A tunable photoluminescence system consisting of liquid-crystalline trans-alkoxy-nitrostilbenes with n-alkyl chains

A correlation between molecular arrangements and photoluminescence properties of trans-alkoxy-nitrostilbenes with n-alkyl chains was elucidated in their crystalline and liquid-crystalline states. In the former states, alternately stacked acceptor–acceptor assemblies caused fluorescence emission with eight percent quantum yield at maximum, while the donor–acceptor ones with less than one percent. Heat treatment yielded their liquid-crystalline assemblies comprising J-aggregation with yellow emissions. The emissions were red-shifted by about 20–40 nm as compared with those of their crystalline assemblies. Such temperature-dependent structural changes enable us to tune the emission colors.