In a surprising twist, researchers from Aalto University have recently developed a black silicon photodetector that has reached above 130% external quantum efficiency, sending the research team into a brief state of disbelief.
An external quantum efficiency of more than 100% means that one incoming photon generates more than one electron to the external circuit – a phenomenon that hasn’t been observed up until now since the presence of electrical and optical losses has reduced the number of collected electrons.
The research team believes their photodetector is the first single photovoltaic device to break past the 100% external quantum efficiency threshold at UV, which could eventually lead to efficiencies beyond the Shockley-Queisser limit.
“When we saw the results, we could hardly believe our eyes. Straight away we wanted to verify the results by independent measurements,” said Professor Hele Savin, Head of the Electron Physics research group at Aalto University.
For that, the researchers turned to the German National Metrology Institute, or the Physikalisch-Technische Bundesanstalt (PTB), known for providing the most accurate and