Interfacial Engineering of Cu<sub>2</sub>O Passivating Contact for Efficient Crystalline Silicon Solar Cells with an Al<sub>2</sub>O<sub>3</sub> Passivation Layer
Le Li, Guanlin Du, Xi Zhou, Yinyue Lin, Yuanwei Jiang, Xingyu Gao, Linfeng Lu, Gang Li, Wei Zhang, Qiang Feng, Jilei Wang, Liyou Yang, Dongdong Li
Abstract
Passivating contacts that simultaneously promote carrier selectivity and suppress surface recombination are considered as a promising trend in the crystalline silicon (c-Si) photovoltaic industry. In this work, efficient p-type c-Si (p-Si) solar cells with cuprous oxide (Cu2O) hole-selective contacts are demonstrated. The direct p-Si/Cu2O contact leads to a substoichiometric SiOx interlayer and diffusion of Cu into the silicon substrate, which would generate a deep-level impurity behaving as carrier recombination centers. An Al2O3 layer is subsequently employed at the p-Si/Cu2O interface, which not only serves as a passivating and tunneling layer but also suppresses the redox reaction and Cu diffusion at the Si/Cu2O interface. In conjunction with the high work function of Au and the superior optical property of Ag, a power conversion efficiency up to 19.71% is achieved with a p-Si/Al2O3/Cu2O/Au/Ag rear contact. This work provides a strategy for reducing interfacial defects and lowering energy barrier height in passivating contact solar cells.