Patterning Design for Edge Passivation in Compound Crystalline Silicon Solar Cells

Compound crystalline silicon (c–Si) solar cells demonstrate unparalleled advantages in carrier–selective contact engineering while enabling eco–friendly and cost–effective fabrication compared to conventional doped devices. Despite these inherent strengths, their efficiency suffers from severe degradation due to edge recombination at wafer peripheries. In order to address this fundamental challenge, a breakthrough edge engineering strategy is developed through innovative patterning design. By implementing a non–active buffer zone between the active region and wafer edge, unprecedented suppression of carrier recombination at c–Si edge defects is achieved, demonstrating a sixfold enhancement in Shockley–Read–Hall lifetime ( τ SRH ) from 2.32 to 13.28 ms, and a 4.45% absolute improvement in pseudo fill factor (pFF). The optimized devices delivered record–breaking performance, with 84.62% fill factor (FF) and 746 mV open–circuit voltage ( V OC ). When synergized with enhanced light–trapping capability confirmed by theoretical simulations, the design achieved 38.50 mA cm −2 short–circuit current density ( J SC ) and 24.31% efficiency. The latter is the highest reported value for c–Si solar cells employing MoO X as a hole transport layer (HTL). This study established a transformative methodology that overcomes edge recombination limitations through simple yet effective spatial defect engineering, providing critical design principles for both compound c –Si solar cells and other c–Si photovoltaics.