Black silicon photodetector achieves record efficiency of above 130%

The efficiency was so high that at first the researchers had a hard time believing the result. Now Aalto University spin-off company ElFys Inc. already supplies the record detectors for several industry sectors.

Aalto University researchers have developed a black silicon photodetector that has reached above 130% efficiency. Thus, for the first time, a single photovoltaic device has exceeded the 100% external quantum efficiency limit at UV. This result opens new avenues for improving efficiencies beyond the famous 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,” says Prof. Hele Savin, head of the Electron Physics research group at Aalto University.  

The independent measurements were carried out by the German National Metrology Institute, Physikalisch-Technische Bundesanstalt (PTB), which is known to provide the most accurate and reliable measurement services in Europe.

Head of the PTB Laboratory of Detector Radiometry, Dr. Lutz Werner comments, “After seeing the results, I instantly realized that this is a significant breakthrough — and at the same time, a much-welcomed step forward for us metrologists dreaming of higher sensitivities.”

The secret behind the breakthrough: Unique nanostructures

The external quantum efficiency of a device is 100% when one incoming DOI: 10.1103/PhysRevLett.125.117702