# US 12,225,748 B2 · Light-emitting element, display device, electronic device, and lighting device

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- Number: US 12,225,748 B2
- Document ID: US12225748B2
- Status: Granted
- Kind: B2
- Application number: 18/788,835
- Filed: 2024-07-30
- Published: 2024-11-28
- Granted: 2025-02-11
- Earliest claimed: 2015-07-23
- Assignees: Semiconductor Energy Laboratory Co., Ltd.
- Applicants: Semiconductor Energy Laboratory Co., Ltd.
- Inventors: Satoshi Seo; Tatsuyoshi Takahashi; Takeyoshi Watabe; Satomi Mitsumori
- Web page: https://patentgrep.com/patent/US12225748B2

## CPC

- C07F 15/0033: {Iridium compounds}
- C09K 11/06: containing organic luminescent materials
- 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 59/38: comprising colour filters or colour changing media [CCM]
- H10K 59/40: OLEDs integrated with touch screens
- C09K 2211/1007: Non-condensed systems
- C09K 2211/1011: Condensed systems
- C09K 2211/1059: containing three nitrogen atoms as heteroatoms
- C09K 2211/185: of the platinum group, i.e. Os, Ir, Pt, Ru, Rh or Pd
- H10K 59/12: Active-matrix OLED [AMOLED] displays
- H10K 85/342: {comprising iridium}
- H10K 85/615: {Polycyclic condensed aromatic hydrocarbons, e.g. 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 85/657: {Polycyclic condensed heteroaromatic hydrocarbons}
- 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 2101/30: Highest occupied molecular orbital [HOMO], lowest unoccupied molecular orbital [LUMO] or Fermi energy values
- H10K 2101/40: Interrelation of parameters between multiple constituent active layers or sublayers, e.g. HOMO values in adjacent layers
- H10K 2101/80: {Composition varying spatially, e.g. having a spatial gradient}
- H10K 2101/90: {Multiple hosts in the emissive layer}
- C07F: ACYCLIC, CARBOCYCLIC OR HETEROCYCLIC COMPOUNDS CONTAINING ELEMENTS OTHER THAN CARBON, HYDROGEN, HALOGEN, OXYGEN, NITROGEN, SULFUR, SELENIUM OR TELLURIUM (metal-containing porphyrins C07D487/22)
- C09K: MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
- H10K: ORGANIC ELECTRIC SOLID-STATE DEVICES

## Abstract

A light-emitting element with high emission efficiency. The light-emitting element includes a first organic compound, a second organic compound, and a guest material. The LUMO level of the first organic compound is lower than the LUMO level of the second organic compound. The HOMO level of the first organic compound is lower than the HOMO level of the second organic compound. The HOMO level of the guest material is higher than the HOMO level of the second organic compound. The energy difference between the LUMO level of the guest material and the HOMO level of the guest material is larger than the energy difference between the LUMO level of the first organic compound and the HOMO level of the second organic compound. The guest material has a function of converting triplet excitation energy into light emission. The first organic compound and the second organic compound form an exciplex.

## Claims

### Claim 1

A light-emitting element comprising:
a first electrode;
a light-emitting layer over the first electrode, the light-emitting layer comprising a first organic compound, a second organic compound and a phosphorescent material; and
a second electrode over the light-emitting layer,
wherein the first organic compound comprises a triazine skeleton,
wherein the second organic compound comprises a carbazol-3-yl group,
wherein the first organic compound and the second organic compound form an exciplex,
wherein the phosphorescent material has a lower triplet excitation energy level than each of the first organic compound and the second organic compound,
wherein a lowest unoccupied molecular orbital level of the first organic compound is lower than a lowest unoccupied molecular orbital level of the second organic compound,
wherein a highest occupied molecular orbital level of the first organic compound is lower than a highest occupied molecular orbital level of the second organic compound,
wherein a highest occupied molecular orbital level of the phosphorescent material is higher than the highest occupied molecular orbital level of the second organic compound, and
wherein an energy difference between a lowest unoccupied molecular orbital level of the phosphorescent material and the highest occupied molecular orbital level of the phosphorescent material is larger than an energy difference between the lowest unoccupied molecular orbital level of the first organic compound and the highest occupied molecular orbital level of the second organic compound.

### Claim 2 (depends on 1)

The light-emitting element according to claim 1, wherein an energy difference between the lowest unoccupied molecular orbital level of the first organic compound and the highest occupied molecular orbital level of the phosphorescent material is larger than or equal to a light emission energy of the phosphorescent material.

### Claim 3 (depends on 1)

The light-emitting element according to claim 1, wherein the energy difference between the lowest unoccupied molecular orbital level of the phosphorescent material and the highest occupied molecular orbital level of the phosphorescent material is larger than a transition energy calculated from an absorption edge of an absorption spectrum of the phosphorescent material by 0.3 eV or more.

### Claim 4 (depends on 1)

The light-emitting element according to claim 1, wherein the energy difference between the lowest unoccupied molecular orbital level of the phosphorescent material and the highest occupied molecular orbital level of the phosphorescent material is larger than a light emission energy of the phosphorescent material by 0.3 eV or more.

### Claim 5 (depends on 1)

The light-emitting element according to claim 1, wherein an emission spectrum of the exciplex comprises a region overlapping with an absorption band on a longest wavelength side of an absorption spectrum of the phosphorescent material.

### Claim 6 (depends on 1)

The light-emitting element according to claim 1, wherein the phosphorescent material comprises iridium.

### Claim 7 (depends on 1)

The light-emitting element according to claim 1,
wherein the phosphorescent material has an emission peak in a blue or green wavelength range.

### Claim 8 (depends on 1)

A display device comprising:
the light-emitting element according to claim 1; and
at least one of a color filter and a transistor.

### Claim 9 (depends on 8)

An electronic device comprising:
the display device according to claim 8; and
at least one of a housing and a touch sensor.

### Claim 10 (depends on 1)

A lighting device comprising:
the light-emitting element according to claim 1; and
at least one of a housing and a touch sensor.