Photoinduced stepwise bending behavior of photochromic diarylethene crystals

Diarylethene crystals were found to exhibit photoinduced stepwise bending behavior. The bending rate changed significantly during continuous irradiation with ultraviolet (UV) light. This is a new type of photo-mechanical motion reported previously for various photoresponsive molecular crystals. Furthermore, the delayed bending behavior was observed even after UV light was turned off. The mechanism for the stepwise bending is discussed.