Mechanochromic luminescence and color-tunable light-emitting devices of triphenylamine functionalized benzo[d,e]benzo[4,5] imidazo[2,1-a]isoquinolin-7-one

A novel molecule 3-(4-diphenylaminophenyl)-benzo[d,e]benzo[4,5]imidazo[2,1-a]isoquinolin-7-one (3-TPA-BBI) is synthesized and found to exhibit mechanochromic luminescence properties. Its photoluminescence can be reversibly switched between orange and yellow upon external stimuli. More interestingly, a non-doped device utilizing 3-TPA-BBI as the emitter exhibits unprecedented color-tunable electroluminescence upon heat treatment.