Optical Control of Aggregation-Induced Emission Shift by Photoisomerizable Precipitant in a Liquid Droplet Microresonator

摘要

Emission-switchable fluorophores often include stimuli-responsive unitsin their molecular structures. This strategy works well, but the applicablecompounds are limited to the derivatives of several kinds of photochromicmolecules such as diarylethene, azobenzene, and spiropyran. Here, thiswork presents a simple methodology based on a photoresponsive precipitantfor achieving color-switchable photoluminescence. A luminescent dye,cyano-substituted oligo(phenylenevinylene) (COPV), features both twistedintramolecular charge transfer and aggregation-induced emission shiftproperties, leading to the change in the luminescence color from green tored upon precipitation. The COPV, together with photoisomerizable precipitantazobenzene (C6), is doped into spherical droplets of epoxy resin (ER) ina liquid state. The photoisomerization of C6 induced by UV irradiation andheating alternatively precipitates out and dissolves COPV in ER and changesthe photoluminescence color, while maintaining the optical microresonatorproperties. This study will open a promising way for assembling/disassemblingnovel emission color-switchable systems.