title: High Power Efficiency Blue-to-Green Organic Light-Emitting Diodes Using Isonicotinonitrile-Based Fluorescent Emitters.
abstract: Herein, 9,10-dihydro-9,9-dimethylacridine (Ac) or phenoxazine (PXZ)-substituted isonicotinonitrile (INN) derivatives, denoted as 2AcINN, 26AcINN, and 26PXZINN, were developed as a series of thermally activated delayed fluorescence (TADF) emitters. These emitters showed reasonably high photoluminescence quantum yields of 71-79 % in the host films and high power efficiency organic light-emitting diodes (OLEDs). Sky-blue emitter 26AcINN exhibited a low turn-on voltage of 2.9 V, a high external quantum efficiency (ηext) of 22 %, and a high power efficiency (ηp) of 66 lm W-1with Commission Internationale de l'Eclairage (CIE) chromaticity coordinates of (0.22, 0.45), whereas green emitter 26PXZINN exhibited a low turn-on voltage of 2.2 V, a high ηextof 22 %, and a high ηpof 99 lm W-1with CIE chromaticity coordinates of (0.37, 0.58). These performances are among the best for TADF OLEDs to date.
authors.affiliation: Research Center for Organic Electronics (ROEL), Yamagata University, 4-3-16 Jonan, Yonezawa, Yamagata, 992-8510, Japan.|Frontier Center for Organic Materials (FROM), Yamagata University, 4-3-16 Jonan, Yonezawa, Yamagata, 992-8510, Japan.|Department of Organic Materials Science, Graduate School of Organic Materials Science, Yamagata University, 4-3-16 Jonan, Yonezawa, Yamagata, 992-8510, Japan.
authors.forename: Hisahiro
authors.identifier: http://orcid.org/0000-0002-1312-0111
authors.initials: H
authors.lastname: Sasabe
authors.affiliation: Department of Organic Materials Science, Graduate School of Organic Materials Science, Yamagata University, 4-3-16 Jonan, Yonezawa, Yamagata, 992-8510, Japan.
authors.forename: Natsuki
authors.initials: N
authors.lastname: Onuma
authors.affiliation: Department of Organic Materials Science, Graduate School of Organic Materials Science, Yamagata University, 4-3-16 Jonan, Yonezawa, Yamagata, 992-8510, Japan.
authors.forename: Yuji
authors.initials: Y
authors.lastname: Nagai
authors.affiliation: Department of Organic Materials Science, Graduate School of Organic Materials Science, Yamagata University, 4-3-16 Jonan, Yonezawa, Yamagata, 992-8510, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Ito
authors.affiliation: Research Center for Organic Electronics (ROEL), Yamagata University, 4-3-16 Jonan, Yonezawa, Yamagata, 992-8510, Japan.|Frontier Center for Organic Materials (FROM), Yamagata University, 4-3-16 Jonan, Yonezawa, Yamagata, 992-8510, Japan.|Department of Organic Materials Science, Graduate School of Organic Materials Science, Yamagata University, 4-3-16 Jonan, Yonezawa, Yamagata, 992-8510, Japan.
authors.forename: Junji
authors.initials: J
authors.lastname: Kido
keywords: OLEDs; donor-acceptor systems; fluorescence; power efficiency; solid-state emission