Light-emitting device and display apparatus

Abstract

This application discloses a light-emitting device and a display apparatus. The light-emitting device includes a stacked anode, a light-emitting layer, an electronic functional layer, and a cathode. The cathode is made of a metallic material and a thiadiazole compound. The light-emitting device proposed in this application introduces a thiadiazole compound into the cathode, which helps reduce the reactivity of the metal electrode, thereby reducing the probability of reaction between the metal electrode and the metal oxide in the electronic functional layer. This helps improve the luminous efficiency of the light-emitting device and extend its lifespan.

Description

Technical Field

[0001] This application relates to the field of semiconductor technology, and in particular to a light-emitting device and a display device. Background Technology

[0002] N-type inorganic semiconductors, such as zinc oxide and tin oxide, have high electron mobility and are widely used in the electron transport layer of light-emitting devices. However, in practical applications, it has been found that during high-temperature and high-voltage energization testing of light-emitting devices, N-type inorganic semiconductors tend to react with metal electrodes, partially converting into elemental metals, which in turn affects the light-emitting performance of the device. Summary of the Invention

[0003] In view of this, this application provides a light-emitting device and a display apparatus.

[0004] The embodiments of this application are implemented as follows:

[0005] In a first aspect, embodiments of this application provide a light-emitting device, including a stacked anode, a light-emitting layer, an electronic functional layer, and a cathode, wherein the cathode is made of a metallic material and a thiadiazole compound, wherein the thiadiazole compound has the structure shown in formula (Ⅰ);

[0006] Equation (Ⅰ):

[0007] Where n is 1 or 2;

[0008] Each time R appears, it is independently selected from one or more combinations of deuterium, nitro, amino, halogen, hydroxyl, carboxyl, sulfonic acid, aldehyde, mercapto, cyano, C1-C30 alkyl, C3-C30 cycloalkyl, C1-C30 alkoxy, C1-C30 alkylthio, C6-C30 aryl, C5-C30 heteroaryl, C6-C30 aryloxy, and C5-C30 heteroaryloxy.

[0009] Secondly, embodiments of this application provide a display device including the light-emitting device described above.

[0010] The light-emitting device proposed in this application introduces thiadiazole compounds into the cathode, which helps to reduce the reactivity of the electrode, thereby reducing the probability of the metal electrode reacting with the metal oxide in the electronic functional layer, which helps to improve the luminous efficiency of the light-emitting device and extend the device's lifespan. Attached Figure Description

[0011] 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.

[0012] Figure 1 This is a schematic diagram of the structure of a light-emitting device provided in the first embodiment of this application;

[0013] Figure 2 This is a schematic diagram of the structure of a light-emitting device provided in the second embodiment of this application;

[0014] Figure 3 This is a schematic diagram of the structure of a light-emitting device provided in the third embodiment of this application;

[0015] Figure 4 This is a schematic diagram of the structure of a light-emitting device provided in the fourth embodiment of this application;

[0016] Reference numerals: Light-emitting device 100; Anode 10; Doped electrode 21; Composite cathode 22; Electrode layer 221; Interface layer 222; Light-emitting layer 30; Hole transport layer 40; Hole injection layer 50; Electronic functional layer 60; Inorganic layer 61; Organic layer 62; Electron injection layer 63. Detailed Implementation

[0017] The technical solutions in 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 in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application. In addition, 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. In this application, unless otherwise stated, directional terms such as "upper" and "lower" specifically refer to the drawing directions in the accompanying drawings. In addition, in the description of this application, the term "including" means "including but not limited to". 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 only for convenience and conciseness 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 values ​​within that range. For example, it should be assumed that the description of a range from 1 to 6 specifically discloses subranges 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, regardless of the range. Furthermore, whenever a numerical range is referred to herein, it means including any referenced number (fraction or integer) within the range referred to.

[0018] In this application, "and / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. A and B can be singular or plural.

[0019] In this application, "at least one" means one or more, and "more than one" means two or more. "At least one," "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.

[0020] Terminology Explanation

[0021] In this application, "aryl" refers to an aromatic hydrocarbon group derived from an aromatic ring by removing one hydrogen atom. It can be a monocyclic aryl or a polycyclic aryl. For polycyclic rings, at least one is an aromatic ring system. Polycyclic aryl can be a fused aryl, or a group structure formed by multiple monocyclic or fused aryl groups linked by a single bond. A fused aryl refers to a group composed of two or more rings, where adjacent rings share two ring atoms. For example, a "naphthalene" ring is formed by the fusion of two benzene rings. For example, a C6-C30 aryl refers to an aryl containing 6 to 30 carbon atoms, preferably 6 to 14 carbon atoms, particularly preferably 6 to 10 carbon atoms, and optionally further substituted. Suitable examples include, but are not limited to: phenyl, biphenyl, terphenyl, naphthyl, anthracene, phenanthrene, fluoranyl, triphenylene, pyrene, perylene, tetraphenyl, fluorenyl, dinaphthylphenyl, acenaphthyl, and their derivatives. It is understandable that multiple aryl groups can also be interrupted by short non-aromatic units (e.g., <10% non-H atoms, such as C, N or O atoms), specifically acenaphthene, fluorene, or 9,9-diarylfluorene, triarylamine, and diaryl ether systems should also be included in the definition of aryl.

[0022] In this application, "heteroaryl" refers to an aryl group in which at least one carbon atom on the ring is replaced by a non-carbon atom (heteroatom), which can be an N atom, O atom, S atom, etc. For example, a C5-C18 heterocyclic group refers to a heteroaryl group containing 5 to 18 carbon atoms, preferably a heteroaryl group having 5 to 14 carbon atoms, more preferably a heteroaryl group having 5 to 10 carbon atoms, and the heterocyclic group may optionally be further substituted. Suitable examples include, but are not limited to: thiophene, furanyl, pyrrole, imidazolyl, diazolyl, triazolyl, pyridyl, bipyridyl, pyrimidinyl, triazine, acridine, pyridazinyl, quinolinyl, isoquinolinyl, quinazole Linyl, quinoxalinyl, phthalazinyl, pyridinylpyrimidinyl, pyridinylpyrazinyl, benzothiopheneyl, benzofuranyl, indolyl, pyrroloimidazolyl, pyrrolopyrrolyl, thienopyrrolyl, thienopyrrolyl, furanolyl, furanolyl, thienofuranyl, benzoisoxazolyl, benzoisothiazolyl, benzoimidazolyl, o-diazonyl, phenanthrynyl, primidyl, quinazolinoneyl, dibenzothiopheneyl, dibenzofuranyl, carbazoleyl and their derivatives.

