A cyanostilbene-based molecule with aggregation-induced emission properties: amplified spontaneous emission, protonation effect and electroluminescence

A terpyridine-substituted cyanostilbene derivative (Z)-2-(4′-([2,2′:6′,2″-terpyridin]-4′-yl)-[1,1′-biphenyl]-4-yl)-3-phenylacrylonitrile (CNSTPy) was synthesized and characterized. The compound exhibits remarkable aggregation-induced emission phenomenon and its single crystal shows a blue emission with fluorescent efficiency as high as 45%. Based on its aggregation state behavior, multiple applications towards exploring its lasing, fluorescence switching and electroluminescence properties were realized. Amplified spontaneous emission (ASE) was observed from the crystal and verified by the variable pump strip method, with a threshold value of ~1.5 mJ cm−2. The protonation/deprotonation processes accompanied by the formation of different molecular aggregation structure result in the distinct blue and yellow emissions. Additionally, the molecule also shows a moderate electroluminescence performance.