Organic fluorophores with unique photophysical properties that converting the triplet excitons to singlet excitons, are desired to improve the efficiencies of organic light-emitting diodes (OLEDs). Here, two new anthracene-based emitters pipdAnCz and pipdAnTPA, with proper donor and acceptor substituents are designed and synthesized. The theoretical calculation and experimental results demonstrate that both pipdAnCz and pipdAnTPA possess hot exciton and triplet-triplet annihilation (TTA) characteristics, which can convert the triplet excitons to singlet excitons from the high-lying triplet energy levels (Tn) and the lowest triplet energy level (T1) respectively. Due to its relative higher photoluminescence quantum yields (PLQYs), the pipdAnTPA based non-doped device achieved a maximum external quantum efficiency (EQEmax) of 6.43% with an exciton utilization efficiency (EUE) of 72%. Further device physics study reveal that the hot exciton process is the dominant mechanism, assisted by TTA process, to convert the triplet excitons, especially for the pipdAnTPA based device.