[0023] In this application, "alkyl" can mean straight-chain alkyl and / or branched alkyl. Cycloalkyl refers to cyclic alkyl. Phrases containing this term, such as "C1 to C30 alkyl", refer to alkyl groups containing 1 to 30 carbon atoms, and each time it appears, it can independently be C1 alkyl, C2 alkyl, C3 alkyl, C4 alkyl, C5 alkyl, C6 alkyl, C7 alkyl, C8 alkyl, C9 alkyl, C10 alkyl, C11 alkyl, C12 alkyl, C13 alkyl, C14 alkyl, C15 alkyl, C16 alkyl, C17 alkyl, C18 alkyl, C19 alkyl, C20 alkyl, C21 alkyl, C22 alkyl, C23 alkyl, C24 alkyl, C26 alkyl, C27 alkyl, C28 alkyl, C29 alkyl, or C30 alkyl. Non-limiting examples of alkyl groups include methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, isobutyl, 2-ethylbutyl, 3,3-dimethylbutyl, n-pentyl, isopentyl, neopentyl, tert-pentyl, cyclopentyl, 1-methylpentyl, 3-methylpentyl, 2-ethylpentyl, 4-methyl-2-pentyl, n-hexyl, 1-methylhexyl, 2-ethylhexyl, 2-butylhexyl, cyclohexyl, 4-methylcyclohexyl, 4-tert-butylcyclohexyl, n-heptyl, 1-methylheptyl, 2,2-dimethylheptyl, 2-ethylheptyl, 2-butylheptyl, n-octyl, tert-octyl, 2-ethyloctyl 2-Butyloctyl, 2-hexyloctyl, 3,7-dimethyloctyl, cyclooctyl, n-nonyl, n-decyl, adamantyl, 2-ethyldecyl, 2-butyldecyl, 2-hexyldecyl, 2-octyldecyl, n-undecyl, n-dodecyl, 2-ethyldodecyl, 2-butyldodecyl, 2-hexyldodecyl, 2-octyldodecyl, n-tridecyl, n-tetradecyl, n-pentadecanyl, n-hexadecyl, 2-ethylhexadecyl, 2-butylhexadecyl, n-heptadecyl, n-heptadecyl, n-octadecyl, n-nonadecanyl, n-eicosyl, n-timodecyl, n-timodecyl, n-pentadecanyl, n-triadecyl, etc.

[0024] In this application, "alkoxy" refers to a group with the structure "-O-alkyl", that is, an alkyl group as defined above connected to other groups via an oxygen atom. Suitable examples of phrases containing this term include, but are not limited to: methoxy (-O-CH3 or -OMe), ethoxy (-O-CH2CH3 or -OEt), and tert-butoxy (-OC(CH3)3 or -OtBu). It is understood that "alkathiol" refers to a group with the structure "-S-alkyl", "aryloxy" refers to a group with the structure "-O-aryl", and "heteroaryloxy" refers to a group with the structure "-O-heteroaryl".

[0025] In this application, "amino group" refers to an amine derivative having the structural feature of the formula -N(X)2, wherein each "X" is independently H, a substituted or unsubstituted alkyl group, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted heterocyclic group, etc. Non-limiting types of amino groups include -NH2, -N(alkyl)2, -NH(alkyl), -N(cycloalkyl)2, -NH(cycloalkyl), -N(heterocyclic)2, -NH(heterocyclic), -N(aryl)2, -NH(aryl), -N(alkyl)(aryl), -N(alkyl)(heterocyclic), -N(cycloalkyl)(heterocyclic), -N(aryl)(heteroaryl), -N(alkyl)(heteroaryl), etc. When both X's are hydrogen, -N(X)2 is a primary amino group; when only one of the two X's is hydrogen, -N(X)2 is a secondary amino group; when neither X's is hydrogen, -N(X)2 is a tertiary amino group.

[0026] In this application, unless otherwise defined, hydroxyl group refers to -OH, halogen group refers to -F, -Cl, -Br or -I, carboxyl group refers to -COOH, nitro group refers to -NO2, sulfonic acid group refers to "-SO3H", aldehyde group refers to -CHO, mercapto group refers to -SH, and cyano group refers to -C≡N.

[0027] The terms “combinations thereof,” “any combination thereof,” and “any combination thereof” as used in this application include all suitable combinations of any two or more of the listed items.

[0028] This application discloses a light-emitting device 100, which may be, for example, an organic light-emitting device (OLED), a quantum dot light-emitting device (QLED), etc. Please refer to... Figure 1 The light-emitting device 100 includes a stacked anode 10, a light-emitting layer 30, an electronic functional layer 60, and a cathode. The cathode is made of a metallic material and a thiadiazole compound, wherein the thiadiazole compound has the structure shown in formula (I).

[0029] Equation (Ⅰ):

[0030] Where n is 1 or 2;

[0031] Each time R appears, it is independently selected from one or more combinations of deuterium, nitro, amino, halogen, hydroxyl, carboxyl, sulfonic acid, aldehyde, mercapto, cyano, C1-C30 alkyl, C3-C30 cycloalkyl, C1-C30 alkoxy, C1-C30 alkylthio, C6-C30 aryl, C5-C30 heteroaryl, C6-C30 aryloxy, and C5-C30 heteroaryloxy.

[0032] It is understood that thiadiazole compounds can have one of the structures shown in the following structural formulas:

[0033]

[0034] R1 and R2 represent two R substituents. R1 and R2 can be the same or different, and each can be independently selected from one or more combinations of deuterium, nitro, amino, halogen, hydroxyl, carboxyl, sulfonic acid, aldehyde, mercapto, cyano, C1-C30 alkyl, C3-C30 cycloalkyl, C1-C30 alkoxy, C1-C30 alkylthio, C6-C30 aryl, C5-C30 heteroaryl, C6-C30 aryloxy, and C5-C30 heteroaryloxy.

[0035] Furthermore, in some embodiments, each occurrence of R is independently selected from one or more combinations of amino, halogen, mercapto, C1-C30 alkyl, C1-C30 alkoxy, C1-C30 alkylthio, and C6-C30 aryl groups. When selected from the above groups, thiadiazole compounds are more widely available and easier to obtain.

[0036] In some specific embodiments, the thiadiazole compounds may include, but are not limited to, one or more of 2-amino-1,3,4-thiadiazole (CAS: 4005-51-0), 2,5-dithio-1,3,4-thiadiazole (CAS: 1072-71-5), 2-amino-5-(4-chlorophenyl)-1,3,4-thiadiazole (CAS: 28004-62-8), 2-amino-5-methylthio-1,3,4-thiadiazole (CAS: 5319-77-7), 2-amino-5-trifluoromethyl-1,3,4-thiadiazole (CAS: 10444-89-0), and 5-methyl-1,3,4-thiadiazole-2-thiol (CAS: 29490-19-5). The structural formulas of the above compounds are as follows:

[0037]

[0038] In some embodiments, the metal material may be a commonly used metal electrode material in the art, such as one or more of Ag, Al, Cu, Mo, Au, Pt, Si, Ca, Mg and Ba. The above metal materials have good electrical conductivity, which helps to improve the light-emitting performance of the device.

[0039] The inventors discovered that when the electronic functional layer 60 uses N-type inorganic semiconductors such as metal oxides, during the high-temperature and high-voltage power-on test of the light-emitting device 100, the metal oxide nanoparticles in the electronic functional layer 60 easily react with the metal electrodes, causing some of the N-type inorganic semiconductors to be converted into metal elements. At the same time, the metal electrodes are oxidized to form metal oxides. This results in two consequences: firstly, since the electronic functional layer 60 and the light-emitting layer 30 are in direct contact, the conversion of some of the N-type inorganic semiconductors into metal elements can easily quench the light-emitting layer 30; secondly, the decreased conductivity of the oxidized metal electrodes also leads to poorer electron injection, which in turn affects the light-emitting performance of the device, causing a rapid decline in the device's light-emitting performance and lifespan.

[0040] The light-emitting device 100 proposed in this application introduces thiadiazole compounds into the cathode, which helps to reduce the reactivity of the metal electrode, thereby reducing the probability of the metal electrode reacting with the metal oxide in the electronic functional layer 60, which helps to improve the luminous efficiency of the light-emitting device 100 and extend the device's lifespan.

[0041] The cathode can be a doped electrode 21 with a single film layer structure, or a composite cathode 22 formed by stacking multiple film layers.

[0042] In some embodiments, the cathode is a doped electrode 21, and the material of the doped electrode 21 is a mixture of the metal material and the thiadiazole compound. The doped electrode 21 can be prepared by physical deposition method, in which the thiadiazole compound is coordinated with the metal atoms of the metal material in the doped electrode 21 prepared by this method; specifically, the N or S atoms in the thiadiazole compound can act as coordinating atoms to form coordinate bonds with the metal atoms of the metal material.

