Effective Hydrogenation Strategies to Boost Efficiency over 20% for Crystalline Silicon Solar Cell with Al2O3/Cu2O Passivating Contact

• Published in: Advanced functional materials 2022-10, Vol.32 (43), p.n/a
• Main Authors: Li, Le, Ying, Lei, Lin, Yinyue, Li, Xiaodong, Zhou, Xi, Du, Guanlin, Gao, Yi, Liu, Wenzhu, Lu, Linfeng, Wang, Jilei, Yang, Liyou, Zhang, Shan‐Ting, Li, Dongdong
• Format: Article
• Language: English
• Subjects: Aluminum oxide; atomic layer deposition; Copper oxides; Crystal structure; crystalline silicon solar cells; Crystallinity; cuprous oxide; Density functional theory; Dopants; Heterojunctions; hole‐selective contacts; hydrogenated Al 2O 3; Hydrogenation; Interlayers; Materials science; Metal oxides; Passivity; Photovoltaic cells; Selectivity; Silicon; Solar cells; Transition metal oxides
• ISSN: 1616-301X; 1616-3028
• DOI: 10.1002/adfm.202207158

Passivation interlayers such as Al2O3 are required to improve the hole selectivity of dopant‐free passivating contact based on transition metal oxides. For the interlayer to provide low surface recombination as in conventional silicon heterojunctions (SHJs) or tunnel oxide passivated contact (TOPCon) technologies, “hydrogenation” strategies to effectively introduce hydrogen in passivation interlayers while being compatible with transition metal oxides (TMOs) are urgently sought after. In this work, an easy‐to‐implement strategy to successfully incorporate extra hydrogen in the Al2O3 passivation layer is developed. The chemical and field‐effect passivation mechanisms of the extra hydrogen are revealed via comprehensive experimental analyses and density functional theory calculations. By implementing H‐Al2O3 with Cu2O as the hole‐selective rear contact in p‐type crystalline silicon (c‐Si) solar cells, a remarkable efficiency of 20.35% is achieved (fill factor of 84.76%). The study highlights a promising approach to improve the passivation quality of dielectric interlayers and boost the performance of dopant‐free c‐Si solar cells to compete against mainstream c‐Si photovoltaics technologies. In exploring p‐type semiconductor Cu2O as a dopant‐free hole‐selective contact for crystalline Si solar cells, an ultra‐thin H‐Al2O3 prepared by atomic layer deposition utilizing a H2/N2 mixture as the carrier gas is adopted to improve the passivation quality. Finally, the device with a structure of p‐Si/H‐Al2O3/Cu2O/Pt/Ag dilivers a photoconversion efficiency of 20.35%.