High-efficiency deep-blue emitter consisting of a chrysene core and optimized side groups

Abstract

Five emitters of blue light were synthesized, three of them for the first time, by using a chrysene core chromophore with its high photoluminescence quantum yield (PLQY) and wide bandgap. The emission was optimized by testing various electron-donating diphenylamine (DPA)-containing side groups differing in the numbers, sizes, and substitution positions of alkyl groups attached to the DPA groups. All materials showed excellent PLQY values and deep-blue emissions in the solution state. When the material was, respectively, applied as dopants in the emitting layers of organic light-emitting diode devices, high current efficiency values of over 6 cd/A and external quantum efficiency (EQE) values of over 6% were achieved in the deep-blue or real-blue region. Of these five materials, bis-(4-tert-butyl-phenyl)-di-o-tolylchrysene-6,12-diamine (TBTAC) showed the highest EQE of 7.81%, and Commission Internationale de L'Eclairage coordinates of (0.143, 0.095).