Dual role of a pyrene derivative as a hole transport material and an emitter in blue fluorescent organic light-emitting diodes

A pyrene derivative, N1,N6-di([1,1′-biphenyl]-4-yl)-N1,N6-bis(9,9-dimethyl-9H-fluoren-2-yl)pyrene-1,6-diamine(PyFB), was investigated as a dual function organic material working as a hole transport material and a sky blue emitter at the same time. A pyrene core was modified with an aromatic amine moiety substituted with a fluorene and a biphenyl unit. The pyrene derived PyFB material showed the highest occupied molecular orbital of −5.5 eV and better hole transport properties than a common hole transport layer. The PyFB also worked as the sky blue emitter and a sky blue organic light-emitting diode developed using the PyFB emitter demonstrated a high external quantum efficiency of 8.5% and a very long lifetime of 56 h up to 95% of initial luminance at 500 cd/m².