[0043] In some embodiments, the mass ratio of the thiadiazole compound to the metal material in the doped electrode 21 is 1 to 10:100; for example, it can be 1:100, 2:100, 3:100, 4:100, 5:100, 6:100, 7:100, 8:100, 9:100, 10:100, or any two of the above values. Controlling it within this range helps to effectively reduce the reactivity of the metal material while regulating the conductivity of the doped electrode 21, thus improving the carrier transport performance of the device. Further, the mass ratio of the thiadiazole compound to the metal material can be 3 to 8:100, which helps to better balance the improvement effect on the conductivity of the doped electrode 21 and the carrier transport performance of the device.

[0044] In some embodiments, the thickness of the doped electrode 21 is 20–120 nm. For example, it can be 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, 100 nm, 110 nm, 120 nm, or any range between two of these values. In this document, the thickness of the film can be obtained by a profilometer.

[0045] In other embodiments, the cathode is a composite cathode 22. See also... Figure 2 The composite cathode 22 includes an electrode layer 221 and an interface layer 222. The interface layer 222 is disposed between the electrode layer 221 and the electronic functional layer 60. The electrode layer 221 is made of the aforementioned metallic material, and the interface layer 222 is made of the aforementioned thiadiazole compound. The interface layer 222 covers the side of the electrode layer 221 facing the electronic functional layer 60, forming a dense protective film on this side of the electrode layer 221. This isolates the metallic elements in the electrode layer 221 from the material of the electronic functional layer 60 during high-temperature and high-pressure energization, reducing the risk of reaction between the two.

[0046] The interface layer 222 can be prepared by solution method or chemical method, or by physical coating method. In the composite cathode 22 prepared by physical coating method, at the interface between the interface layer 222 and the electrode layer 221, the thiadiazole compound can coordinate with the metal atoms of the metal material; specifically, the N or S atoms in the thiadiazole compound can act as coordinating atoms to form coordinate bonds with the metal atoms of the metal material.

[0047] In some embodiments, the thickness of the electrode layer 221 is 20–120 nm. For example, it can be 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, 100 nm, 110 nm, 120 nm, or any range between two of the above values.

[0048] In some embodiments, the thickness of the interface layer 222 is 1–5 nm; for example, it can be 1 nm, 2 nm, 3 nm, 4 nm, 5 nm, or any two of the above values. By controlling it within this range, the reaction between the electrode layer 221 and the electronic functional layer 60 can be effectively isolated while ensuring carrier transport within the device.

[0049] In some embodiments, the electronic functional layer 60 includes an electron transport layer. In some embodiments, the thickness of the electron transport layer can be 20–60 nm, for example, 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, or any value between any two of the above.

[0050] The electron transport layer can be fabricated using N-type inorganic semiconductors with electron transport properties commonly used in the art. Accordingly, in some embodiments, the electron transport layer may include an inorganic layer 61. The material of the inorganic layer 61 may include, but is not limited to, at least one of metal oxides, doped metal oxides, group IIA-VIA semiconductor materials, group IIIA-VA semiconductor materials, and group IB-IIIA-VIA semiconductor materials. The metal oxides include one or more of ZnO, TiO2, and SnO2. The doped metal oxides include one or more of ZnO, TiO2, and SnO2. The doping elements include one or more of Al, Mg, Li, In, and Ga. The group IIA-VIA semiconductor materials include at least one of ZnS, ZnSe, and CdS. The group IIIA-VA semiconductor materials include at least one of InP and GaP. The group IB-IIIA-VIA semiconductor materials include at least one of CuInS and CuGaS. The aforementioned N-type inorganic semiconductors have high electron mobility, which can promote electron injection. In this embodiment, the thickness of the inorganic layer 61 can be 20 to 60 nm, for example, it can be 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, or any value between any two of the above.

[0051] To further prevent the electron transport layer material from reacting with the metallic material, in some embodiments, the electron transport layer may include an organic layer 62. The organic layer 62 may be made of an N-type organic compound with electron transport properties, such as, but not limited to, TPBi (1,3,5-tris(N-phenylbenzimidazol-2-yl)benzene), BCP (2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline), Bphen (4,7-diphenyl-1,10-phenanthroline), OXD-7 (1,3-bis[5-(4-yl)-phenylene oxide), etc. One or more of the following N-type organic compounds are used: (-tert-butylphenyl)-2-[1,3,4]oxadiazolyl]benzene, TpPyPB(1,3,5-tris(4-pyridin-3-ylphenyl)benzene), TmPyPB(1,3,5-tris(3-pyridin-3-ylphenyl)benzene), Bpy-OXD(1,3-bis[2-(2,2-bipyridin-6-yl)-1,3,4-oxadiazol-5-yl]benzene), DPVBi(2,5-diphenyl-1,3,4-oxadiazole), and BND(2,5-bis(1-naphthyl)-1,3,4-oxadiazole). Using these N-type organic compounds can reduce the risk of reaction between N-type organic compounds and metallic materials, avoid the generation of elemental metals, prevent the quenching of the luminescent layer 30 material, and avoid damage to the metallic material. In this embodiment, the thickness of the organic layer 62 can be 20 to 60 nm, for example, it can be 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, or any value between any two of the above.

[0052] In other embodiments, the electron transport layer comprises a stacked organic layer 62 and an inorganic layer 61, see [link to relevant documentation]. Figure 3 The inorganic layer 61 is disposed between the organic layer 62 and the light-emitting layer 30. The inorganic layer 61 has a high electron mobility, which promotes electron injection. Simultaneously, the organic layer 62 prevents the inorganic layer 61 from directly contacting the cathode, helping to reduce the risk of material reaction between the inorganic layer 61 and the metal material. Therefore, the electron transport layer can have both high electron mobility and be less prone to reaction with the metal material. In this embodiment, the thickness of the electron transport layer can be 20–60 nm, for example, 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, or any value between any two of these values. Furthermore, the thickness ratio of the organic layer 62 to the inorganic layer 61 in the electron transport layer can be 30–40:1; for example, 30:1, 31:1, 32:1, 33:1, 34:1, 35:1, 36:1, 37:1, 38:1, 39:1, 40:1, or any value between any two of these values. In this way, the functions of organic layer 62 and inorganic layer 61 can be effectively utilized, and the matching between electron transport layer and other film layers in light-emitting device 100 can be improved, thereby improving the light-emitting performance and lifespan of the device.

[0053] Please see Figure 4 To further improve electron injection and increase electron migration, in some embodiments, the electronic functional layer 60 may further include an electron injection layer 63 disposed between the electron transport layer and the cathode. The material of the electron injection layer 63 may be one or more of organic compounds and fullerenes, such as lithium 8-hydroxyquinoline (Liq), lithium 2-methyl-8-hydroxyquinoline (LiMeq), and fullerene C60. In some embodiments, the thickness of the electron injection layer 63 may be 0.5–20 nm; for example, it may be 0.5 nm, 0.6 nm, 0.8 nm, 1 nm, 1.3 nm, 1.5 nm, 1.7 nm, 2 nm, 2.2 nm, 2.5 nm, 3 nm, 4 nm, 5 nm, 6 nm, 7 nm, 8 nm, 9 nm, 10 nm, 11 nm, 12 nm, 13 nm, 14 nm, 15 nm, 16 nm, 17 nm, 18 nm, 19 nm, 20 nm, or any value between any two of the above. Furthermore, in some other embodiments, the thickness of the electron injection layer 63 can be 0.5 to 2 nm. Setting an extremely thin electron injection layer 63 helps to improve the injection barrier while reducing resistance, which is more conducive to increasing electron injection.

