Converting light to electricity is one of the pillars of modern electronics, with the process essential for the operation of everything from solar cells and TV remote control receivers through to laser communications and astronomical telescopes. These devices rely on the swift and effective operation of this technology, especially in scientific equipment, to ensure the most efficient conversion rates possible. In this vein, researchers from the Institute of Photonic Sciences (Institut de Ciències Fotòniques/ICFO) in Barcelona have demonstrated a graphene-based photodetector they claim converts light into electricity in less than 50 quadrillionths of a second.
Graphene has already been identified as a superior substance for the transformation of photons to electrical current, even in the infrared part of the spectrum. However, prior to the ICFO research, it was unclear exactly how fast graphene would react when subjected to ultra-rapid bursts of light energy.
To test the speed of conversion, the ICFO team – in collaboration with scientists from MIT and the University of California, Riverside – utilized an arrangement consisting of graphene film layers set up as a p-n (positive-negative) junction semiconductor, a sub-50 femtosecond, titanium-sapphire, pulse-shaped laser to provide the ultrafast flashes of light, along with an ultra-sensitive pulse detector to capture the speed of conversion to electrical energy.