Photothermally Promoted Photoisomerization of Naphthopyran-Based Dyes to Achieve Sensitive Photodeformation under Sunlight

The exploration of photodeformation materials toward sunlight is essential for their application in soft robots and medical technology. However, until now, the sunlight driven deformation is still confronted with challenges, which is hard to be realized with high sensitivity by either photothermal or photoisomerization process independently. In this text, through the rational combination of photothermal and photoisomerization properties by naphthopyran-based dyes, the sunlight-driven contraction can be achieved with good fatigue resistance. Moreover, through the precise modulation of molecular configurations and electronic properties, the sensitive photodeformation toward sunlight has been achieved with a contraction of 50% and a bending angle of 118 degrees. This work provides a convenient approach to construct sunlight-driven soft actuators via a photothermally promoted photoisomerization process.