Sandwiching an oxygen-rich layer of silicon between a solar cell and its metal contact has allowed researchers in Europe to break performance records for the efficiency with which silicon solar cells convert sunlight into electricity. But the challenge now is how to make these so-called passivating contacts suitable for mass production.‘There is currently a lot of excitement about passivating contacts among the solar cell community,’ said Dr Byungsul Min at the Institute for Solar Energy Research in Hamelin (ISFH), Germany.