High Stability of Sn-Based Perovskite by Adding Reducing Agents for Perovskite Solar Cells

Tin-based (Sn) halide perovskites have become one of the most prospective photovoltaic materials due to their optoelectronic properties, high photoconversion efficiency and relatively low toxicity.[1][2] Nevertheless, the rapid crystallization of tin-based perovskite and the easy oxidation of Sn²⁺ to Sn⁴⁺ under ambient conditions increases the interest of the scientific community.[3] To avoid these undesirable processes, we will address by two different methods, for instance, (i) organic cations engineering in Sn-based halide perovskite microcrystals, and (ii) adding reducing agents in three dimensional perovskite thin film.<br/>On the one hand, Sn-based halide perovskite microcrystals have been synthetized by hot-injection method to control the dimensionality by changes the concentration of reactants. The physical properties suggest high photoluminescence quantum yield (PLQY) of 75% and 25% for chloride-based and bromide-based, respectively, and almost negligible for 2D Sn-based microcrystals.<br/>On the other hand, increasing the perovskite dimensionality, we suggest adding a variety of additives that act as reducing agents with different nature in thin film. The addition of these novel materials into the FASnI₃ (FA is formamidinium) perovskite solution controlled the oxidation reaction and improved the surface morphology. An inverted perovskite solar cell was prepared and characterized. Due to the Sn⁴⁺ concentration is reduced in the Sn-based perovskite layer, the power conversion efficiency in a solar cell and the cell stability under ambient conditions are improved notably in comparison with the pure FASnI₃.<br/><br/><b>References</b><br/>[1] Malekshahi Byranvand, M., Zuo W., Imani R., Pazoki M., Saliba M. (2022) ‘Tin-based halide perovskite materials: properties and applications’ Chemical Science, 13, 6766. DOI: 10.1039/d2sc01914k (Accepted 23^rd May 2022).<br/>[2] Li M., Li F., Gong J., Zhang T., Gao F., Zhang W.-H., Liu M. (2022) ‘Advances in Tin(II)-Based Perovskite Solar Cells: From Material Physics to Device Performance’ Advanced Science News, 3, 2100102. DOI: 10.1002/sstr.202100102 (Published online: 5^th October 2021).<br/>[3] Abdel-Shakour M., Chowdhury T. H., Matsuishi K., Bedja I., Moritomo Y., Islam A. (2021) ‘High-Efficiency Tin Halide Perovskite Solar Cells: The Chemistry of Tin (II) Compounds and Their Interaction with Lewis Base Additives during Perovskite Film Formation’ Solar RRL, 5, 2000606. DOI: 10.1002/solr.202000606 (Published online: 9^th December 2020).