Progress, current challenges, and future opportunities for Sn-based perovskite solar cells: A comprehensive review

초록

Among the discoveries of eco-friendly perovskite solar cells (PSCs), Sn-based PSCs have achieved a competitive advantage due to their close-to-optimal bandgap, favorable electrical and optical properties, high absorption coefficient, and enhanced carrier mobilities. Sn-based perovskites are escalating the performance ladder for the provision of Pb-free alternatives that meet the challenges posed by greener environmental standards. Currently, Sn-based perovskite (PEA0.15FA0.85SnI3) and Sn-Pb mixed perovskite (Rb0.04Cs0.2FA0.76 Pb0.5Sn0.5I3) solar cells have achieved the power conversion efficiency (PCE) of 17.89 % and 24.13 %, respectively. However, Sn-based perovskite solar cells are still halfway in comparison with their Pb-based counterparts (27 %). To bridge the performance gap of Sn-based perovskite solar cells, there is a dire need to develop materials processing strategies that can guarantee overcoming their oxidative instability, rapid crystallization kinetics, and low defect tolerance. This review is aimed at highlighting the strategies adopted for the realization of highly efficient Sn-based photovoltaic devices through the formation of stable intermediate adducts and optimized crystallization kinetics between the solvent and the metal halide by employing a variety of solvents, antisolvents, and additive engineering approaches. Sn-based perovskites efficiency can be enhanced through the incorporation of bulky cations as spacer, and the role of defect physics has also been highlighted to combat the challenges for the pursuit of eco-friendly perovskites.

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