The most recent discovery published in Nature Physics and made by researchers at the Institute of Photonic Science (ICFO), in collaboration with Massachusetts Institute of Technology, USA, Max Planck Institute for Polymer Research, Germany, and Graphenea S.L., Spain, demonstrate that graphene is able to convert a single photon that it absorbs into multiple electrons that could drive electric current (excited electrons) - a very promising discovery that makes graphene an important alternative material for light detection and harvesting technologies, now based on conventional semiconductors like silicon.
The experiments show that high energy photons (e.g. violet) are converted into a larger number of excited electrons than low energy photons (e.g. infrared). The observed relation between the photon energy and the number of generated excited electrons shows that graphene converts light into electricity with very high efficiency. Although there are some issues for direct applications, such as graphene's low absorption, graphene holds the potential to cause radical changes in many technologies that are currently based on conventional semiconductors.