Crystalline silicon solar cells with thin poly‐SiO x carrier‐selective passivating contacts for perovskite/c‐Si tandem applications

Single junction crystalline silicon (c‐Si) solar cells are reaching their practical efficiency limit whereas perovskite/c‐Si tandem solar cells have achieved efficiencies above the theoretical limit of single junction c‐Si solar cells. Next to low‐thermal budget silicon heterojunction architecture, high‐thermal budget carrier‐selective passivating contacts (CSPCs) based on polycrystalline‐SiO x (poly‐SiO x ) also constitute a promising architecture for high efficiency perovskite/c‐Si tandem solar cells. In this work, we present the development of c‐Si bottom cells based on high temperature poly‐SiO x CSPCs and demonstrate novel high efficiency four‐terminal (4T) and two‐terminal (2T) perovskite/c‐Si tandem solar cells. First, we tuned the ultra‐thin, thermally grown SiO x . Then we optimized the passivation properties of p‐type and n‐type doped poly‐SiO x CSPCs. Here, we have optimized the p‐type doped poly‐SiO x CSPC on textured interfaces via a two‐step annealing process. Finally, we integrated such bottom solar cells in both 4T and 2T tandems, achieving 28.1% and 23.2% conversion efficiency, respectively.