Balanced white organic light-emitting diode with non-doped ultra-thin emissive layers based on exciton management

Abstract

The non-doped ultra-thin emissive layer (EML) is a promising novel structure for fabricating organic light-emitting diodes (OLEDs). We attempt to perform exciton management in order to obtain a highly efficient and balanced light-emitting phosphorescent red–green–blue (RGB) white OLED (WOLED). These studies include optimization of the locations of the three RGB EMLs based on investigations concerning the spatial distribution of excitons, along with the energy transfer mechanisms between different materials. More importantly, by introducing a 1,1-bis((di-4-tolylamino)phenyl) cyclohexane (TAPC) interlayer, which acts as a hole-trapping layer, a redistribution of excitons is realized, giving rise to a more balanced white light emission. This simple method is an efficient way to adjust the exciton distribution, and could therefore be used in future OLED devices.