[0054] The anode 10 may include a doped metal oxide particle electrode, a metal-metal oxide composite electrode, a graphene electrode, a carbon nanotube electrode, a metal electrode, or an alloy electrode. The material of the doped metal oxide particle electrode is selected from one or more of indium-doped tin oxide, fluorine-doped tin oxide, antimony-doped tin oxide, aluminum-doped zinc oxide, gallium-doped zinc oxide, indium-doped zinc oxide, magnesium-doped zinc oxide, and aluminum-doped magnesium oxide. The metal-metal oxide composite electrode is selected from AZO / Ag / AZO, AZO / Al / AZO, ITO / Ag / ITO, etc. The electrode materials are selected from one or more of Ag, Al, Cu, Mo, Au, Pt, Si, Ca, Mg, and Ba, including ITO / Al / ITO, ZnO / Ag / ZnO, ZnO / Al / ZnO, TiO2 / Ag / TiO2, TiO2 / Al / TiO2, ZnS / Ag / ZnS, and ZnS / Al / ZnS. The " / " indicates a stacked structure; for example, the composite electrode AZO / Ag / AZO represents a three-layered composite electrode consisting of an AZO layer, an Ag layer, and an AZO layer. The thickness of the anode 10 can be 20–120 nm.

[0055] In some embodiments, the thickness of the light-emitting layer 30 is 15nm to 60nm; for example, it can be 15nm, 20nm, 30nm, 40nm, 50nm, 60nm, or any two of the above values.

[0056] The material of the light-emitting layer 30 may include organic light-emitting materials or quantum dots. The organic light-emitting material is an organic material known in the art for use in the light-emitting layer 30, for example, it may be selected from, but is not limited to, at least one of diaromatic anthracene derivatives, stilbene aromatic derivatives, pyrene derivatives or fluorene derivatives, blue-emitting TBPe fluorescent materials, green-emitting TTPA fluorescent materials, orange-emitting TBRb fluorescent materials, and red-emitting DBP fluorescent materials. The quantum dot is an inorganic quantum dot known in the art for use in the light-emitting layer 30, for example, one of red quantum dots, green quantum dots, and blue quantum dots.The quantum dots can be selected from, but are not limited to, at least one of single-structure quantum dots, core-shell quantum dots, and perovskite semiconductor materials. The shell of the core-shell quantum dot includes one or more layers. The material of the single-structure quantum dot, the core material of the core-shell quantum dot, and the shell material of the core-shell quantum dot respectively include at least one of group II-VI compounds, group IV-VI compounds, group III-V compounds, and group I-III-VI compounds. The group II-VI compounds include CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe, CdSeS, CdSeTe, and CdSTe. At least one of the following: ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, CdZnS, CdZnSe, CdZnTe, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, HgZnTe, CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe, and HgZnSTe; the IV-VI group compounds include SnS, SnSe, SnTe, PbS, PbSe, PbTe, SnSeS, SnSeTe, S At least one of nSTe, PbSeS, PbSeTe, PbSTe, SnPbS, SnPbSe, SnPbTe, SnPbSSe, SnPbSeTe, and SnPbSTe; the III-V compound includes at least one of GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, InSb, GaNP, GaNAs, GaNSb, GaPAs, GaPSb, AlNP, AlNAs, AlNSb, AlPAs, AlPSb, InNP, InNAs, InNSb, InPAs, InPSb, and GaAlNP. The perovskite semiconductor material is selected from at least one of GaAlNAs, GaAlNSb, GaAlPAs, GaAlPSb, GaInNP, GaInNAs, GaInNSb, GaInPAs, GaInPSb, InAlNP, InAlNAs, InAlNSb, InAlPAs, and InAlPSb; the I-III-VI group compounds include at least one of CuInS2, CuInSe2, and AgInS2; the perovskite semiconductor material is selected from doped or undoped inorganic perovskite semiconductors or organic-inorganic hybrid perovskite semiconductors; the general structural formula of the inorganic perovskite semiconductor is AMX3, where A is Cs. + Ion, M is a divalent metal cation selected from Pb 2+ Sn 2+Cu 2+ Ni 2+ Cd 2+ Cr 2+ Mn 2+ Co 2+ Fe 2+ 、Ge 2+ Yb 2+ Eu 2+ At least one of them, where X is a halide anion selected from Cl. - ,Br - I - At least one of the following; the general structural formula of the organic-inorganic hybrid perovskite semiconductor is BMX3, wherein B is an organic amine cation selected from CH3(CH2). n-2 NH3 + Or [NH3(CH2)] n NH3] 2+ Where n≥2, M is a divalent metal cation selected from Pb 2+ Sn 2+ Cu 2+ Ni 2+ Cd 2+ Cr 2+ Mn 2+ Co 2+ Fe 2+ 、Ge 2+ Yb 2+ Eu 2+ At least one of them, where X is a halide anion selected from Cl. - ,Br - I - At least one of them.

[0057] As an example, the core-shell structured quantum dots may be selected from, but are not limited to, at least one of CdZnSe / CdZnSe / ZnSe / CdZnS / ZnS, CdZnSe / CdZnSe / CdZnS / ZnS, CdSe / CdSeS / CdS, InP / ZnSeS / ZnS, CdZnSe / ZnSe / ZnS, CdSeS / ZnSeS / ZnS, CdSe / ZnS, CdSe / ZnSe / ZnS, ZnSe / ZnS, ZnSeTe / ZnS, CdSe / CdZnSeS / ZnS, and InP / ZnSe / ZnS. It should be noted that for the aforementioned materials consisting of single-structure quantum dots, or core-shell structure quantum dots, or shell-structure quantum dots, the provided chemical formulas only indicate the elemental composition, not the content of each element. For example, CdZnSe only indicates that it is composed of three elements: Cd, Zn, and Se. If the content of each element were specified, it would correspond to Cd...x Zn 1-x Se, where 0 < x < 1. It can be understood that the core material and the materials of each shell layer of the core-shell structure quantum dots are expressed by connecting with " / ", and the order from left to right is the material types of the quantum dots from the inside to the outside: core material / first shell layer material / Nth shell layer material, where N is an integer greater than or equal to 1; for example, CdSe / CdZnSeS / ZnS represents a core-shell structure quantum dot with two shell layers, its core material is CdSe, the material of the first shell layer coated on the core is CdZnSeS, and the material of the second shell layer coated outside the first shell layer is ZnS.

[0058] In some embodiments, the light-emitting device 100 further includes a hole functional layer disposed between the light-emitting layer 30 and the anode 10. The hole functional layer includes one or both of a hole injection layer 50 and a hole transport layer 40. When the hole functional layer simultaneously includes the hole injection layer 50 and the hole transport layer 40, the hole injection layer 50 is located between the hole transport layer 40 and the anode 10.

[0059] In some embodiments, the hole transport layer 40 may be made of an organic material with hole transport capability, including but not limited to 4,4'-N,N'-dicarbazolyl-biphenyl (CBP), poly[(9,9'-dioctylfluorene-2,7-diyl)-co-(4,4'-(N-(4-sec-butylphenyl)diphenylamine))] (TFB), 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 (TPD), N,N'-bis(3-methylphenyl)-N,N'-bis(phenyl)-spiro(spiro-TPD), N,N'-bis(4-(N,N'-diphenyl-amino)phenyl)-N,N'-diphenylbenzidine (DNTP) D), 4,4',4”-tris(N-3-methylphenyl-N-phenylamino)triphenylamine (m-MTDATA), poly(p-)phenylenevinylene (PPV), poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV), poly[2-methoxy-5-(3',7'-dimethyloctyloxy)-1,4-phenylenevinylene] (MOMO-PPV), 4,4'-bis(p-carbazolyl)-1,1'-biphenyl compounds, N,N,N',N'-tetraarylbenzidine, PEDOT:PSS, poly(N-vinylcarbazole) (PVK), polymethacrylate, poly(9,9-octylfluorene), N,N'-di(naphthyl-1-yl)-N,N'-diphenylbenzidine (NPB), spiroNPB, doped graphene, and undoped graphene, or one or more of these. The material of the hole transport layer 40 can also be selected from inorganic materials with hole transport capability, including but not limited to doped or undoped metal oxides, such as one or more of doped or undoped NiO, WO3, MoO3, and CuO. The material of the hole transport layer 40 described above has good compatibility and energy level matching with the composite material.

