Mechanical effects of elastic crystals driven by natural sunlight and force.

Flexible crystals that can capture solar energy and convert it into mechanical energy are promising for a wide range of applications in areas such as information storage, and actuators, but obtaining them remains a challenge. Herein, the elastic crystal of a barbiturate derivative was found to be an excellent candidate, and showed plastic bending behavior under natural sunlight irradiation. 1H NMR and high-resolution mass spectrum data of the microcrystals before and after light irradiation demonstrated that the light-induced [2+2] cycloaddition was the driving force for the photomechanical effects. Interestingly, the crystals remained well elastic properties after light irradiation. This is the first reported crystal that can be driven by natural sunlight, and has both photomechanical properties and elasticity. Furthermore, we could regulate the passive light output direction of the crystals and transport objects by applying mechanical forces and light.