Multi-Functional Molecular Switches Based on Photochromic Dithienylethenes

Photochromic materials are those which can undergo reversible photo-switches between two different states or isomers upon alternative irradiation with different wavelengths of light accompanied by distinct photophysical and photochemical properties. Inspired by their special photo-switchable characteristics, a variety of light-driven functional materials have been exploited, such as ultrahigh-density optical data storage, molecular switches, logic gates, molecular wires, optic/electronic devices, multi-photon devices, surface/nanoparticle devices, liquid crystals, bio-imaging and so on. Apart from these, further creation of optoelectronic and photo-optical devices based on photochromic molecular switches which operate at both molecular and supramolecular levels have recently attracted many attentions. Thus photo-switchable compounds also have played an important role in sensing, self-assembly, aggregation-induced enhanced emission and photo-controlled biological systems. In particular, dithienylethene derivatives are one of the most promising families of photochromic compounds due to their excellent thermal-stability, remarkable fatigue-resistance, rapid response and fairly high photocyclization quantum yields as well as reactivity in the solid state. According to our recent research achievements, this article provides an overview of recent exciting progress mainly in the field of photochromic dithienylethene derivatives, from systems in solution to modified functional surfaces. Furthermore, based on current development of these photo-switchable systems, further development as well as existing challenges are also discussed and put in prospect.