# US 12,114,521 B2 · Light-emitting element and display device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,114,521 B2 - Document ID: US12114521B2 - Status: Granted - Kind: B2 - Application number: 17/434,348 - Filed: 2019-03-04 - Published: 2022-05-19 - Granted: 2024-10-08 - Earliest claimed: 2019-03-04 - Assignees: Sharp Kabushiki Kaisha - Applicants: Sharp Kabushiki Kaisha - Inventors: Takayuki Naka; Yoshihiro Ueta; Noboru Iwata - Web page: https://patentgrep.com/patent/US12114521B2 ## CPC - H10K 50/18: Carrier blocking layers - G09F 9/30: in which the desired character or characters are formed by combining individual elements (panels comprising a number of electrodes in a single cell controlling light arriving from an independent light source, e.g. electro-optical or magneto-optical cell, G02F1/00) - H05B 33/14: characterised by the chemical or physical composition or the arrangement of the electroluminescent material {, or by the simultaneous addition of the electroluminescent material in or onto the light source} - H05B 33/22: characterised by the chemical or physical composition or the arrangement of auxiliary dielectric or reflective layers - H10K 50/11: characterised by the electroluminescent [EL] layers - H10K 50/17: Carrier injection layers - H10K 59/35: comprising red-green-blue [RGB] subpixels - H10K 85/115: {Polyfluorene; Derivatives thereof} - H10K 85/141: {comprising aliphatic or olefinic chains, e.g. poly N-vinylcarbazol, PVC or PTFE} - H10K 85/146: {poly N-vinylcarbazol; Derivatives thereof} - H10K 50/115: comprising active inorganic nanostructures, e.g. luminescent quantum dots - H10K 50/16: Electron transporting layers - H10K 59/12: Active-matrix OLED [AMOLED] displays - H10K 2101/40: Interrelation of parameters between multiple constituent active layers or sublayers, e.g. HOMO values in adjacent layers - H10K 2102/00: Constructional details relating to the organic devices covered by this subclass - H10K 2102/331: {Nanoparticles used in non-emissive layers, e.g. in packaging layer} - H10K 2102/351: {Thickness} - H10K: ORGANIC ELECTRIC SOLID-STATE DEVICES - G09F: DISPLAYING; ADVERTISING; SIGNS; LABELS OR NAME-PLATES; SEALS - H05B: ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL ## Abstract A light-emitting element is provided with an anode, a light-emitting layer including quantum dots, and a cathode. The light-emitting element includes: an electron transport layer provided between the cathode and the light-emitting layer; and a hole tunneling insulating layer provided between the anode and the light-emitting layer and in contact with the anode and the light-emitting layer. ## Claims ### Claim 1 A light-emitting element provided with an anode, a light-emitting layer including quantum dots, and a cathode, the light-emitting element comprising: an electron transport layer provided between the cathode and the light-emitting layer; and a hole tunneling insulating layer provided between the anode and the light-emitting layer and in contact with the anode and the light-emitting layer, wherein the hole tunneling insulating layer includes a plurality of layers composed of different materials. ### Claim 2 (depends on 1) The light-emitting element according to claim 1, wherein a thickness of the hole tunneling insulating layer is 0.1 nm or greater and 2.2 nm or less. ### Claim 3 (depends on 1) The light-emitting element according to claim 1, wherein an electron affinity value of the hole tunneling insulating layer is smaller than an electron affinity value of the light-emitting layer by 0.5 eV or greater, and an ionization potential value of the hole tunneling insulating layer is greater than a value obtained by subtracting 0.5 eV from an ionization potential value of the light-emitting layer. ### Claim 4 (depends on 1) The light-emitting element according to claim 1, wherein the hole tunneling insulating layer is composed of an inorganic material. ### Claim 5 (depends on 4) The light-emitting element according to claim 4, wherein the inorganic material includes any one of aluminum oxide, silicon oxide, silicon oxynitride, and silicon nitride. ### Claim 6 (depends on 1) The light-emitting element according to claim 1, wherein the hole tunneling insulating layer is composed of an organic material. ### Claim 7 (depends on 6) The light-emitting element according to claim 6, wherein the organic material includes any one of polymethyl methacrylate (PMMA), polyvinyl carbazole (PVK), and poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(4,4′-(N-(4-sec-butylphenyl))diphenylamine)] (TFB). ### Claim 8 (depends on 1) The light-emitting element according to claim 1, wherein a band gap of the hole tunneling insulating layer is 3 eV or greater. ### Claim 9 (depends on 1) The light-emitting element according to claim 1, wherein the electron transport layer includes zinc oxide or titanium oxide. ### Claim 10 (depends on 1) The light-emitting element according to claim 1, wherein the electron transport layer includes magnesium zinc oxide. ### Claim 11 (depends on 9) The light-emitting element according to claim 9, wherein the electron transport layer is formed of nanoparticles. ### Claim 12 (depends on 1) A display device comprising the light-emitting element according to claim 1. ### Claim 13 (depends on 12) The display device according to claim 12, further comprising: a plurality of light-emitting elements, including the light-emitting element, wherein the plurality of light-emitting elements includes a first light-emitting element, a second light-emitting element, and a third light-emitting element, an emission peak wavelength of the first light-emitting element is longer than an emission peak wavelength of the second light-emitting element, and the emission peak wavelength of the second light-emitting element is longer than an emission peak wavelength of the third light-emitting element. ### Claim 14 (depends on 13) The display device according to claim 13, wherein the first light-emitting element includes a first light-emitting layer as the light-emitting layer and a first hole tunneling insulating layer as the hole tunneling insulating layer, the second light-emitting element includes a second light-emitting layer as the light-emitting layer and a second hole tunneling insulating layer as the hole tunneling insulating layer, the third light-emitting element includes a third light-emitting layer as the light-emitting layer and a third hole tunneling insulating layer as the hole tunneling insulating layer, the first hole tunneling insulating layer, the second hole tunneling insulating layer, and the third hole tunneling insulating layer are