Autonomous passive light tracking utilizing single-wall carbon nanotube enhanced opto-thermo-mechanical elastomer actuators

We have developed novel opto-thermo-mechanical actuators by effectively distributing a significant amount of single-wall carbon nanotube (SWCNT, up to 0.7%w/w) into liquid crystal elastomer (LCE) matrices. These SWCNT/LCE actuators exhibit a great potential to be utilized in MEMS applications, as they respond to a wide spectrum of visible/near-infrared light, and possess a large reversible compressive strain (up to 35%) when stimulated. Autonomous and passive light tracking is demonstrated here as one of the applications. With a simple design, the actuators are able to adaptively tilt a solar cell towards the light source by a degree of ~15° (with an incident light intensity of 1.6 kW/m²). As a result, the photocurrent output of the solar cell is significantly enhanced (up to 247.10%) without any other control system or external energy source.