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

•The non-doped ultra-thin emissive layer (EML) is promising for fabricating OLEDs.•We investigate efficient and balanced light-emitting phosphorescent RGB white OLED.•Locations of the three RGB EMLs are optimized based on exciton spatial distribution.•More balanced white light emission is realized via a TAPC hole-trapping interlayer.•Provides an efficient exciton distribution adjustment method for future devices.

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.

Graphical abstractThe locations of emissive layers (EMLs) were optimized to give rise to white emission. TAPC hole-trapping interlayer was introduced to acquire more balanced emission.Figure optionsDownload full-size imageDownload as PowerPoint slide