[0060] In some embodiments, the thickness of the hole transport layer 40 can be 20 to 60 nm, for example, 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, or any value between any two of the above.

[0061] In some embodiments, the hole injection layer 50 can be prepared using materials commonly used in the art that have hole injection capabilities, such as, but not limited to, poly(3,4-ethylenedioxythiophene) (PEDOT), poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid (PEDOT:PSS), 2,3,5,6-tetrafluoro-7,7',8,8'-tetracyanoquinone-dimethylethane (F4-TCNQ), 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazabenzphenanthrene (HATCN), copper polyester carbonate (CuPc), transition metal oxides, and metal chalcogenides; wherein the transition metal oxides include one or more of NiO, MoO2, WO3, and CuO; and the metal chalcogenides include one or more of MoS2, MoSe2, WS3, WSe3, and CuS. In some embodiments, the thickness of the hole injection layer 50 can be 20 to 60 nm, for example, 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, or any value between any two of the above.

[0062] It is understood that the light-emitting device 100 can be an upright device, whose film structure may include an anode 10, a hole injection layer 50, a hole transport layer 40, a light-emitting layer 30, an electronic functional layer 60, and a cathode stacked in sequence, or it can be an inverted device, whose film structure may include a cathode, an electronic functional layer 60, a light-emitting layer 30, a hole transport layer 40, a hole injection layer 50, and an anode 10 stacked in sequence.

[0063] It is understood that the light-emitting device 100 may also be provided with some functional layers that are conventionally used in the light-emitting device 100 and help to improve the device performance, such as electron blocking layer, hole blocking layer, interface modification layer, etc.

[0064] It is understood that the materials of each layer of the light-emitting device 100 can be adjusted according to the photoelectric requirements of the light-emitting device 100.

[0065] This application also proposes a method for fabricating a light-emitting device 100, which can produce the aforementioned light-emitting device 100. The method for fabricating the light-emitting device 100 may include the following steps:

[0066] S1 provides the first electrode;

[0067] S2, a functional layer is prepared on the first electrode, the functional layer including a stacked electronic functional layer 60 and a light-emitting layer 30;

[0068] S3, a second electrode is disposed on the side of the functional layer opposite to the first electrode;

[0069] Wherein, the first electrode is selected from one of the anode 10 and the cathode, and the second electrode is selected from the other of the anode 10 and the cathode; the cathode is prepared by: providing a thiadiazole compound and a metallic material; depositing the thiadiazole compound and the metallic material to obtain the cathode;

[0070] The thiadiazole compounds have the structure shown in formula (Ⅰ);

[0071] Equation (Ⅰ):

[0072] Where n is 1 or 2;

[0073] Each time R appears, it is independently selected from one or more combinations of deuterium, nitro, amino, halogen, hydroxyl, carboxyl, sulfonic acid, aldehyde, mercapto, cyano, C1-C30 alkyl, C3-C30 cycloalkyl, C1-C30 alkoxy, C1-C30 alkylthio, C6-C30 aryl, C5-C30 heteroaryl, C6-C30 aryloxy, and C5-C30 heteroaryloxy.

[0074] In this configuration, the first electrode is selected from either the anode 10 or the cathode, and the second electrode is selected from the other of the anode 10 and the cathode. In actual fabrication, multiple film layers can be sequentially fabricated according to the stacking order of the target device's film layers to obtain the light-emitting device 100. For example, when the target device is structured as follows: anode 10, hole injection layer 50, hole transport layer 40, light-emitting layer 30, electronic functional layer 60, and cathode are stacked sequentially from bottom to top, the first electrode is the anode 10, and the second electrode is the cathode. Correspondingly, the anode 10, hole injection layer 50, hole transport layer 40, interface layer 222, light-emitting layer 30, electronic functional layer 60, and cathode can be fabricated sequentially to obtain the target device. Conversely, when the target device is constructed by stacking the cathode, electron functional layer 60, light-emitting layer 30, hole transport layer 40, hole injection layer 50, and anode 10 sequentially from bottom to top, the first electrode is the cathode and the second electrode is the anode 10. The cathode, electron functional layer 60, light-emitting layer 30, hole transport layer 40, hole injection layer 50, and anode 10 can be fabricated sequentially to obtain the target device.

[0075] The various film layers in the light-emitting device 100 provided in this application, including the anode 10, hole injection layer 50, hole transport layer 40, light-emitting layer 30, electronic functional layer 60, cathode, and other film layers, can all be prepared using conventional techniques in the art, such as chemical or physical methods. Chemical methods include chemical vapor deposition, continuous ion layer adsorption and reaction, anodic oxidation, electrolytic deposition, and co-precipitation. Physical methods include physical deposition and solution methods. Physical deposition methods include thermal evaporation deposition, electron beam evaporation deposition, magnetron sputtering, multi-arc ion deposition, physical vapor deposition, atomic layer deposition, pulsed laser deposition, etc.; solution methods can include spin coating, printing, inkjet printing, blade coating, dip coating, immersion coating, spraying, roller coating, casting, slot coating, and strip coating, etc.

[0076] In some embodiments, the preparation of the cathode may include the preparation of a doped electrode 21. Specifically, the steps for preparing the doped electrode 21 include: depositing a mixture of the thiadiazole compound and the metal material to obtain the doped electrode 21. In actual preparation, the mixture of the thiadiazole compound and the metal material can be deposited by physical deposition, specifically by vapor deposition. When the doped electrode 21 is prepared by vapor deposition, the vapor deposition conditions can be: the vapor deposition process can be carried out at 10... -5 ~10 -6 The process is carried out under a vacuum of Pa, and the temperature at which the vaporization material is induced to vaporize (hereinafter referred to as the substrate temperature) can be set to 400–450 °C, with a vaporization rate of 0.5–1 Å / s. The mass ratio of the thiadiazole compound used in the vaporization process to the metal material can be 1–10:100.

[0077] In other embodiments, the fabrication of the cathode may include the fabrication of a composite cathode 22, which includes: depositing the thiadiazole compound to obtain an interface layer 222; and depositing the metal material to obtain an electrode layer 221. It is understood that the order of fabrication of the interface layer 222 and the electrode layer 221 can be adjusted according to the stacking order of these two layers in the target device. For example, when the cathode is a composite cathode 22 and the device is an inverted device, the electrode layer 221 can be fabricated first, followed by the interface layer 222; when the device is an upright device, the interface layer 222 can be fabricated first, followed by the electrode layer 221.

[0078] The electrode layer 221 is prepared by the following steps: depositing the metal material to obtain the electrode layer 221. In actual preparation, the metal material can be deposited using a physical deposition method, specifically, by vapor deposition. When using vapor deposition to prepare the doped electrode 21, the vapor deposition conditions can be: the vapor deposition process can be carried out at 10...-5 ~10 -6 The process is carried out under a vacuum of Pa, with the substrate temperature set to 400–450 °C and the evaporation rate to 0.5–1 Å / s.

