Constructing a novel single-layer white organic light-emitting device through a new sky-blue fluorescent bipolar host

Abstract

A novel device concept was realized for simple single-layer small-molecule white organic light emitting devices. The single organic active layer here is simply comprised of a newly synthesized sky-blue fluorescent bipolar host (TPASO) and a common orange phosphorescent dopant. Suppressed singlet Föster energy transfer induced by a low-concentration doping and spontaneous high- to low-lying triplet energy transfer, respectively, lead to sky-blue fluorescence from TPASO and orange phosphorescence from the dopant. The resulting two-organic-component device exhibits a low turn-on voltage of 2.4V, maximum current/power efficiencies up to 11.27±0.02cdA−1 and 14.15±0.03lmW−1, and a warm-white CIE coordinate of (0.42, 0.45) at 1000cdm−2.