Efficient blue organic light-emitting diodes based on triphenylimidazole substituted anthracene derivatives

A series of new blue emissive materials based on the conjugates of highly fluorescent diaryl anthracene and electron-transporting triphenylimidazole moieties: were designed and synthesized successfully. These materials exhibit good film-forming properties and excellent thermal stabilities. With respect to the three layer device 2 using 1-NaCBI as the emitting layer, its maximum current efficiency reaches 3.06 cd A−1 with Commission Internationale del'Eclairage (CIE) coordinates of (0.149, 0.092). More interestingly, sky blue doped device 5 based on 1-NaCPI achieved a maximum current efficiency of 15.53 cd A−1 and a maximum external quantum efficiency of 8.15%, high EQE has been proved to be induced by the up-conversion of a triplet excited state.