Oscillating light engine realized by photothermal solvent evaporation
Jinɡjinɡ Li, Linlin Mou, Zunfeng Liu, Xiang Zhou, Yongsheng Chen
Abstract
Abstract Continuous mechanical work output can be generated by using combustion engines and electric motors, as well as actuators, through on/off control via external stimuli. Solar energy has been used to generate electricity and heat in human daily life; however, the direct conversion of solar energy to continuous mechanical work has not been realized. In this work, a solar engine is developed using an oscillating actuator, which is realized through an alternating volume decrease of each side of a polypropylene/carbon black polymer film induced by photothermal-derived solvent evaporation. The anisotropic solvent evaporation and fast gradient diffusion in the polymer film sustains oscillating bending actuation under the illumination of divergent light. This light-driven oscillator shows excellent oscillation performance, excellent loading capability, and high energy conversion efficiency, and it can never stop with solvent supply. The oscillator can cyclically lift up a load and output work, exhibiting a maximum specific work of 30.9 × 10 −5 J g −1 and a maximum specific power of 15.4 × 10 −5 W g −1 under infrared light. This work can inspire the development of autonomous devices and provide a design strategy for solar engines.