Tailoring the spectra of white organic light-emitting devices by trap effect of a concentration-insensitive dopant

Abstract

Highly efficient phosphorescent organic light-emitting devices (PhOLEDs) had been fabricated by using a novel iridium complex, bis[2-(3 ′, 5 ′ -di-tert-butylbiphenyl-4-yl)benzothiazolato-N, C 2 ′ ]iridium(III) (acetylacetonate) [(tbpbt)r(acac)], as the emitter. With a wide doping ratio ranging from 15 wt% to 25 wt%, the PhOLEDs maintained a comparable high performance, indicating concentration-insensitive property of the (tbpbt)r(acac). On the basis of the unique characteristic of concentration insensitivity, the application of this phosphor was explored by fabricating white organic light-emitting devices (WOLEDs) with altered doping ratio, indicating that trap effect of (tbpbt)r(acac) could effectively tailor WOLEDs spectra. Typically, a high-power efficiency, current efficiency, and external quantum efficiency of 30.0 lm/W, 38.8 cd/A, 18.1%, were achieved by 20 wt% doped WOLEDs. © 2013 Qi Wang et al.