Enhanced performance of OLED based on molecular orientation of emission layer by optimized substrate temperature

Horizontally oriented transition dipole moment (TDM) of the molecule in emission layers (EMLs) can boost out-coupling efficiency, resulting in higher performance organic light-emitting diodes (OLEDs). As known, the substrate temperature ( T_s ) has a significant effect on the TDM of molecules. In this paper, the doped EMLs deposited with different T_s ranging from 30 to 100 °C were prepared and the corresponding photoluminescence quantum yield (PLQY) and TDM were measured. In addition, these EMLs with different T_s were employed to the OLED devices. The best luminous efficiency (51.4 cd/A), power efficiency (68.9 lm/W) and external quantum efficiency (EQE) (19.5