Smart Photochromic Materials Triggered with Visible Light

Molecular photoswitches reversibly convert the energy of light into a variety of structural changes at the molecular level. They can be integrated into smart materials with broad range of applicability. While most photochromic systems require UV light for activation, application of photoswitches operational entirely within the visible or NIR range of light brings considerable benefits, such as biocompatibility, better light penetration through the material, propelling with sunlight, or a possibility to design dual systems that are mutually activated with UV or visible light frequencies for two distinct functions. In this Review, we discuss the most relevant classes of molecular photoswitches, and demonstrate a selection of photochromic polymers, gels, porous materials, surfaces, energy-storing materials and other systems triggered with visible light.