title: Highly efficient and stable organic light-emitting diodes with a greatly reduced amount of phosphorescent emitter.
abstract: Organic light-emitting diodes (OLEDs) have been intensively studied as a key technology for next-generation displays and lighting. The efficiency of OLEDs has improved markedly in the last 15 years by employing phosphorescent emitters. However, there are two main issues in the practical application of phosphorescent OLEDs (PHOLEDs): the relatively short operational lifetime and the relatively high cost owing to the costly emitter with a concentration of about 10% in the emitting layer. Here, we report on our success in resolving these issues by the utilization of thermally activated delayed fluorescent materials, which have been developed in the past few years, as the host material for the phosphorescent emitter. Our newly developed PHOLED employing only 1 wt% phosphorescent emitter exhibits an external quantum efficiency of over 20% and a long operational lifetime of about 20 times that of an OLED consisting of a conventional host material and 1 wt% phosphorescent emitter.
authors.affiliation: Japan Broadcasting Corporation (NHK), Science &Technology Research Laboratories, 1-10-11 Kinuta, Setagaya-ku, Tokyo 157-8510, Japan.
authors.forename: Hirohiko
authors.initials: H
authors.lastname: Fukagawa
authors.affiliation: Japan Broadcasting Corporation (NHK), Science &Technology Research Laboratories, 1-10-11 Kinuta, Setagaya-ku, Tokyo 157-8510, Japan.
authors.forename: Takahisa
authors.initials: T
authors.lastname: Shimizu
authors.affiliation: Tokyo University of Science, 1-3 Kagurazaka, Tokyo 162-8610, Japan.
authors.forename: Taisuke
authors.initials: T
authors.lastname: Kamada
authors.affiliation: Tokyo University of Science, 1-3 Kagurazaka, Tokyo 162-8610, Japan.
authors.forename: Shota
authors.initials: S
authors.lastname: Yui
authors.affiliation: Nippon Shokubai Co., Ltd., 5-8 Nishi Otabi-cho, Suita, Osaka, 564-8512, Japan.
authors.forename: Munehiro
authors.initials: M
authors.lastname: Hasegawa
authors.affiliation: Nippon Shokubai Co., Ltd., 5-8 Nishi Otabi-cho, Suita, Osaka, 564-8512, Japan.
authors.forename: Katsuyuki
authors.initials: K
authors.lastname: Morii
authors.affiliation: Japan Broadcasting Corporation (NHK), Science &Technology Research Laboratories, 1-10-11 Kinuta, Setagaya-ku, Tokyo 157-8510, Japan.
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Yamamoto