New type of electronic skin could allow future robots to ‘see’

The development involves a new method of printing microscale semiconductors, made from gallium arsenide, onto a flexible plastic surface.

Previously, gallium arsenide has been used on rigid surfaces to create high-performance electronics. The team at Glasgow are among the first to find a way to use it on a flexible substrate.

They adapted their existing roll printing system (the team previously developed a method of printing silicon circuitry directly onto the surface of flexible plastic) to print gallium arsenide electronics onto a flexible surface using arrays of wires that are 15 micrometres in width.

This resulted in a photodetector capable of sensing light from ultraviolet range, through the visible portion of the spectrum, to the infrared – all requiring extremely low power.

The system takes just 2.5 milliseconds to measure light and eight milliseconds to recover.

During testing, the material demonstrated no significant loss in performance over the course of 500 cycles of bending and twisting.

Professor Ravinder Dahiya of the University of Glasgow’s James Watt School of Engineering is the leader of the Bendable Electronics and Sensing Technologies (BEST) research group, which developed the skin.

Professor Dahiya said: “We’ve been working for a number of years now to advance the capabilities of flexible electronics. We’ve found new ways to print electronics directly onto flexible surfaces, built electronic skin capable of feeling ‘pain’, and developed bendable electronics which can be powered by the sun or human sweat.

“This latest development is the first time we’ve been able to print gallium arsenide onto flexible surfaces, opening up new avenues for our research.

“In the future, this type of light-sensitive flexible material could lend new abilities to robots. Mechanical arms used for manufacturing in light-sensitive environments, for example, could become capable of detecting when conditions change, and the safety or effectiveness of their work is put at risk. Flexible, broad-spectrum photodetectors could also find use in a wide range of wireless communication technologies, where the fast transmission and response speeds we’ve tested are always in demand."

Ayoub Zumeit and Abhishek Dahiya from the BEST group, co-authors of the paper, added: “It could even be used to develop a wearable patch for humans to use to monitor exposure to UV light during sunny days, and provide a warning when users are at risk of getting sunburned.”