Multifunctional Energy Generating Electronic Skin for Robotics and Wearables

Replicating the functioning of biological skin with touch, temperature sensing etc. is a challenging task. A number of attempts have been made to develop electronic-skin (e-skin), mimicking the morphology and functionality of biological skin. However, powering these sensor-laden systems to ensure continuous operation remains a big challenge. Herein, we present solar cells-based energy generating e-skin (solar skin) and demonstrate how the energy outputs of solar-cells can be innovatively processed for multimodal sensing. Two different approaches are followed. In the first, the generated electrical energy from solar skin under indoor light illumination is used for continuous powering of portable low-power devices. For instance, solar cells generate an energy surplus of >1mW (effective module area of 20 cm2) under white light illumination (4450 lux), which is used for the continuous powering of portable low-powered devices such as array of touch sensors. In the second approach, a solar skin without using dedicated sensors is developed to provide capabilities for touch, temperature, and proximity sensing. This is achieved by reading the variations and energy output patterns of the solar cells. Likewise, solar cells are used to sense multiple parameters including object motion, colour detection (from light wavelength), and ambient temperature (sensitivity about -1.8 mV/C). The accurate tracking of shadow sensing, for an object moving in horizontal and vertical directions with respect to the solar skin with varying speeds (1, 5, and 10 cm/s), we could obtain the information such as the velocity and acceleration of moving object. In this regard, the presented e-skin can also be seen to be having vision capability. The presented work opens exciting avenues into futuristic energy-autonomous e-skins that can “see” and “feel” without need of bulky and toxic batteries to power them.