Sulfur-enhanced surface passivation for hole-selective contacts in crystalline silicon solar cells
Yanhao Wang, Yirong Geng, Hongwei Hao, Wei Ren, Hai Feng Zhang, Jingjie Li, Yongzhe Zhang, Jilei Wang, Shaojuan Bao, Hui Wang, Shan‐Ting Zhang, Dongdong Li
Abstract
Effective surface passivation is pivotal for achieving high performance in crystalline silicon ( c -Si) solar cells. However, many passivation techniques in solar cells involve high temperatures and cost. Here, we report a low-cost and easy-to-implement sulfurization treatment as a surface passivation strategy. By treating p -type c -Si ( p -Si) wafers with (NH 4 ) 2 S solution, sulfur can be introduced onto the surface and passivate the dangling bonds by forming an Si–S bond. Sulfurization also contributes to a higher negative fixed charge at the p -Si/Al 2 O 3 interface and, thus, better field-effect passivation. Due to the improved passivation, sulfurization effectively enhances hole selectivity, evidenced by the substantially improved open-circuit voltage and efficiency of solar cells. Eventually, by employing sulfurization in hole-selective contacts, remarkable efficiencies of 19.85% and 22.01% are attained for NiO x - and MoO x -based passivating contact c -Si solar cells, respectively. Our work highlights a promising sulfurization strategy to enhance surface passivation and hole selectivity for dopant-free c -Si solar cells.