Future robots could have electronic skins that can “see” light beyond the range of human eyesight, thanks to a new kind of flexible photodetector.
Image Credit: asharkyu/Shutterstock.com
The ground-breaking innovation was created by a group of engineers from the University of Glasgow, who used a newly invented technique to print microscale semiconductors composed of gallium arsenide on a flexible plastic surface.
Their material has performance comparable to the finest conventional photodetectors now available on the market and can survive hundreds of bending and flexing cycles.
The researchers describe how they created the technology which enables the skin to detect light from a wide range of the electromagnetic spectrum in a new publication in the journal Advanced Materials Technology.
It advances earlier work by the group in which they created a technique for directly printing silicon circuitry onto the surface of flexible plastic, enabling the production of high-performance bendable electronics.
For the creation of high-performance electronics, gallium arsenide is employed in several applications. The Glasgow team, however, is among the first to discover a method of using gallium arsenide on a flexible substrate. Until now, they have mostly been developed on rigid surfaces.
Using arrays of wires that are 15 μm wide, they modified their current roll printing technology to imprint gallium arsenide electronics onto a flexible surface.
This made it possible for them to develop a new kind of flexible photodetector that could detect light at very low power levels in the ultraviolet, visible, and infrared spectrums.
The system has an ultrafast reaction time to light, measuring light in only 2.5 milliseconds and recovering in just 8 milliseconds, which is on performance with the best non-flexible photodetectors presently on the market.
Researchers rigorously put the material through a series of tests in a machine built to bend and twist it hundreds of times in order to evaluate the system’s resilience. After 500 cycles, the material showed no appreciable performance degradation.
The Bendable Electronics and Sensing Technologies (BEST) research team, led by Professor Ravinder Dahiya of the James Watt School of Engineering at the University of Glasgow, created the skin.
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.
Professor Ravinder Dahiya, Bendable Electronics and Sensing Technologies Research Group, James Watt School of Engineering, University of Glasgow
Professor Dahiya added, “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.”
Professor Dahiya also stated, “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.”
Printed GaAs Microstructures based Flexible High-Performance Broadband Photodetectors
Printed GaAs Microstructures based Flexible High-Performance Broadband Photodetectors. Video Credit: University of Glasgow.
Ayoub Zumeit and Abhishek Dahiya from the BEST group, co-authors of the study, explained, “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.”
The Engineering and Physical Sciences Research Council (EPSRC) provided funding for the study.
Zumeit, A., et al. (2022) Printed GaAs Microstructures-Based Flexible High-Performance Broadband Photodetectors. Advanced Materials Technologies. doi.org/10.1002/admt.202200772.