ITO-free and air stable organic light-emitting diodes using MoO3:PTCDA modified Al as semitransparent anode

Abstract

Ultrathin Al combined with a buffer layer of MoO₃ doped perylene-3,4,9,10-tetracarboxylic dianhydride (PTCDA) has been demonstrated as an efficient semitransparent anode in OLED. The ITO-free OLED utilizing this composite anode exhibits a low turn on voltage of 2.6 V and a high current efficiency of 5.6 cd A⁻¹. Based on accelerated degradation tests, a device half-life of about 945 h was obtained at an initial device luminance of 100 cd m⁻². The charge transfer (CT) complexes formed between MoO₃ and PTCDA played a critical role in promoting hole injection. The buffer layer also kept a smooth and thermal stable morphology, which benefits the stability of OLED greatly.