Recent progress in all-visible-light-triggered diarylethenes

Photochromic materials have recently attracted much attention in optoelectronic devices and optical storage systems because of their excellent reversible photoresponse performance. Among them, diarylethene has been widely studied for its excellent thermal stability, rapid photoresponsibility, robust fatigue resistance, and good performances in solution and solid states. However, one serious limitation to the application of such molecules is that the switch must be triggered by UV light, which shows great damage and low penetration to optical equipment and biological tissues. This review will highlight recently developed strategies that can be used for developing visible-light-activated diarylethenes, such as extended pi-conjugation system, triplet sensitization, upconverting nanoparticles, multiphoton absorption, intermolecular electron transfer induced by supramolecular self-assembly, and intramolecular proton transfer. Such all-visible-light-triggered molecular switches will tremendously extend their applications for photoresponsive optoelectronics and photopharmacology in the future.