Progress in passivating selective contacts for heterojunction silicon solar cells

Photovoltaic (PV) technology, particularly silicon solar cells (SSCs), has emerged as a key player in meeting this demand due to its mature technology, prolonged stability, non-toxicity, and material abundance. Heterojunction (HJT) solar cells have shown significant promise by eliminating dopant-diffusion processes and separating c-Si wafers from metal contacts. In recent years, the notable enhancement in the record PCE of SSCs primarily hinges on advancements in HJT technology, incorporating sophisticated passivating selective contacts. This review explores the evolution and recent progress of passivating selective contacts in HJT solar cells, examining doped silicon-based materials, metal compounds, and organic materials. Despite dopant-free contacts still lagging in efficiency, their potential for high fill factor (FF) values suggests viable pathways for future research. This study aims to provide a comprehensive overview, highlighting key advancements, challenges, and prospects in the ongoing development of HJT technology for higher performance, enhanced stability, and reduced costs.