Next step of photochromic switches?

Bisthienylethenes (BTE) are one of the most promising families of photochromic compounds used in molecular switches because of their fatigue resistance and thermally irreversible properties. Moreover, such molecular switches hold tremendous potential applications in molecular electronic and photonic devices such as optical data storage media, optical limiters, logic gates, molecular wires and sensors. Herein we highlight some recent developments of photochromic bisthienylethene derivatives with large two-photon absorption (TPA) or excellent two-photon excited fluorescence (TPEF) which can be potentially used in three-dimensional (3D) optical data storage media, two-photon switches and photon electronic devices. What's more, we examine some promising approaches on bisthienylethene derivatives such as supramolecular self-assembled structures, coordination with metal and ligands, capping on nanoparticles or assemblies on metal surfaces, which would tune the photochromic properties of photochromic switches for further applications.