Organic light-emitting devices with saturated red emission using 6,13-diphenylpentacene

Abstract

Organic electroluminescent devices with saturated red emission were developed using 6,13-diphenylpentacene (DPP) doped into tris(8-hydroxyquinolinato) aluminum III (Alq3). DPP exhibits a narrow emission spectrum giving rise to a saturated red peak, centered around 625 nm, with excellent chromaticity coordinates (x=0.63 and y=0.34) in accordance with the Commission Internationale de l’Eclairage. An absolute photoluminescence (PL) quantum yield (φPL) of ∼30% was measured for a composite film of 0.55 mol % of DPP doped into Alq3. An electroluminescence (EL) quantum efficiency of 1.3% at 100 A/m2, close to the estimated theoretical limit (1.5%), was measured for an unoptimized device structure that consists of an active emissive layer sandwiched between hole- and electron-transport layers. In addition, the EL quantum efficiency is constant or stable over a wide range of current densities (1–1000 A/m2) or luminance values (1–1000 cd/m2).