An efficient and stable tin-based perovskite solar cell passivated by aminoguanidine hydrochloride

Abstract

It is challenging to fabricate a simultaneously high-performance and stable Sn-based perovskite device owing to the inferiority of the Sn-based perovskite film and the rapid oxidation of Sn²⁺. Herein, a simple approach was employed and involved introducing an additive of aminoguanidine hydrochloride (NH₂GACl) into a perovskite precursor solution to prepare efficient Sn-based perovskite solar cells. A higher film quality was obtained, due to the formation of strong hydrogen bonding between halide ions in the perovskite and NH₂GACl, which helped to passivate the defects and lessen the rate of Sn²⁺ oxidation. Also, the addition of NH₂GACl was indicated to effectively adjust the energy level alignment between Sn-based perovskite and the adjacent layer, with this adjustment facilitating the charge transport. The perovskite device modified with NH₂GACl achieved a power conversion efficiency of up to 7.3%, and retained 90% of its initial efficiency after 30 days in a nitrogen glovebox without being encapsulated.