitting device of Comparative Example 2 is 105%, indicating that the use of the sensitizer of the present application to prepare the sensitized device is helpful to improve the efficiency of the device.

[0220] The light-emitting device and display device provided in the embodiments of the present application are introduced in detail above. Specific examples are used in this article to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the method of the present application and its core idea. At the same time, for technical personnel in this field, according to the idea of ​​the present application, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as a limitation on the present application.

Claims

1. A light emitting device, characterized in that: include: a light-emitting layer, the light-emitting layer comprising a sensitizer; The emission spectrum of the sensitizer includes: The first emission peak, The second emission peak is located on one side 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, characterized in that: The emission peak value of the first emission peak ranges from 400nm to 700nm.

3. The light emitting device according to claim 1, characterized in that: The spectral half-peak width of the sensitizer is greater than or equal to 10 nm and less than or equal to 50 nm.

4. The light emitting device according to claim 1, characterized in that: The half-peak width of the spectrum of the sensitizer ranges from 26 nm to 39 nm.

5. The light emitting device according to claim 1, characterized in that: The spectrum half-peak width of the sensitizer ranges from 30 nm to 34 nm.

6. The light emitting device according to claim 1, characterized in that: 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, characterized in that: 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, characterized in that: 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, characterized in that: 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, characterized in that: 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, characterized in that: 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 according to claim 1, characterized in that: The sensitizer has a compound as shown in Formula I: Wherein, 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 atoms, deuterium atoms, halogen atoms, cyano groups, substituted or unsubstituted alkyl groups, substituted or unsubstituted alkenyl groups, substituted or unsubstituted alkynyl groups, substituted or unsubstituted cycloalkyl groups, substituted or unsubstituted heterocyclic groups, substituted or unsubstituted aryl groups, substituted or unsubstituted heteroaryl groups, substituted or unsubstituted borane groups, substituted or unsubstituted arylamine groups, substituted or unsubstituted aryloxy groups, and may form a ring with adjacent groups.

13. The light emitting device according to claim 1, characterized in that: 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 NR 10 ; L1 is independently selected from a single bond, O, S, NR 10 or -CR 16 R 17 -; n6-n9 are independently selected from 0, 1, 2, 3, 4; R6-R9 are independently selected from a hydrogen atom, a deuterium atom, a halogen atom, a cyano group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted alkynyl group, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted heterocycle, a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group, a substituted or unsubstituted borane group, a substituted or unsubstituted arylamine group, and a substituted or unsubstituted aryloxy group, and can form a ring with adjacent groups.

14. The light emitting device according to claim 1, characterized in that: The sensitizer is 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 NR 10 ; n6-n7, n 11 -n 15 Independently selected from 0, 1, 2, 3, 4; R6-R7, R 11 -R 15 The radicals are independently selected from hydrogen atoms, deuterium atoms, halogen atoms, cyano groups, substituted or unsubstituted alkyl groups, substituted or unsubstituted alkenyl groups, substituted or unsubstituted alkynyl groups, substituted or unsubstituted cycloalkyl groups, substituted or unsubstituted heterocyclic groups, substituted or unsubstituted aryl groups, substituted or unsubstituted heteroaryl groups, substituted or unsubstituted borane groups, substituted or unsubstituted arylamine groups, substituted or unsubstituted aryloxy groups, and may form a ring with adjacent groups.

15. The light emitting device according to claim 1, characterized in that: The sensitizer includes any one of the following compounds:

16. The light emitting device according to claim 1, characterized in that: The light-emitting layer further includes a host material, and the host material includes at least one of a P-type material and an N-type material.

17. The light emitting device according to claim 1, characterized in that: The light-emitting layer further comprises a fluorescent guest material, and the half-peak width of the spectrum 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, characterized in that: A light-emitting device comprising any one of claims 1-17.

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