Improving Solar Cell Efficiency of Silicon and Silicon Tandem Structure by Using Surface Modification

Silicon heterojunction (SHJ) solar cells face challenges in maximizing energy capture due to limitations in light collection and surface passivation. To address this, the use of SHJ tandem solar cells in a back-to-back configuration is explored, allowing illumination from both sides to enhance light absorption and energy generation. This study aims to improve the stability and efficiency of these cells through Al₂O₃ and Nafion surface treatments. Al₂O₃ is deposited to enhance bifacial light collection, while Nafion is applied for surface passivation to increase the fill factor (FF). The method involves adding 0.1–0.6 units of incident light to the rear of the cells to evaluate the effects of these treatments. The results show a 2.06% increase in efficiency with Al₂O₃ and a 1.72% improvement with Nafion under standard illumination conditions. The optimized tandem SHJ with Al₂O₃ and Nafion achieves a J_sc of 62.01 mA cm⁻², V_oc of 650.63 mV, FF of 76.49%, and an efficiency of 30.86%. These findings demonstrate the significant potential of these surface treatments to enhance the overall performance of bifacial back-to-back tandem SHJ solar cells.