formed of an identical material, electron affinity values of the first hole tunneling insulating layer, the second hole tunneling insulating layer, and the third hole tunneling insulating layer are smaller than a smallest value of an electron affinity value of the first light-emitting layer, an electron affinity value of the second light-emitting layer, and an electron affinity value of the third light-emitting layer by 0.5 eV or greater, and ionization potential values of the first hole tunneling insulating layer, the second hole tunneling insulating layer, and the third hole tunneling insulating layer are larger than a value obtained by subtracting 0.5 eV from a greatest value of an ionization potential value of the first light-emitting layer, an ionization potential value of the second light-emitting layer, and an ionization potential value of the third light-emitting layer. ### Claim 15 (depends on 13) The display device according to claim 13, wherein the first light-emitting element includes a first light-emitting layer as the light-emitting layer and a first hole tunneling insulating layer as the hole tunneling insulating layer, the second light-emitting element includes a second light-emitting layer as the light-emitting layer and a second hole tunneling insulating layer as the hole tunneling insulating layer, the third light-emitting element includes a third light-emitting layer as the light-emitting layer and a third hole tunneling insulating layer as the hole tunneling insulating layer, the first hole tunneling insulating layer, the second hole tunneling insulating layer, and the third hole tunneling insulating layer are formed of different materials, an electron affinity value of the first hole tunneling insulating layer is smaller than an electron affinity value of the first light-emitting layer by 0.5 eV or greater, an electron affinity value of the second hole tunneling insulating layer is smaller than an electron affinity value of the second light-emitting layer by 0.5 eV or greater, an electron affinity value of the third hole tunneling insulating layer is smaller than an electron affinity value of the third light-emitting layer by 0.5 eV or greater, an ionization potential value of the first hole tunneling insulating layer is greater than a value obtained by subtracting 0.5 eV from an ionization potential value of the first light-emitting layer, an ionization potential value of the second hole tunneling insulating layer is greater than a value obtained by subtracting 0.5 eV from an ionization potential value of the second light-emitting layer, and an ionization potential value of the third hole tunneling insulating layer is greater than a value obtained by subtracting 0.5 eV from an ionization potential value of the third light-emitting layer. ### Claim 16 (depends on 15) The display device according to claim 15, wherein the electron affinity value of the third hole tunneling insulating layer is greater than the electron affinity value of the second hole tunneling insulating layer, and the electron affinity value of the second hole tunneling insulating layer is greater than the electron affinity value of the first hole tunneling insulating layer. ### Claim 17 (depends on 15) The display device according to claim 15, wherein the first hole tunneling insulating layer includes any one of silicon oxynitride, silicon oxide, and aluminum oxide. ### Claim 18 (depends on 15) The display device according to claim 15, wherein the second hole tunneling insulating layer includes any one of aluminum oxide and polyvinyl carbazole (PVK). ### Claim 19 (depends on 15) The display device according to claim 15, wherein the third hole tunneling insulating layer includes any one of silicon nitride, polyvinyl carbazole (PVK), and polymethyl methacrylate (PMMA). ### Claim 20 (depends on 14) The display device according to claim 14, wherein the identical material includes any one of silicon oxide, aluminum oxide, silicon nitride, polyvinyl carbazole (PVK), and polymethyl methacrylate (PMMA). ### Claim 21 (depends on 14) The display device according to claim 14, wherein a film thickness of the first hole tunneling insulating layer is greater than a film thickness of the second hole tunneling insulating layer, and the film thickness of the second hole tunneling insulating layer is greater than a film thickness of the third hole tunneling insulating layer. ### Claim 22 (depends on 14) The display device according to claim 14, wherein the first light-emitting element further includes a first electron transport layer as the electron transport layer, the second light-emitting element further includes a second electron transport layer as the electron transport layer, the third light-emitting element further includes a third electron transport layer as the electron transport layer, an electron affinity value of the first electron transport layer is greater than the electron affinity value of the first light-emitting layer by of 0.5 eV or less, an electron affinity value of the second electron transport layer is greater than the electron affinity value of the second light-emitting layer by 0.5 eV or less, and an electron affinity value of the third electron transport layer is greater than the electron affinity value of the third light-emitting layer by 0.5 eV or less. ### Claim 23 (depends on 22) The display device according to claim 22, wherein the electron affinity value of the first electron transport layer is greater than the electron affinity value of the second electron transport layer, and the electron affinity value of the second electron transport layer is greater than the electron affinity value of the third electron transport layer. ### Claim 24 (depends on 13) The display device according to claim 13, wherein the first light-emitting element is a light-emitting element configured to emit red light, the second light-emitting element is a light-emitting element configured to emit green light, and the third light-emitting element is a light-emitting element configured to emit blue light. ### Claim 25 A light-emitting element provided with an anode, a light-emitting layer including quantum dots, and a cathode, the light-emitting element comprising: an electron transport layer provided between the cathode and the light-emitting layer and in contact with the cathode and the light-emitting layer; and a hole tunneling insulating layer provided between the anode and the light-emitting layer and in contact with the anode and the light-emitting layer, wherein the electron transport layer includes magnesium zinc oxide, and the electron transport layer is formed of nanoparticles.