NiOx/MoOx bilayer as an efficient hole-selective contact in crystalline silicon solar cells
Le Li, Guanlin Du, Yinyue Lin, Xi Zhou, Zeyu Gu, Linfeng Lu, Wenzhu Liu, Jin Huang, Jilei Wang, Liyou Yang, Shan‐Ting Zhang, Dongdong Li
Abstract
Designing effective carrier-selective contact is a prerequisite for high-efficiency crystalline silicon (c-Si) solar cells. Compared to doped silicon thin films, wide-band-gap transition metal oxides (TMOs) feature low parasitic absorption, but their carrier selectivity and passivation being poor leads to a mediocre cell efficiency. Herein, we introduce a NiOx/MoOx bilayer as an efficient hole-selective contact in c-Si solar cells. A power conversion efficiency (PCE) of 21.31% is achieved using NiOx/MoOx bilayer, outperforming cells with a single layer of NiOx or MoOx. Upon depositing NiOx on MoOx, interfacial reactions modify the stoichiometry and defect chemistry in both oxides, leading to a band alignment beneficial for hole selectivity. By inserting a SiOx tunneling layer on c-Si surface to further suppress recombination, we achieve a PCE of 21.60% (fill factor 83.34%). Our work highlights a promising approach to improve the performance of dopant-free c-Si solar cells by employing cost-effective TMOs as hole-selective contact.