Visible-Light-Driven Photoswitching of AIE-Active Diarylethenes for Super Resolution Imaging.

: Photoswitchable fluorescent diarylethenes are promisingly widely applied in the fields of optical memory, all-optical transistors, bioimaging and super-resolution imaging, etc. However, they are facing the problems of fluorescence quenching at aggregated/solid state, inadequate fluorescence ON/OFF switching ratio and the necessity of UV-light irradiation. Herein, we report a novel kind of high-performance diarylethenes with aggregated-induced emission (AIE) by conjugating two diarylethene groups on one AIE-gen, i.e., TPE-2DTE (blue-green fluorescent) and OTPE-2DTE (orange fluorescence). Their open forms show enhanced fluorescence in aggregated state and solid state. The closed form of TPE-2DTE/OTPE-2DTE was effectively generated upon a short-wavelength visible-light (400 nm-450 nm) irradiation, whose fluoresence was dramatically quenched by intramolecular energy transfer.Remarkably, 405 nm purple irradiation gives the fluorescence ON/OFF ratios of 1196: 1 and 1983: 1 for TPE-2DTE and OTPE-2DTE, respectively. The reverse process can be accomplished after another longer wavelength irradiation such as 621 nm and shows considerable fatigue resistance. Taking advantage of superior photoswitching properties under visible-light irradiations, TPE-2DTE and OTPE-2DTE were used for super-resolution imaging with a high resolution of sub-50 nm. This work offers a guidance to design bright-emission and high-performance all-visible light controlled diarylethene photoswitches for practical applications.