Visible Light-induced Emission Enhancement in Aggregates of an Azobenzene Derivative

The aggregation-induced emission (AIE) behaviors of an azobenzene derivative with two naphthalenes were studied by spectroscopic and microscopic measurements. The transazobenzene derivative exhibited clear AIE due to ordered aggregation, whereas the cis isomer did not show such AIE because it was a liquid. The nonemissive cis isomers in the liquid state underwent photoisomerization into trans isomers upon visible light irradiation, leading to emission enhancement due to the formation of ordered aggregates of trans isomers.