High-voltage photonic switching of dielectric elastomers with amorphous silicon thin-films

Optically-switched composite materials based on semiconducting materials have the potential to simplify the circuitry required to control artificial muscles. This contactless control method has the potential to improve visual technologies by enabling controllable haptic and morphing interfaces. Optically-switched active displays could provide enhanced user interaction, especially for those with visual impairments. Research into morphing interfaces with dielectric elastomer actuators (DEAs) centralizes on segmented electrode architectures that can achieve large active strains in multiple degrees of freedom. However, controlling the activation of multiple electrodes typically requires an array of discrete rigid components (e.g. MOSFETs) as well as the separation of high-voltage power lines and low-voltage control signals. In this work, we develop a photo-switched DEA system that removes the need for wired control signals, reducing complexity. Photonic switching of DEA electrodes is achieved by exploiting the light-dependent resistance of a thin film of deposited amorphous silicon (a-Si). Samples with layer thicknesses of 0.84 μm have been fabricated using plasma enhanced chemical vapor deposition. Breakdown voltages of above 6kV were obtained when using a nonconducting substrate (glass). Preliminary testing of the system shows that voltage swings of up to 865V can be achieved between ambient and direct illumination, producing an out of plane actuation of 2 μm in a weight-biased DEA disc actuator. Further tuning of the electric circuit should lead to larger actuation strains. Future work will focus on the control of multiple DEA electrodes using localized light patterns as well as testing and characterizing other materials to improve the voltage swing across the DEA.