High performance blue and white fluorescent organic electroluminescent devices with conventional electron transport material as blue emitter

Abstract

In this study, a feasible device design strategy was reported to achieve efficient blue and white fluorescent organic light-emitting diodes by exploiting a conventional electron transport material as blue emitter. A series of devices were fabricated and investigated by selecting closely matched host materials. The doped blue emitter molecules within a hole dominant light-emitting layer function as both emitting centers and electron transport ladders, thus help to broaden the recombination zone and improve the balance of the carriers. Finally, high performance blue device with the maximum brightness (Bmax), external quantum efficiency (ηext, max) and Commission Internationale de l'Eclairage coordinates (CIEx, y) of 7531 cd/m2, 4.3% and (0.146, 0.148), respectively, was obtained. Furthermore, the optimized white EL device with Bmax, ηext, max and CIEx, y up to 11,315 cd/m2, 5.7% and (0.241, 0.327), respectively, was acquired by adjusting the doping concentrations of fluorescent emitters and the thicknesses of light-emitting layers.