# US 10,374,186 B2 · Light-emitting element, display module, lighting module, light-emitting device, display device, electronic appliance, and lighting device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,374,186 B2 - Document ID: US10374186B2 - Status: Granted - Kind: B2 - Application number: 15/983,223 - Filed: 2018-05-18 - Published: 2018-09-20 - Granted: 2019-08-06 - Earliest claimed: 2013-12-02 - Assignees: Semiconductor Energy Laboratory Co., Ltd. - Applicants: Semiconductor Energy Laboratory Co., Ltd. - Inventors: Nobuharu Ohsawa; Yusuke Nonaka; Takahiro Ishisone; Satoshi Seo; Takuya Kawata - Web page: https://patentgrep.com/patent/US10374186B2 ## CPC - H10K 50/131: {with spacer layers between the electroluminescent layers} - H10K 50/11: characterised by the electroluminescent [EL] layers - H10K 50/121: {for assisting energy transfer, e.g. sensitization} - H10K 50/15: Hole transporting layers - H10K 50/16: Electron transporting layers - H10K 59/32: Stacked devices having two or more layers, each emitting at different wavelengths - H10K 85/342: {comprising iridium} - H10K 85/611: {Charge transfer complexes} - H10K 85/615: {Polycyclic condensed aromatic hydrocarbons, e.g. anthracene} - H10K 85/622: {containing four rings, e.g. pyrene} - H10K 85/626: {containing more than one polycyclic condensed aromatic rings, e.g. bis-anthracene} - H10K 85/633: {comprising polycyclic condensed aromatic hydrocarbons as substituents on the nitrogen atom} - H10K 85/636: {comprising heteroaromatic hydrocarbons as substituents on the nitrogen atom} - H10K 85/654: {comprising only nitrogen as heteroatom (H10K85/652 takes precedence)} - H10K 85/6572: {comprising only nitrogen in the heteroaromatic polycondensed ring system, e.g. phenanthroline or carbazole} - H10K 85/6576: {comprising only sulfur in the heteroaromatic polycondensed ring system, e.g. benzothiophene} - H10K 2101/10: Triplet emission - H10K 2101/20: Delayed fluorescence emission - H10K 2101/27: {Combination of fluorescent and phosphorescent emission} - H10K 2101/90: {Multiple hosts in the emissive layer} - H10K 2102/351: {Thickness} - Y02B 20/00: Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps - H10K: ORGANIC ELECTRIC SOLID-STATE DEVICES - Y02B: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS ## Abstract An object of one embodiment of the present invention is to provide a multicolor light-emitting element that utilizes fluorescence and phosphorescence and is advantageous for practical application. The light-emitting element has a stacked-layer structure of a first light-emitting layer containing a host material and a fluorescent substance, a separation layer containing a substance having a hole-transport property and a substance having an electron-transport property, and a second light-emitting layer containing two kinds of organic compounds that form an exciplex and a substance that can convert triplet excitation energy into luminescence. Note that a light-emitting element in which light emitted from the first light-emitting layer has an emission spectrum peak on the shorter wavelength side than an emission spectrum peak of the second light-emitting layer is more effective. ## Claims ### Claim 1 A light-emitting device comprising: an anode, a plurality of light-emitting layers, a first layer and a cathode, wherein the plurality of light-emitting layers comprises: a first light-emitting layer over the anode, the first light-emitting layer comprising a fluorescent substance and a host material; a second light-emitting layer over the first light-emitting layer; and a third light-emitting layer over and in contact with the second light-emitting layer; and wherein the first layer is positioned between the first light-emitting layer and the second light-emitting layer, wherein the cathode is positioned over the third light-emitting layer, wherein one of the second light-emitting layer and the third light-emitting layer comprises: a first light-emitting substance which is configured to convert triplet excitation energy into light emission; a first organic compound; and a second organic compound, wherein the first organic compound and the second organic compound are configured to form an exciplex, and wherein a difference between an energy value of a peak wavelength of an emission spectrum of the exciplex and an energy value of a peak wavelength of a lowest-energy absorption band of the first light-emitting substance is 0.2 eV or less. ### Claim 2 (depends on 1) The light-emitting device according to claim 1, wherein the second light-emitting layer comprises a second light-emitting substance which is configured to convert triplet excitation energy into light emission. ### Claim 3 (depends on 1) The light-emitting device according to claim 1, wherein the first light-emitting substance is a phosphorescent material. ### Claim 4 (depends on 1) The light-emitting device according to claim 1, wherein the second light-emitting layer comprises a second light-emitting substance