# US 2014/0191220 A1 · Light-Emitting Element, Light-Emitting Device, Electronic Device, 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 2014/0191220 A1 - Document ID: US20140191220A1 - Status: Published application - Kind: A1 - Application number: 14/150,388 - Filed: 2014-01-08 - Published: 2014-07-10 - Earliest claimed: 2013-01-10 - Assignees: Semiconductor Energy Laboratory Co., Ltd. - Applicants: Semiconductor Energy Laboratory Co., Ltd. - Inventors: Takeyoshi Watabe; Satoshi Seo - Web page: https://patentgrep.com/patent/US20140191220A1 ## CPC - H10K 85/6576: {comprising only sulfur in the heteroaromatic polycondensed ring system, e.g. benzothiophene} - H10K 50/11: characterised by the electroluminescent [EL] layers - H10K 50/121: {for assisting energy transfer, e.g. sensitization} - H10K 85/342: {comprising iridium} - 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 85/6572: {comprising only nitrogen in the heteroaromatic polycondensed ring system, e.g. phenanthroline or carbazole} - H10K 59/12: Active-matrix OLED [AMOLED] displays - H10K 85/615: {Polycyclic condensed aromatic hydrocarbons, e.g. anthracene} - H10K 85/631: {Amine compounds having at least two aryl rest on at least one amine-nitrogen atom, e.g. triphenylamine} - H10K 2101/10: Triplet emission - H10K 2101/20: Delayed fluorescence emission - H10K 2101/90: {Multiple hosts in the emissive layer} - H10K 2102/361: {Temperature} - H10K: ORGANIC ELECTRIC SOLID-STATE DEVICES ## Abstract A light-emitting element of the present invention can have sufficiently high emission efficiency with a structure including a host material being able to remain chemically stable even if a phosphorescent compound having higher emission energy is used as a guest material. The relation between the relative emission intensity and the emission time of light emission obtained from the host material and the guest material contained in a light-emitting layer is represented by a multicomponent decay curve. The relative emission intensity of the slowest component of the multicomponent decay curve becomes 1/100 for a short time within a range where the slowest component is not interfered with by quenching of the host material (the emission time of the slowest component is preferably less than or equal to 15 μsec); thus, sufficiently high emission efficiency can be obtained. ## Claims ### Claim 1 A light-emitting device comprising: a light-emitting layer, wherein emission time-dependence of emission intensity of the light-emitting device is represented by a multicomponent decay curve, and wherein an emission time of a slowest component of the multicomponent decay curve is less than or equal to 15 μsec where the emission time is a time required for the emission intensity to become 1/100. ### Claim 2 (depends on 1) The light-emitting device according to claim 1, wherein the light-emitting device is configured to emit blue light. ### Claim 3 (depends on 1) An electronic device comprising the light-emitting device according to claim 1. ### Claim 4 (depends on 1) A lighting device comprising the light-emitting device according to claim 1. ### Claim 5 A light-emitting device comprising: a light-emitting layer comprising at least a first organic compound and a second organic compound, wherein the first organic compound and the second organic compound are selected so that emission time-dependence of emission intensity of the light-emitting device is represented by a multicomponent decay curve, and wherein an emission time of a slowest component of the multicomponent decay curve is less than or equal to 15 μsec where the emission time is a time required for the emission intensity to become 1/100. ### Claim 6 (depends on 5) The light-emitting device according to claim 5, wherein the multicomponent decay curve represents at least two components derived from the first organic compound and/or the second organic compound at the time when the emission intensity becomes 1/100. ### Claim 7 (depends on 5) The light-emitting device according to claim 5, wherein the light-emitting device is configured to emit blue light. ### Claim 8 (depends on 5) An electronic device comprising the light-emitting device according to claim 5. ### Claim 9 (depends on 5) A lighting device comprising the light-emitting device according to claim 5. ### Claim 10 A light-emitting device comprising: a light-emitting layer comprising a guest material and a host material, wherein a T1 level of the guest material is equal to or lower than a T1 level of the host material, wherein the guest material and the host material are selected so that emission time-dependence of emission intensity of the light-emitting device is represented by a multicomponent decay curve, and wherein an emission time of a slowest component of the multicomponent decay curve is less than or equal to 15 μsec where the emission time is a time required for the emission intensity to become 1/100. ### Claim 11 (depends on 10) The light-emitting device according to claim 10, wherein a difference between the T1 level of the guest material and the T1 level of the host material is greater than or equal to 0 eV and less than or equal to 0.2 eV. ### Claim 12 (depends on 10) The light-emitting device according to claim 10, wherein the guest material is a phosphorescence compound. ### Claim 13 (depends on 10) The light-emitting device according to claim 10, wherein the multicomponent decay curve represents at least two components derived from the guest material at the time when the emission intensity becomes 1/100. ### Claim 14 (depends on 10) The light-emitting device according to claim 10, wherein the light-emitting device is configured to emit blue light. ### Claim 15 (depends on 10) An electronic device comprising the light-emitting device according to claim 10. ### Claim 16 (depends on 10) A lighting device comprising the light-emitting device according to claim 10.