Designing Carrier Selective Perovskite on Silicon 3T Tandems

Abstract : We explore design criteria for a new multijunction solar cell concept, the three terminal selective band offset barrier solar cell (3T-SBOB). The 3T-SBOB reaches tandem solar efficiencies without suffering from series current constraints of two terminal designs, and without suffering from grid alignement issues of four terminal designs. It consists of a low bandgap silicon interdigitated back contact solar cell, connected to a high bandgap top cell by a selective band offset barrier (SBOB). The SBOB allows transport of only one type of charge carrier, leading to independent quasi-Fermi level separations in top and bottom cells under illumination It reaches tandem efficiencies with three terminals and with technical advantages over 2T and 4T devices. This paper reports results of the design of the 3T-SBOB device. Two candidate materials for this critical ETL and SBOB material are SnO2 and PC(71)BM. This paper presents these preliminary materials studies and resulting device structures which will be evaluated in a forthcoming H2020 Solar-ERANET project (BOBTANDEM) the kick-off of which coincides with this conference.