High-efficiency hybrid solar cell with a nano-crystalline silicon oxide layer as an electron-selective contact

Highlights: • For efficient silicon solar cells, this study introduces a novel hybrid solar cell. • Two passivating-contact structures were Incorporated in the hybrid solar cell. • 6 and 30 nm of a-Si:H(i) and nc-SiO_x(n) yielded the best solar cell results. • Maximum performance V_oc = 724 mV, Jsc = 38.95 mA/cm², FF = 75.9%, η = 21.4% was achieved. • Provide a foundation for future advancements in c-Si solar cell's performance. The efficiency of silicon heterojunction solar cells is limited by various factors including low surface passivation, parasitic absorption, and recombination losses. Herein, the surface passivation quality of crystalline silicon solar cells is improved by a hybrid passivation structure including a silicon heterojunction contact at the front side and a stack of tunneling oxide with n-type nano-crystalline silicon oxide (nc-SiO_x(n)) passivating contact at the rear side. A passivation contact with thin silicon oxide (SiO₂) and poly-silicon was previously proposed to enhance the rear surface passivation. In our study, the poly-silicon layer is swapped with the nc-SiO_x(n) layer to improve the effective surface passivation, electrical properties, recombination losses, and carrier selectivity. The hybrid passivation structure shows significant passivation improvement with lifetime (τ_eff) of 2696 μs and implied open-circuit voltage (i-V_oc) of 735 mV as compared with both-sides traditional silicon heterojunction (1650 μs, 719 mV) and tunneling passivation contact (2146 μs, 725 mV). The hybrid solar cell shows a potential performance as; open circuit voltage (V_oc) = 724 mV, short circuit current (J_sc) = 38.95 mA/cm², fill factor (FF) of 75.9%, efficiency (η) = 21.4%. However, there is room to further improve the overall cell performance.