[0079] The interface layer 222 can be prepared by the following steps: depositing the thiadiazole compound to obtain the electrode layer 221. In actual preparation, the thiadiazole compound can be deposited using a solution method, specifically including: dispersing the thiadiazole compound in a solvent to obtain a mixed solution with a concentration of 5–15 mg / mL; depositing the mixed solution; vacuum drying to remove the solvent and form a solid film; and then annealing at 80–100°C for 10–30 min to obtain the interface layer 222. The solvent can be one or more of ethanol, dimethylformamide (DMF), and methanol, among others. It is understood that the interface layer 222 can also be prepared by vapor deposition.

[0080] The electronic functional layer 60 includes an electron transport layer, and correspondingly, the preparation of the electronic functional layer 60 includes the preparation of the electron transport layer. When the electron transport layer includes one or both of an inorganic layer 61 and an organic layer 62, it can be prepared according to the film structure of the target electron transport layer. The inorganic layer 61 can be prepared by a solution method. Specifically, the material of the inorganic layer 61 can be dispersed in an alcohol solvent to form a mixed solution with a concentration of 5–30 mg / mL. The mixed solution is deposited, vacuum dried to form a solid film, and then annealed at 80–100°C for 10–30 min to obtain the inorganic layer 61. The alcohol solvent can include, but is not limited to, one or more of methanol, ethanol, isopropanol, n-butanol, and pentanol. The organic layer 62 can be prepared by a solution method or by vapor deposition. When prepared by vapor deposition, the vapor deposition conditions can be: the vapor deposition process can be carried out within 10 minutes. -5 ~10 -6 The process is carried out under a vacuum of Pa, with the substrate temperature set to 400–450 °C and the evaporation rate to 0.5–1 Å / s.

[0081] The specific types of thiadiazole compounds, metallic materials, organic layer 62 materials, inorganic layer 61 materials, and electron injection layer 63 materials involved in the above steps can all be referred to the above description and will not be repeated here.

[0082] Furthermore, this application also relates to a display device, which includes the light-emitting device 100 provided in 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.

[0083] 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.

[0084] Example 1

[0085] This embodiment provides a QLED device with a structure of ITO (100nm) / PEDOT:PSS (50nm) / TFB (50nm) / QD (20nm) / ETL (ZnO, 40nm) / doped electrode (20nm).

[0086] The fabrication method of the device in this embodiment is as follows:

[0087] Step S1: After cleaning and drying the ITO substrate, treat it in a UV ozone cleaner for 15 minutes to serve as the anode.

[0088] Step S2: Spin-coat an aqueous solution of PEDOT:PSS onto an ITO substrate and heat at 150°C for 15 minutes to obtain a hole injection layer.

[0089] Step S3: Spin-coat a chlorobenzene solution of TFB (concentration of 8 mg / mL) onto the hole injection layer, and then anneal it on a 120°C hot plate for 10 min to obtain the hole transport layer.

[0090] Step S4: Spin-coat a hexane solution of CdSe / CdZnSeS / ZnS quantum dots with a concentration of 20 mg / mL onto the hole transport layer, and then anneal it on a 100°C heating plate for 10 min to obtain the light-emitting layer.

[0091] Step S5: Spin-coat an ethanol solution of ZnO (concentration 5 mg / mL) onto the luminescent layer, then anneal it on a hot plate at 140°C for 30 min to obtain the inorganic layer. The inorganic layer constitutes the electronic functional layer.

[0092] Step S6: Ag and a thiadiazole compound (2,5-dithio-1,3,4-thiadiazole) are deposited by thermal evaporation at a mass ratio of 100:5. During evaporation, the substrate temperature is 400℃ and the vacuum degree is no higher than 5 × 10⁻⁶. -6 Pa, speed is The cathode is obtained by vapor deposition for 400 seconds, and finally packaged to obtain a positive quantum dot light-emitting diode.

[0093] Example 2

[0094] This embodiment is basically the same as Embodiment 1, except that in this embodiment, the electronic functional layer is composed of an organic layer, and the material of the organic layer is Bphen. Accordingly, step S5 is changed to: depositing Bphen on the light-emitting layer at a substrate temperature of 400°C and a vacuum degree not exceeding 5×10⁻⁶. -6 Pa, speed is The organic layer is obtained by vapor deposition for 400 seconds. The organic layer constitutes the electronic functional layer.

[0095] Example 3

[0096] This embodiment is basically the same as Embodiment 1, except that in this embodiment, the electronic functional layer is composed of an inorganic layer (thickness approximately 1 nm) and an organic layer (thickness approximately 39 nm). The material of the inorganic layer is ZnO, and the material of the organic layer is Bphen. Accordingly, step S5 is changed to:

[0097] An ethanol solution of ZnO (5 mg / mL) was spin-coated onto the luminescent layer, followed by annealing at 140°C for 30 min to obtain the inorganic layer. An ethanol solution of Bphen (30 mg / mL) was then spin-coated onto the inorganic layer, followed by annealing at 80°C for 30 min to obtain the organic layer. The inorganic and organic layers together constitute the electronic functional layer.

[0098] Example 4

[0099] This embodiment is basically the same as Embodiment 3, except that in this embodiment, the electronic functional layer also includes an electron injection layer disposed between the organic layer and the cathode. Correspondingly, in step S5, after preparing the organic layer, the method further includes: depositing a 0.8 nm thick Liq layer on the surface of the organic layer as the electron injection layer. During the deposition, the substrate temperature is 400°C and the vacuum degree is not higher than 1×10⁻⁶. - 3 Pa, speed is Evaporation for 80 seconds.

[0100] Example 5

[0101] This embodiment is basically the same as Example 4, except that in this embodiment, the thiadiazole compound is replaced with 2-amino-5-methylthio-1,3,4-thiadiazole.

[0102] Example 6

[0103] This embodiment is basically the same as Example 4, except that in this embodiment, the thiadiazole compound is replaced with 5-methyl-1,3,4-thiadiazole-2-thiol.

[0104] Example 7

[0105] This embodiment is basically the same as Embodiment 4, except that the mass ratio of Ag to thiadiazole compounds is changed to 100:1 in this embodiment.

[0106] Example 8

[0107] This embodiment is basically the same as Embodiment 4, except that the mass ratio of Ag to thiadiazole compounds is changed to 100:10 in this embodiment.

[0108] Example 9

[0109] This embodiment is basically the same as Embodiment 4, except that the mass ratio of Ag to thiadiazole compounds is changed to 100:11 in this embodiment.

[0110] Example 10

[0111] This embodiment is basically the same as Embodiment 4, except that in this embodiment, the cathode is a composite cathode, consisting of a 1nm thick interface layer and a 19nm thick electrode layer. Step S6 is changed to:

[0112] A thiadiazole compound (2,5-dithio-1,3,4-thiadiazole) was dispersed in DMF to prepare a mixed solution with a concentration of 10 mg / mL. The mixed solution was spin-coated onto the electronic functional layer, vacuum dried to form a solid film, and then annealed at 80 °C for 10 min to obtain the interface layer.

[0113] Ag is deposited by thermal evaporation. During evaporation, the substrate temperature is 400℃ and the vacuum degree is no higher than 5×10⁻⁶. -6 Pa, speed is An electrode layer is obtained, and the electrode layer and the interface layer together constitute the cathode. Finally, it is packaged to obtain a positive quantum dot light-emitting diode.

[0114] Example 11

[0115] This embodiment is basically the same as embodiment 10, except that in this embodiment, the cathode is a composite cathode, consisting of a 3nm thick interface layer and a 17nm thick electrode layer.

[0116] Example 12

[0117] This embodiment is basically the same as embodiment 10, except that in this embodiment, the cathode is a composite cathode, consisting of a 5nm thick interface layer and a 15nm thick electrode layer.

