US-12622132-B2 - Light-emitting device, light-emitting apparatus, electronic device, and lighting device

US12622132B2US 12622132 B2US12622132 B2US 12622132B2US-12622132-B2

Abstract

The reliability of a light-emitting device is improved. Provided is a light-emitting device including a light-emitting layer between a first electrode and a second electrode. The light-emitting layer contains a light-emitting substance and a first organic compound. A difference between a sum of energy of the first organic compound in a ground state and energy of an oxygen molecule in a ground state and energy of a transition state formed by the first organic compound and the oxygen molecule is greater than or equal to 1.84 eV. A difference between the energy of the transition state formed by the first organic compound and the oxygen molecule and energy of an oxygen adduct of the first organic compound in a ground state is less than or equal to 0.87 eV.

Inventors

Akira Nagasaka
Kunihiko Suzuki
Ryo NARUKAWA

Assignees

SEMICONDUCTOR ENERGY LABORATORY CO., LTD.

Dates

Publication Date: 20260505
Application Date: 20230803
Priority Date: 20220810

Claims (12)

1 . A light-emitting device comprising: a first electrode; a second electrode; and a light-emitting layer between the first electrode and the second electrode, wherein the light-emitting layer comprises a light-emitting substance and a first organic compound, wherein a difference between a sum of energy of the first organic compound in a ground state and energy of an oxygen molecule in a ground state and energy of a transition state formed by the first organic compound and the oxygen molecule is greater than or equal to 1.84 eV, and wherein a difference between the energy of the transition state formed by the first organic compound and the oxygen molecule and energy of an oxygen adduct of the first organic compound in a ground state is less than or equal to 0.87 eV.
2 . The light-emitting device according to claim 1 , wherein the energy of the oxygen adduct of the first organic compound in a ground state is higher than the sum of the energy of the first organic compound in a ground state and the energy of the oxygen molecule in a ground state, and wherein a difference between the energy of the oxygen adduct of the first organic compound in a ground state and the sum of the energy of the first organic compound in a ground state and the energy of the oxygen molecule in a ground state is greater than or equal to 0.97 eV.
3 . The light-emitting device according to claim 1 , wherein the first organic compound comprises a first partial structure and a second partial structure different from the first partial structure, wherein highest occupied molecular orbital distribution of the first organic compound is located on the first partial structure, and wherein the oxygen adduct is formed when an oxygen molecule is added to the second partial structure.
4 . A light-emitting apparatus comprising: the light-emitting device according to claim 1 ; and a transistor or a substrate.
5 . An electronic device comprising: the light-emitting apparatus according to claim 4 ; and a sensor unit, an input unit, or a communication unit.
6 . A lighting device comprising: the light-emitting apparatus according to claim 4 ; and a housing.
7 . A light-emitting device comprising: a first electrode; a second electrode; and a light-emitting layer between the first electrode and the second electrode, wherein the light-emitting layer comprises a light-emitting substance and a first organic compound, wherein the first organic compound is represented by any one of General Formula (G1-1), General Formula (G1-2), and General Formula (G1-3), wherein, in the Formula (G1-1), General Formula (G1-2), and General Formula (G1-3): Q 1 represents oxygen or sulfur; each of R 1 to R 8 independently represents any one of hydrogen, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted aryl group having 6 to 18 carbon atoms, substituted or unsubstituted monocyclic saturated hydrocarbon having 5 to 7 carbon atoms, and substituted or unsubstituted polycyclic saturated hydrocarbon having 7 to 10 carbon atoms; n represents an integer of 0 to 4; Ht uni represents a hole-transport skeleton; each of A1, A2, and A3 is represented by any one of General Formulae (Ax-1) to (Ax-5); Q 2 represents oxygen or sulfur; each of R 11 to R 14 independently represents any one of hydrogen, an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted aryl group having 6 to 18 carbon atoms, substituted or unsubstituted monocyclic saturated hydrocarbon having 5 to 7 carbon atoms, and substituted or unsubstituted polycyclic saturated hydrocarbon having 7 to 10 carbon atoms; each of R 15 to R 19 represents 1 to 4 substituents and independently represents any one of hydrogen, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted aryl group having 6 to 18 carbon atoms, substituted or unsubstituted monocyclic saturated hydrocarbon having 5 to 7 carbon atoms, and substituted or unsubstituted polycyclic saturated hydrocarbon having 7 to 10 carbon atoms; and * represents a bonding portion with any one of benzofuropyrimidine rings and benzothienopyrimidine rings in the General Formula (G1-1), General Formula (G1-2), and General Formula (G1-3), wherein a difference between a sum of energy of the first organic compound in a ground state and energy of an oxygen molecule in a ground state and energy of a transition state formed by the first organic compound and the oxygen molecule is greater than or equal to 1.84 eV, and wherein a difference between the energy of the transition state formed by the first organic compound and the oxygen molecule and energy of an oxygen adduct of the first organic compound in a ground state is less than or equal to 0.87 eV.
8 . The light-emitting device according to claim 7 , wherein the energy of the oxygen adduct of the first organic compound in a ground state is higher than the sum of the energy of the first organic compound in a ground state and the energy of the oxygen molecule in a ground state, and wherein a difference between the energy of the oxygen adduct of the first organic compound in a ground state and the sum of the energy of the first organic compound in a ground state and the energy of the oxygen molecule in a ground state is greater than or equal to 0.97 eV.
