title: Mixing of phosphorescent and exciplex emission in efficient organic electroluminescent devices.
abstract: We fabricated a yellow organic light-emitting diode (OLED) based on the star-shaped donor compound tri(9-hexylcarbazol-3-yl)amine, which provides formation of the interface exciplexes with the iridium(III) bis[4,6-difluorophenyl]-pyridinato-N,C2']picolinate (FIrpic). The exciplex emission is characterized by a broad band and provides a condition to realize the highly effective white OLED. It consists of a combination of the blue phosphorescent emission from the FIrpic complex and a broad efficient delayed fluorescence induced by thermal activation with additional direct phosphorescence from the triplet exciplex formed at the interface. The fabricated exciplex-type device exhibits a high brightness of 38 000 cd/m(2) and a high external quantum efficiency.
authors.affiliation: Lviv Polytechnic National University , S. Bandera 12, 79013 Lviv, Ukraine.
authors.forename: Vladyslav
authors.initials: V
authors.lastname: Cherpak
authors.forename: Pavlo
authors.initials: P
authors.lastname: Stakhira
authors.forename: Boris
authors.initials: B
authors.lastname: Minaev
authors.forename: Gleb
authors.initials: G
authors.lastname: Baryshnikov
authors.forename: Evgeniy
authors.initials: E
authors.lastname: Stromylo
authors.forename: Igor
authors.initials: I
authors.lastname: Helzhynskyy
authors.forename: Marian
authors.initials: M
authors.lastname: Chapran
authors.forename: Dmytro
authors.initials: D
authors.lastname: Volyniuk
authors.forename: Zenon
authors.initials: Z
authors.lastname: Hotra
authors.forename: Asta
authors.initials: A
authors.lastname: Dabuliene
authors.forename: Ausra
authors.initials: A
authors.lastname: Tomkeviciene
authors.forename: Lesya
authors.initials: L
authors.lastname: Voznyak
authors.forename: Juozas Vidas
authors.initials: JV
authors.lastname: Grazulevicius
keywords: blue iridium complex; density functional theory; organic light-emitting diode; reverse intersystem crossing; starshaped carbazole-based compound; thermally activated delayed fluorescence