Heliotracking Device using Liquid Crystalline Elastomer Actuators

Abstract Many living organisms in nature respond to light stimulus and track the light source. Inspired by this, and to maximize the light‐harvesting ability of solar cells, here, a spontaneous helio‐tracking device based on the differential light‐induced actuation of liquid crystalline elastomers (LCEs) is demonstrated. The synthesis of the actuator material involves a robust thiol “click” polymerization, while the addition of indocyanine green (ICG) dye imparts the sensitivity to broad‐spectrum and near‐infrared light. Highly reproducible thermal and photo‐induced linear actuation is demonstrated. The device is based on a freely pivoting payload platform held in place by several linear LCE actuators around the 360° circumference. The side of the device, which is exposed to light, has the actuators contracting and tilting the platform toward the light source. As the light source (e.g., the Sun) is moving around the device, the platform tilt followed, always exposing the payload face to the light; in the dark, the device recovers its neutral position.