which is configured to convert triplet excitation energy into light emission, and wherein each of the first light-emitting substance and the second light-emitting substance is a phosphorescent material. ### Claim 5 (depends on 1) The light-emitting device according to claim 1, wherein a peak wavelength of a spectrum emitted from the first light-emitting layer is shorter than a peak wavelength of a spectrum emitted from the second light-emitting layer, and wherein the peak wavelength of the spectrum emitted from the first light-emitting layer is shorter than a peak wavelength of a spectrum emitted from the third light-emitting layer. ### Claim 6 (depends on 1) The light-emitting device according to claim 1, wherein a peak wavelength of a spectrum emitted from the third light-emitting layer is shorter than a peak wavelength of a spectrum emitted from the second light-emitting layer. ### Claim 7 (depends on 1) The light-emitting device according to claim 1, wherein a triplet excited level of the host material is lower than a triplet excited level of the fluorescent substance. ### Claim 8 (depends on 1) The light-emitting device according to claim 1, wherein the host material has an anthracene skeleton. ### Claim 9 (depends on 1) The light-emitting device according to claim 1, wherein the fluorescent substance is a pyrenediamine compound. ### Claim 10 A light-emitting device comprising: a first light-emitting element, a second light-emitting element, a third light-emitting element and a fourth light-emitting element, each comprising an anode, a plurality of light-emitting layers, a first layer and a cathode, wherein the plurality of light-emitting layers each comprises: a first light-emitting layer over the anode and between the anode and the first layer, the first light-emitting layer each comprising a fluorescent substance and a host material; a second light-emitting layer over the first layer; and a third light-emitting layer over and in contact with the second light-emitting layer and between the second light-emitting layer and the cathode, wherein one of the second light-emitting layer and the third light-emitting layer each comprises: a first light-emitting substance which is configured to convert triplet excitation energy into light emission; a first organic compound; and a second organic compound, wherein the first organic compound and the second organic compound are configured to form an exciplex, and wherein a difference between an energy value of a peak wavelength of an emission spectrum of the exciplex and an energy value of a peak wavelength of a lowest-energy absorption band of the first light-emitting substance is 0.2 eV or less, wherein the first light-emitting element and a red color filter overlap each other, wherein the second light-emitting element and a green color filter overlap each other, wherein the third light-emitting element and a blue color filter overlap each other, and wherein the fourth light-emitting element has a region which overlap none of the red color filter, the green color filter or the blue color filter. ### Claim 11 (depends on 10) The light-emitting device according to claim 10, wherein the second light-emitting layer comprises a second light-emitting substance which is configured to convert triplet excitation energy into light emission. ### Claim 12 (depends on 10) The light-emitting device according to claim 10, wherein the first light-emitting substance is a phosphorescent material. ### Claim 13 (depends on 10) The light-emitting device according to claim 10, wherein the second light-emitting layer comprises a second light-emitting substance which is configured to convert triplet excitation energy into light emission, and wherein each of the first light-emitting substance and the second light-emitting substance is a phosphorescent material. ### Claim 14 (depends on 10) The light-emitting device according to claim 10, wherein a peak wavelength of a spectrum emitted from the first light-emitting layer is shorter than a peak wavelength of a spectrum emitted from the second light-emitting layer, and wherein the peak wavelength of the spectrum emitted from the first light-emitting layer is shorter than a peak wavelength of a spectrum emitted from the third light-emitting layer. ### Claim 15 (depends on 10) The light-emitting device according to claim 10, wherein a peak wavelength of a spectrum emitted from the third light-emitting layer is shorter than a peak wavelength of a spectrum emitted from the second light-emitting layer. ### Claim 16 (depends on 10) The light-emitting device according to claim 10, wherein a triplet excited level of the host material is lower than a triplet excited level of the fluorescent substance. ### Claim 17 (depends on 10) The light-emitting device according to claim 10, wherein the host material has an anthracene skeleton. ### Claim 18 (depends on 10) The light-emitting device according to claim 10, wherein the fluorescent substance is a pyrenediamine compound.