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US 2021/0343965 A1Published application
Light-Emitting Device, Light-Emitting Apparatus, Electronic Device, and Lighting Device
AssigneeSemiconductor Energy Laboratory Co., Ltd.
InventorSatoshi Seo
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Abstract
To provide a light-emitting device not only including a light-emitting layer in which energy is efficiently transferred from a host material to a guest material but also having high reliability. The light-emitting device not only includes a light-emitting layer in which the T1 levels and the S1 levels of a host material and a guest material fall within certain ranges so that energy can be efficiently transferred from the host material to the guest material and but also has improved reliability.
Claims21
A light-emitting device comprising:
- an EL layer between a pair of electrodes,
- wherein the EL layer includes a light-emitting layer,
- wherein the light-emitting layer contains a first organic compound, a second organic compound, and a light-emitting substance,
- wherein a T1 level (TD(edge)) and a T1 level (TH(edge)) satisfy Formula (1):
- 0.07 eV≤TH(edge)−TD(edge)≤0.27 eV (1),
- wherein a difference between an S1 level (S′H(edge)) and the T1 level (TH(edge)) satisfies Formula (2):
- 0.02 eV≤S′H(edge)−TH(edge)≤0.5 eV (2),
- wherein the T1 level (TH(edge)) represents the lower of T1 levels derived from emission edges on a short wavelength side of phosphorescent spectra of the first organic compound and the second organic compound,
- wherein the T1 level (TD(edge)) represents a T1 level derived from an absorption edge of an absorption spectrum of the light-emitting substance, and
- wherein the S1 level (S′H(edge)) represents an S1 level derived from an emission edge on a short wavelength side of a fluorescent spectrum of a mixed material of the first organic compound and the second organic compound.
7 more elements
A light-emitting device comprising:
- an EL layer between a pair of electrodes,
- wherein the EL layer includes a light-emitting layer,
- wherein the light-emitting layer contains a first organic compound, a second organic compound, and a light-emitting substance,
- wherein a T1 level (TD(edge)) and a T1 level (TH(edge)) satisfy Formula (3):
- 0.07 eV≤TH(edge)−TD(edge)≤0.17 eV (3),
- wherein a difference between an S1 level (S′H(edge)) and the T1 level (TH(edge)) satisfies Formula (4):
- 0.2 eV≤S′H(edge)−TH(edge)≤0.5 eV (4),
- wherein the T1 level (TH(edge)) represents the lower of T1 levels derived from emission edges on a short wavelength side of phosphorescent spectra of the first organic compound and the second organic compound,
- wherein the T1 level (TD(edge)) represents a T1 level derived from an absorption edge of an absorption spectrum of the light-emitting substance, and
- wherein the S1 level (S′H(edge)) represents an S1 level derived from an emission edge on a short wavelength side of a fluorescent spectrum of a mixed material of the first organic compound and the second organic compound.
7 more elements
Dependencies are inferred from the claim text.