Slow 'hot electrons' could improve solar cell efficiency

Photons with energy higher than the band gap of the semiconductor absorbing them give rise to what are known as hot electrons. The extra energy in respect to the band gap is lost very fast, as it is converted into heat and does not contribute to the voltage. University of Groningen Photophysics and Optoelectronics Professor Maria Antonietta Loi has now found a material in which these hot electrons retain their high energy levels for much longer. This might make it possible to use more of their e...