9 . The light-emitting device according to claim 7 , wherein the first organic compound comprises a first partial structure and a second partial structure different from the first partial structure, wherein highest occupied molecular orbital distribution of the first organic compound is located on the first partial structure, and wherein the oxygen adduct is formed when an oxygen molecule is added to the second partial structure.
10 . A light-emitting apparatus comprising: the light-emitting device according to claim 7 ; and a transistor or a substrate.
11 . An electronic device comprising: the light-emitting apparatus according to claim 10 ; and a sensor unit, an input unit, or a communication unit.
12 . A lighting device comprising: the light-emitting apparatus according to claim 10 ; and a housing.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention One embodiment of the present invention relates to a light-emitting device, a light-emitting apparatus, an electronic device, and a lighting device. Note that one embodiment of the present invention is not limited to the above technical field. The technical field of one embodiment of the invention disclosed in this specification and the like relates to an object, a method, or a manufacturing method. One embodiment of the present invention relates to a process, a machine, manufacture, or a composition of matter. Specifically, examples of the technical field of one embodiment of the present invention disclosed in this specification include a semiconductor device, a display apparatus, a liquid crystal display apparatus, a light-emitting apparatus, a lighting device, a power storage device, a memory device, an imaging device, a driving method thereof, and a manufacturing method thereof. 2. Description of the Related Art A light-emitting device (also referred to as an organic EL element) including an organic compound that is a light-emitting substance between a pair of electrodes has characteristics such as being thin and light in weight, high-speed response, and low voltage driving. Thus, displays including such light-emitting devices have been developed. When a voltage is applied to this light-emitting device, electrons and holes injected from the electrodes recombine to put the light-emitting substance into an excited state. Light is emitted when the light-emitting substance returns to a ground state from the excited state. The excited state can be a singlet excited state (S*) and a triplet excited state (T*). Light emission from a singlet excited state is referred to as fluorescence, and light emission from a triplet excited state is referred to as phosphorescence. The statistical generation ratio in the light-emitting device is considered to be S*:T*=1:3. As the above light-emitting substance, a compound capable of converting singlet excitation energy into light emission is called a fluorescent compound (fluorescent material), and a compound capable of converting triplet excitation energy into light emission is called a phosphorescent compound (phosphorescent material). Accordingly, on the basis of the above generation ratio, the internal quantum efficiency (the ratio of the number of generated photons to the number of injected carriers) of a light-emitting device containing a fluorescent material is thought to have a theoretical limit of 25%, while the internal quantum efficiency of a light-emitting device containing a phosphorescent material is thought to have a theoretical limit of 75%. Since light-emitting layers of such light-emitting devices can be successively formed two-dimensionally, planar light emission can be achieved. This feature is difficult to realize with point light sources typified by incandescent lamps or LEDs or linear light sources typified by fluorescent lamps; thus, such light-emitting devices also have great potential as planar light sources, which can be applied to lighting devices and the like. To improve device characteristics of the light-emitting devices, development of a substance, improvement of a device structure, and the like have been carried out. For example, Patent Document 1 discloses a light-emitting device or the like in which a novel anthracene derivative is used as a host material to obtain a light-emitting element with high emission efficiency. REFERENCE [Patent Document 1] Japanese Published Patent Application No. 2014-076999 SUMMARY OF THE INVENTION As described above, for the improvement of the characteristics of light-emitting devices, organic compounds with characteristics suitable for light-emitting elements have been developed. In blue fluorescent light-emitting devices, for example, high emission efficiency can be obtained when an anthracene derivative is used as a host material; thus, many materials using an anthracene derivative have been developed. However, an anthracene skeleton easily results in formation of an oxygen adduct by reacting with oxygen in an oxygen-existing environment. When oxygen is added to an anthracene skeleton, the characteristics of a light-emitting device using an anthracene derivative are decreased. Hence, one embodiment of the present invention uses a host material from which an oxygen adduct is less likely to be formed to provide a light-emitting device with high emission efficiency. With the use of a novel organic compound, which is one embodiment of the present invention, a light-emitting device with high emission efficiency is provided. Furthermore, a highly reliable light-emitting device is provided. Note that the description of these objects does not preclude the existence of other objects. One embodiment of the present invention does not need to achieve all of these objects. Other objects can be derived from the description of the specification, the drawings, and the cl