A team of engineers from the University of Glasgow have developed a new photodetector that could form the base for an electronic skin capable of detecting a broad range of the electromagnetic spectrum. The device was made by printing microscale gallium arsenide (GaAs) semiconductors onto a flexible plastic surface that can withstand hundreds of bending and flexing cycles.
GaAs is in many ways a wonderous material, capable of fast switching frequencies at low power and with low noise, suitable for many high-performance electronic devices. To date, however, such transistors have mainly been deposited on hard substrates, which is where the University of Glasgow team’s solution differs: The scientists printed GaAs electronics onto a flexible surface using arrays of wires that are 15 micrometres wide. The new type of flexible photodetector can sense light from the ultraviolet range, through the visible portion of the spectrum, to infrared – at extremely low power.
The system is capable of ultrafast responses, taking just 2.5ms to measure light and 8ms to recover – a performance as good as the best currently available non-flexible photodetectors.
“We’ve been working for many years to advance the capabilities of flexible electronics,” said Professor Ravinder Dahiya of the University of Glasgow’s James Watt School of Engineering, and leader of the Bendable Electronics and Sensing Technologies (BEST) research group. “We’ve found new ways to print electronics directly onto flexible surfaces, built electronic skin capable of feeling ‘pain’, and developed bendable electronics that can be powered by the sun or human sweat.”
The team believes this type of light-sensitive flexible material could give robots new abilities: mechanical arms used for manufacturing in light-sensitive environments could, for example, detect changing conditions and safety at work. Flexible, broad-spectrum photodetectors could also be used in wireless communication systems where fast transmission and response speeds are always in high demand.
“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 they are at risk of getting sunburnt,” said Dahiya.
