High Efficiency Green Fluorescent Dopant Through the Optimized Side Group for Organic Light Emitting Diodes.

OLED light emitting materials have a molecular size corresponding to the nano scale and are converted into light energy when given electrical energy. The new green fluorescent dopant material was successfully synthesized by using anthracene as a central core and introducing a methyl group and tert-butyl group at various positions as diphenylamine group. Two compounds are N,N,N,N-tetraphenylanthracene-9,10-diamine (TAD) and N,N-bis(4-(tert-butyl) phenyl)-N,N-di-o-tolylanthracene-9,10-diamine (-Tb-o-Me-TAD). The synthesized material emits green light with the maximum wavelengths of 508 and 523 nm. -Tb-o-Me-TAD shows excellent PLQY of 86.2% in solution state. When the synthesized material was used as a dopant in a device, TAD showed current efficiency (CE) of 17.71 cd/A and external quantum efficiency (EQE) of 6.11%. The device using -Tb-o-Me-TAD dopant exhibited current efficiency (CE) of 24.24 cd/A and external quantum efficiency (EQE) of 7.27%.