[0118] Example 13

[0119] This embodiment is basically the same as embodiment 10, except that in this embodiment, the cathode is a composite cathode, consisting of a 6nm thick interface layer and a 14nm thick electrode layer.

[0120] Example 14

[0121] This embodiment is basically the same as embodiment 4, except that in this embodiment, the metal material in the cathode is changed from Ag to Al.

[0122] Comparative Example 1

[0123] This comparative example is basically the same as Example 1, except that the cathode is changed from a doped cathode to an Ag electrode, and correspondingly, the vapor deposition material in step S6 is changed to Ag. That is, the device structure is ITO / PEDOT:PSS / TFB / QD / ZnO / Ag.

[0124] Comparative Example 2

[0125] This comparative example is basically the same as Example 2, except that the cathode is changed from a doped cathode to an Ag electrode, and correspondingly, the vapor deposition material in step S6 is changed to Ag. That is, the device structure is ITO / PEDOT:PSS / TFB / QD / Bphen / Ag.

[0126] Comparative Example 3

[0127] This comparative example is basically the same as Example 14, except that the cathode is changed from a doped cathode to an Ag electrode, and correspondingly, the vapor deposition material is changed to Ag in step S6. That is, the device structure is ITO / PEDOT:PSS / TFB / QD / ZnO / Al.

[0128] Experimental Example

[0129] The QLED devices prepared in the above embodiments and comparative examples were subjected to performance tests, and the results are shown in Table 1. The testing methods are as follows:

[0130] (1) The test method for current efficiency CE is as follows: using the FPD optical characteristic measurement equipment, the efficiency test system is built by controlling the QE PRO spectrometer, Keithley 2400 and Keithley 6485 through LabVIEW, and the parameters such as voltage, current, brightness and emission spectrum are measured, and the current efficiency is calculated.

[0131] (2) Lifetime: The time required for the brightness of a device to decrease to a certain percentage of its maximum brightness under constant current or voltage driving. The time for the brightness to decrease to 95% of the maximum brightness is defined as T95, and this lifetime is the measured lifetime. To shorten the testing cycle, device lifetime testing is usually performed by accelerating device aging under high brightness, referencing OLED device testing, and the lifetime under high brightness is obtained by fitting the extended exponential decay brightness decay fitting formula. For example, the lifetime at 1000 nits is measured as T95. 1000nit The specific calculation formula is as follows:

[0132]

[0133] In the formula, T95 L For longer lifespan at low brightness, T95 H For the measured lifetime under high brightness, L H To accelerate the device to its maximum brightness, L L The value is 1000 nits, and A is the acceleration factor. For OLEDs, this value is usually 1.6 to 2. In this experiment, the lifetime of several groups of QLED devices under rated brightness was measured, and the value of A was found to be 1.7.

[0134] The life test system was used to test the life of the corresponding devices. The test conditions were: room temperature and air humidity of 30-60%.

[0135] Table 1

[0136]

[0137]

[0138] As can be seen from the table above:

[0139] Compared to Comparative Example 1, Examples 1 and Examples 3 to 13 all exhibit significantly higher CE and T95. 1000nit Compared to Comparative Example 2, Example 2 has higher CE and T95. 1000nit Compared to Comparative Example 3, Example 14 has higher CE and T95. 1000nit This indicates that in the light-emitting device provided in this application, by introducing thiadiazole compounds into the cathode, the reactivity of the metal electrode is reduced, thereby reducing the probability of the metal electrode reacting with the metal oxide in the electronic functional layer, which helps to improve the luminous efficiency of the light-emitting device and extend the device's lifespan.

[0140] Furthermore, comparing Examples 1 to 4, it can be seen that Examples 3 and 4 exhibit higher CE and T95 values ​​compared to Examples 1 and 2. 1000nitFurthermore, Example 4 demonstrates the most significant improvement, illustrating that designing the electron transport layer as a stacked structure of inorganic and organic layers, with an organic layer placed between the inorganic layer and the cathode, helps to improve electron mobility while preventing the metal material of the cathode from reacting with zinc oxide, thus effectively improving the device's lifetime and current efficiency. By placing an ultrathin organic electron injection layer between the electron transport layer and the cathode, electron injection can be increased, further enhancing electron migration and improving the device's lifetime and current efficiency.

[0141] The technical solutions provided by 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, characterized in that, It includes a stacked anode, a light-emitting layer, an electronic functional layer, and a cathode, wherein the cathode is made of a metallic material and a thiadiazole compound, wherein the thiadiazole compound has the structure shown in formula (I); Equation (Ⅰ): Where n is 1 or 2; Each time R appears, it is independently selected from one or more combinations of deuterium, nitro, amino, halogen, hydroxyl, carboxyl, sulfonic acid, aldehyde, mercapto, cyano, C1-C30 alkyl, C3-C30 cycloalkyl, C1-C30 alkoxy, C1-C30 alkylthio, C6-C30 aryl, C5-C30 heteroaryl, C6-C30 aryloxy, and C5-C30 heteroaryloxy.

2. The light-emitting device according to claim 1, characterized in that, Each time R appears, it is independently selected from one or more combinations of amino, halogen, mercapto, C1-C30 alkyl, C1-C30 alkoxy, C1-C30 alkylthio, and C6-C30 aryl.

3. The light-emitting device according to claim 2, characterized in that, The thiadiazole compounds include one or more of 2-amino-1,3,4-thiadiazole, 2,5-dimercapto-1,3,4-thiadiazole, 2-amino-5-(4-chlorophenyl)-1,3,4-thiadiazole, 2-amino-5-methylthio-1,3,4-thiadiazole, 2-amino-5-trifluoromethyl-1,3,4-thiadiazole, and 5-methyl-1,3,4-thiadiazole-2-thiol.

4. The light-emitting device according to claim 1, characterized in that, The cathode is a doped electrode, and the material of the doped electrode is a mixture of the metal material and the thiadiazole compound.

5. The light-emitting device according to claim 4, characterized in that, In the doped electrode, the mass ratio of the thiadiazole compound to the metal material is 1–10:100; optionally, the mass ratio of the thiadiazole compound to the metal material is 3–8:100; and / or, The thickness of the doped electrode is 20–120 nm.

6. The light-emitting device according to claim 1, characterized in that, The cathode is a composite cathode, which includes an electrode layer and an interface layer disposed between the electrode layer and the electronic functional layer. The electrode layer is made of the metal material, and the interface layer is made of the thiadiazole compound.

7. The light-emitting device according to claim 6, characterized in that, The thickness of the interface layer is 1–5 nm; and / or, The thickness of the electrode layer is 20–120 nm.

8. The light-emitting device according to claim 1, characterized in that, The thiadiazole compound is coordinated with the metal atoms of the metallic material; and / or The metallic material includes one or more of Ag, Al, Cu, Mo, Au, Pt, Si, Ca, Mg and Ba.

