Photoluminescence intensity and polarization modulation of a light emitting liquid crystal via reversible isomerization of an α-cyanostilbenic derivative

• A new optical switch based on AIE-active luminescent liquid crystals was developed.
• The mixture material can emit partially linearly polarized light.
• It is possibly to modulate photoluminescence intensity and its polarization.
• It has the potential to be used in improved optical devices.

We found reversible photo/thermal isomerization of the α-cyanostilbenic derivative (Z)-2-(4-aminophenyl)-3-(4-(dodecyloxy)phenyl)-acrylonitrile, (Z)-CN-APHP, which is accompanied by a large decrease in compatibility when mixed with a nematic liquid crystal. Moreover, a novel optical switch using a CN-APHP doped liquid crystal that emits partially linearly polarized light is investigated. By controlling the trans–cis isomerization of CN-APHP, it is possibly to modulate not only photoluminescence intensity but also its polarization. This could open possibilities to design improved optical devices.