High‐performance hole‐selective V₂O_X/SiO_X/NiO_X contact for crystalline silicon solar cells

Abstract High work function vanadium oxide (V₂O_X, X < 5) is expected to induce strong upward band bending at crystalline silicon (c‐Si) surface thus selectively collect photogenerated hole‐carriers. However, the performance of c‐Si solar cells employing V₂O_X‐based hole‐selective contacts is still under expectation. Herein, we improve the hole‐selectivity of V₂O_X in combination with NiO_X. The innovative V₂O_X/NiO_X stack shows reduced contact resistivity but deteriorated minority carrier lifetime due to undesired interfacial reaction between V₂O_X and NiO_X. Inserting an ultrathin SiO_X interlayer suppresses the reaction and preserves the high work function of V₂O_X. A remarkable power conversion efficiency of 22.03% (fill factor of 83.07%) was achieved on p‐type c‐Si solar cells featuring a full‐area V₂O_X/SiO_X/NiO_X rear contact, which is so far the highest value reported for V₂O_X‐based selective contacts. Our work highlights the significance of implementing p‐type transition‐metal‐oxides to boost the selectivity of V₂O_X and the like.image