9. The light-emitting device according to claim 1, characterized in that, The electronic functional layer includes an electron transport layer, which comprises one or both of an organic layer and an inorganic layer. When the electron transport layer comprises the organic layer and the inorganic layer, the inorganic layer is disposed between the organic layer and the light-emitting layer. The material of the organic layer comprises an N-type organic compound, which includes 1,3,5-tris(N-phenylbenzimidazol-2-yl)benzene, 2,9-dimethyl-4,7-diphenyl-1,10-phenylene oxide, etc. -Phenanthroline, 4,7-diphenyl-1,10-phenanthroline, 1,3-bis[5-(4-tert-butylphenyl)-2-[1,3,4]oxadiazolyl]benzene, 1,3,5-tris(4-pyridin-3-ylphenyl)benzene, 1,3,5-tris(3-pyridin-3-ylphenyl)benzene, 1,3-bis[2-(2,2-bipyridin-6-yl)-1,3,4-oxadiazol-5-yl]benzene, 2,5-diphenyl-1,3,4-oxadiazole, The inorganic layer comprises one or more of 2,5-bis(1-naphthyl)-1,3,4-oxadiazole; the inorganic layer material comprises at least one of metal oxide, doped metal oxide, group IIA-VIA semiconductor material, group IIIA-VA semiconductor material and group IB-IIIA-VIA semiconductor material, wherein the metal oxide comprises one or more of ZnO, TiO2 and SnO2, the doped metal oxide comprises one or more of ZnO, TiO2 and SnO2, the doping element comprises one or more of Al, Mg, Li, In and Ga, the group IIA-VIA semiconductor material comprises at least one of ZnS, ZnSe and CdS, the group IIIA-VA semiconductor material comprises at least one of InP and GaP, and the group IB-IIIA-VIA semiconductor material comprises at least one of CuInS and CuGaS.

10. The light-emitting device according to claim 9, characterized in that, The thickness of the electron transport layer is 20–60 nm; optionally, when the electron transport layer includes the organic layer and the inorganic layer, the thickness ratio of the organic layer to the inorganic layer is 30–40:

1.

11. The light-emitting device according to claim 9, characterized in that, The electronic functional layer further includes an electron injection layer disposed between the electron transport layer and the cathode. The material of the electron injection layer includes one or more of organic compounds and fullerenes. Optionally, the material of the electron injection layer is one or more of lithium 8-hydroxyquinoline, lithium 2-methyl-8-hydroxyquinoline, and C60; and / or The thickness of the electron injection layer is 0.5–20 nm; optionally, the thickness of the electron injection layer is 0.5–2 nm.

12. The light-emitting device according to claim 1, characterized in that, The light-emitting device further includes a hole functional layer disposed between the light-emitting layer and the anode. The hole functional layer includes a hole transport layer and a hole injection layer. The hole injection layer is located between the hole transport layer and the anode. The material of the hole transport layer includes 4,4'-N,N'-dicarbazolyl-biphenyl, poly[(9,9'-dioctylfluorene-2,7-diyl)-co-(4,4'-(N-(4-sec-butylphenyl)diphenylamine))], N,N'-diphenyl-N,N'-bis(1-naphthyl)-1,1'-biphenyl-4,4”-diamine, and N,N'-diphenyl-N, N'-bis(3-methylphenyl)-(1,1'-biphenyl)-4,4'-diamine, 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-3-methylphenyl-N-phenylamino)triphenylamine, poly(p-)phenylenevinylene, poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene], poly[2-methoxy-5-(3',7'-dimethyloctyloxy)-1,4-phenylenevinylene] Vinyl, 4,4'-bis(p-carbazolyl)-1,1'-biphenyl compounds, N,N,N',N'-tetraarylbenzidine, PEDOT:PSS, poly(N-vinylcarbazole), polymethacrylate, poly(9,9-octylfluorene), N,N'-di(naphthyl-1-yl)-N,N'-diphenylbenzidine, spiron NPB, doped graphene, undoped graphene, doped or undoped metal oxides, wherein the metal oxides include one or more of NiO, MoO2, WO3, and CuO; the hole injection layer material includes poly(3,4-ethylenedioxy) Thiophene), poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid, 2,3,5,6-tetrafluoro-7,7',8,8'-tetracyanoquinone-dimethane, 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazabenzophenanthrene, copper carbonate polyester, transition metal oxides, and metal chalcogenides; wherein the transition metal oxides include one or more of NiO, MoO2, WO3, and CuO; and the metal chalcogenides include one or more of MoS2, MoSe2, WS3, WSe3, and CuS; and / or, The anode includes a doped metal oxide particle electrode, a metal-metal oxide composite electrode, a graphene electrode, a carbon nanotube electrode, or a metal electrode. The material of the doped metal oxide particle electrode is selected from one or more of indium-doped tin oxide, fluorine-doped tin oxide, antimony-doped tin oxide, aluminum-doped zinc oxide, gallium-doped zinc oxide, indium-doped zinc oxide, magnesium-doped zinc oxide, and aluminum-doped magnesium oxide. The metal-metal oxide composite electrode is selected from 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, and ZnS / Al / ZnS. The material of the metal electrode is selected from one or more of Ag, Al, Cu, Mo, Au, Pt, Si, Ca, Mg, and Ba; and / or, The material of the light-emitting layer includes organic light-emitting materials or quantum dot light-emitting materials. The organic light-emitting materials include at least one of the following: diaromatic anthracene derivatives, stilbene aromatic derivatives, pyrene derivatives or fluorene derivatives, blue-emitting TBPe fluorescent materials, green-emitting TTPA fluorescent materials, orange-emitting TBRb fluorescent materials, and red-emitting DBP fluorescent materials. The quantum dot light-emitting materials include at least one of single-structure quantum dots, core-shell structure quantum dots, and perovskite semiconductor materials. The shell of the core-shell structure quantum dots comprises one or more layers. The material of the single-structure quantum dots, the core material of the core-shell structure quantum dots, and the shell material of the core-shell structure quantum dots respectively include group II-VI compounds, group IV-VI compounds, and group IV-VI compounds. At least one of group II-VI compounds, group III-V compounds, and group I-III-VI compounds; said group II-VI compounds include CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe, CdSeS, CdSeTe, CdSTe, ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, CdZnS, CdZnSe, CdZnTe, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, HgZnTe, CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeS, CdHg At least one of SeTe, CdHgSTe, HgZnSeS, HgZnSeTe, and HgZnSTe; the IV-VI compounds include at least one of SnS, SnSe, SnTe, PbS, PbSe, PbTe, SnSeS, SnSeTe, SnSTe, PbSeS, PbSeTe, PbSTe, SnPbS, SnPbSe, SnPbTe, SnPbSSe, SnPbSeTe, and SnPbSTe; the III-V compounds include at least one of GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, InSb, GaNP, and G. At least one of aNAs, GaNSb, GaPAs, GaPSb, AlNP, AlNAs, AlNSb, AlPAs, AlPSb, InNP, InNAs, InNSb, InPAs, InPSb, GaAlNP, GaAlNAs, GaAlNSb, GaAlPAs, GaAlPSb, GaInNP, GaInNAs, GaInNSb, GaInPAs, GaInPSb, InAlNP, InAlNAs, InAlNSb, InAlPAs, and InAlPSb; the group I-III-VI compounds include at least one of CuInS2, CuInSe2, and AgInS2;The perovskite semiconductor material is selected from doped or undoped inorganic perovskite semiconductors or organic-inorganic hybrid perovskite semiconductors; the general structural formula of the inorganic perovskite semiconductor is AMX3, where A is Cs; + Ion, M is a divalent metal cation selected from Pb 2+ Sn 2+ Cu 2+ Ni 2+ Cd 2+ Cr 2+ Mn 2+ Co 2+ Fe 2+ 、Ge 2+ Yb 2+ Eu 2+ At least one of them, where X is a halide anion selected from Cl. - ,Br - I - At least one of the following; the general structural formula of the organic-inorganic hybrid perovskite semiconductor is BMX3, wherein B is an organic amine cation selected from CH3(CH2). n-2 NH3 + Or [NH3(CH2)] n NH3] 2+ Where n≥2, M is a divalent metal cation selected from Pb 2+ Sn 2+ Cu 2+ Ni 2+ Cd 2+ Cr 2+ Mn 2+ Co 2+ Fe 2+ 、Ge 2+ Yb 2+ Eu 2+ At least one of them, where X is a halide anion selected from Cl. - ,Br - I - At least one of them.

13. A display device, characterized in that, Includes the light-emitting device according to any one of claims 1 to 12.

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