Light-emitting element, light-emitting device, electronic appliance, and lighting device

US9368742B2 · kind B2 · utility

Assignee

• Semiconductor Energy Laboratory Co., Ltd. · JP

Inventors

• Takuya Kawata · Atsugi, JP
• Nobuharu Ohsawa · Yokohama, JP
• Yusuke Nonaka · Yokohama, JP
• Takahiro Ishisone · Yokohama, JP
• Satoshi Seo · Yokohama, JP

Key dates

• Filing date: Nov 20, 2014
• Grant date: Jun 14, 2016
• Expiry date: Nov 20, 2034

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y02E10/549

Abstract

A light-emitting element includes a stack of a first light-emitting layer emitting fluorescent light and a second light-emitting layer emitting phosphorescent light between a pair of electrodes. The second light-emitting layer includes a first layer in which an exciplex is formed, a second layer in which an exciplex is formed, and a third layer in which an exciplex is formed. The second layer is located over the first layer, and the third layer is located over the second layer. An emission peak wavelength of the second layer is longer than an emission peak wavelength of the first layer and an emission peak wavelength of the third layer.