Highly efficient solution-processed host-free organic light-emitting diodes showing an external quantum efficiency of nearly 18% with a thermally activated delayed fluorescence emitter

Abstract We demonstrate solution-processed host-free organic light-emitting diodes (OLEDs) using a thermally activated delayed fluorescence emitter 10-[4-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl]-9,9-dimethylacridan (DMAC-TRZ). A spin-coated neat DMAC-TRZ film shows weak concentration quenching, leading to a high photoluminescence quantum yield (PLQY) of 84%. OLEDs containing a neat film of DMAC-TRZ display a maximum external quantum efficiency (EQE) of 17.6%. Both the PLQY and EQE are the highest reported for solution-processed host-free films and OLEDs, respectively. In addition, the OLEDs exhibit an EQE of 16.8% at high luminance (over 400 cd m −2 ).