A new form of flexible photodetector could provide robots of the future with an electronic skin that can “see” light beyond human vision. A team of engineers at the University of Glasgow are behind a groundbreaking development involving a newly developed method for printing microscale semiconductors made of gallium arsenide onto a flexible plastic surface.

Its materials provide performance equivalent to the best conventional photodetectors on the market and can withstand hundreds of bending and twisting cycles. In a recent article published in the journal Advanced Material TechnologiesResearchers describe how they developed technology that enables skin to detect light over a broad electromagnetic spectrum.

Building on the team’s previous research, they developed a method for printing silicon circuits directly onto the surface of flexible plastic, allowing for highly efficient flexible electronics. Gallium arsenide is used to create high-performance electronics in many electronic applications. However, they were created mainly on solid substrates – the Glasgow team was one of the first to find a way to use gallium arsenide on a flexible substrate.

They adapted their existing roll-to-roll printing system to print gallium arsenide electronics on a flexible substrate using 15 micrometer-wide wire arrays. This allowed them to create a new type of flexible photodetector that could detect light from the ultraviolet range, from the visible part of the spectrum to the infrared, all of which required extremely low power.

The system is capable of ultra-fast light response, taking only 2.5 milliseconds to measure light and 8 milliseconds to recover; performance comparable to the best solid photodetectors currently available. To test the system’s durability, they subjected it to a series of rigorous tests on a machine designed to bend and twist the material hundreds of times. Over 500 cycles, the material showed no significant performance loss.

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

Professor Dahiya said: “For several years we have been working to expand the possibilities of flexible electronics. We’ve found new ways to print electronics directly onto flexible surfaces, created an electronic skin that can feel “pain,” and developed bendable electronics powered by the sun or human sweat.

“This latest development is the first time we have been able to print gallium arsenide onto flexible surfaces and opens up new avenues for our research.

“In the future, this type of photosensitive flexible material could provide new opportunities for robots. For example, mechanical arms used for manufacturing in light-sensitive environments will be able to sense when conditions change and the safety or efficiency of their operation is threatened. Flexible broad-spectrum photodetectors, the high data we tested It can find applications in a wide variety of wireless communication technologies where speeds and responsiveness will always be demanded.”

Ayub Zumeit and Abhishek Dahiya from the BEST group and co-authors of the paper added: “This could even be used to develop a human patch that will be used to monitor UV light exposure on sunny days and provide warnings when users are at risk of sunburn.” Source