Spirally configured cis-stilbene/fluorene hybrids as ambipolar, fluorescent materials for organic light emitting diode applications

Abstract

A new class of cis-stilbene/fluorene spiro hybrid systems with paired diphenylamino donor and cyano, N-phenylbenzimidazole, dimesitylboranyl, or β,β-diphenylethenyl acceptor units was synthesized as ambipolar materials for organic light-emitting diode applications. When coupled with hole transporting 4,4′-bis(1-naphthylphenylamino)-1,1′-biphenyl (α-NPB) and electron transporting 2,2′,2′′-(1,3,5- benzenetriyl)-tris(1-phenyl-1-H-benzimidazole) layers, they served as one of the best bluish green and pure green emitting layers with excellent external quantum efficiencies of 3.9-5.2%, electroluminescent brightness of 2202-3069 cd m-2, luminance efficiencies of 11.0-15.8 cd A-1, and power efficiencies of 5.7-6.6 lm W-1 at 20 mA cm-2, which were about 2-3 times better than those based on standard α-NPB/tris(8- hydroxyquinoline)aluminum bilayer devices. © 2013 The Royal Society of Chemistry.