A new form of flexible photodetector could provide future robots with an electronic skin capable of ‘seeing’ light beyond the range of human vision.
Researchers believe mechanical arms in light-sensitive manufacturing environments could become capable of detecting when conditions change, thanks to the new technology - Image via Adobestock
Engineers at Glasgow University announced their breakthrough development, involving a new method of printing microscale semiconductors made from gallium arsenide onto a flexible plastic surface.
According to the team, their material provides performance equivalent to the best conventional photodetectors on the market, and is capable of withstanding hundreds of cycles of bending and flexing.
In a paper published in Advanced Materials Technology, researchers outlined how they developed the technology, which allows the skin to detect light from a broad range of the electromagnetic spectrum.
It builds on previous research in which they developed a method of printing silicon circuitry directly onto the surface of flexible plastic, enabling the creation of high-performance bendable electronics.
Gallium arsenide is used in many electronic applications to create high-performance electronics. However, they have mainly been created on rigid surfaces – the Glasgow team are among the first to find a way to use gallium arsenide on a flexible substrate.
Researchers said they adapted their existing roll printing system to print gallium arsenide electronics onto a flexible surface using arrays of wires that are 15 micrometres in width. This allowed them to create a new type of flexible photodetector capable of sensing light from the ultraviolet range, through the visible portion of the spectrum, to the infrared – all of it requiring extremely low power.
The system is reportedly capable of ultrafast response to light, taking just 2.5 milliseconds to measure light and 8 milliseconds to recover.
To test the system’s durability, the team subjected it to rigorous testing in a machine designed to bend and twist it hundreds of times. Over the course of 500 cycles, they reported ‘no significant loss’ in the material’s performance.
Professor Ravinder Dahiya, of Glasgow University’s James Watt School of Engineering, is the leader of the Bendable Electronics and Sensing Technologies (BEST) research group which developed the skin.
“We’ve been working for a number of years now to advance the capabilities of flexible electronics,” Dahiya said. “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.”
Dahiya said the EPSRC-funded research could lend new abilities to future robots, such as in manufacturing, where mechanical arms in light-sensitive environments could become capable of detecting when conditions change and the safety or effectiveness of their work is 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,” Dahiya said.
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.”
