Non-doped red or blue electroluminescent materials based on fluorenyl-triarylamines with fumaronitrile or fluorene bridge

Abstract

A donor–acceptor red fluorescent dye bis(4-(N-(9,9-diethyl-2-fluorenyl)-3,5-dimethyl-phenylamino)phenyl)fumaronitrile (FMPAFN), and a blue fluorescent dye 2,7-bis(N-2-(9,9-diethylfluorenyl)-3,5-dimethylphenylamino)-9,9-diethylfluorene (FMPAEF), were synthesized, characterized, and used as active materials in non-doped electroluminescent devices. Emission peaks from three-layered or four-layered devices using FMPAFN dye centered at 680 or 684nm with their Commision Internationale de I'Eclairage (CIE) color coordinates of (0.671, 0.310) or (0.673, 0.309). Current efficiencies of 1.89 or 3.55cd/A for the FMPAFN devices were achieved, respectively. Similar non-doped three-layered or four-layered devices based on blue FMPAEF dye emitted at 424 or 456nm with full widths at half maximum of 63 and 101nm and CIE (x,y) of (0.181, 0.138) or (0.185, 0.189), respectively. Current efficiencies of the FMPAEF devices were 0.57 or 1.04cd/A. In these devices, both dyes are multifunctional, acting as emitters as well as hole-transporting materials. The emission colors were tuned by both the non-planar arylamino group and the centric core (fumaronitrile or fluorene bridge), revealing potential applications in electroluminescent devices.