Efficient bifacial Cu2ZnSnSe4 solar cells

In this work, the concept of bifacial solar cells is experimentally demonstrated for the first time for pure-selenium kesterite using several transparent back contacts (TBC). This opens the way to new possible applications for kesterite based thin films solar cells like building integration and/or multi-junction devices for better solar spectrum utilization. The absorbers were produced by using a two step synthesis process (sputtering + reactive annealing) onto transparent conductive oxides. Devices with power conversion efficiencies ranging from 1.8% to 3.3% are here presented.