A conjugated hyperbranched polymer constructed from carbazole and tetraphenylethylene moieties: convenient synthesis through one-pot "A2+B4" Suzuki polymerization, aggregation-induced enhanced emission, and application as explosive chemosensors and PLEDs

In this paper, tetraphenylethylene (TPE) units, a well-known aggregation-induced emission (AIE) active group, are utilized to construct the hyperbranched polymer HP-TPE-Cz with carbazole moieties, a good hole-transporting and electroluminescent group, through an "A(2) + B-4'' approach by using a one-pot Suzuki polycondensation reaction. For comparison, its analog linear polymer LP-TPE-Cz, also constructed from these two moieties, was prepared. These two polymers exhibit interesting aggregation-induced emission enhanced (AIEE) behavior and act as explosive chemosensors with high sensitivity both as nanoparticles and in solid state, due to the presence of TPE units. Also, the HP-TPE-Cz PLED device exhibited a remarkably enhanced current efficiency (2.13 cd A(-1)) and luminescence efficiency (5914 cd m(-2)), compared with its analog linear polymer LP-TPE-Cz (1.04 cd A(-1), 1654 cd m(-2)).