Bifunctional Organic Spacers for Formamidinium-Based Hybrid Dion-Jacobson Two-Dimensional Perovskite Solar Cells.

Li, Yang; Milić, Jovana V; Ummadisingu, Amita; Seo, Ji-Youn; Im, Jeong-Hyeok; Kim, Hui-Seo; Liu, Yuhang; Dar, M Ibrahim et al. · Nano Lett · 2019

basic_science · Level V

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Abstract

Three-dimensional (3D) perovskite materials display remarkable potential in photovoltaics owing to their superior solar-to-electric power conversion efficiency, with current efforts focused on improving stability. Two-dimensional (2D) perovskite analogues feature greater stability toward environmental factors, such as moisture, owing to a hydrophobic organic cation that acts as a spacer between the inorganic layers, which offers a significant advantage over their comparatively less stable 3D analogues. Here, we demonstrate the first example of a formamidinium (FA) containing Dion-Jacobson 2D perovskite material characterized by the BFA <sub>n-1</sub>Pb <sub>n</sub>I<sub>3 n+1</sub> formulation through employing a novel bifunctional organic spacer (B), namely 1,4-phenylenedimethanammonium (PDMA). We achieve remarkable efficiencies exceeding 7% for (PDMA)FA<sub>2</sub>Pb<sub>3</sub>I<sub>10</sub> based 2D perovskite solar cells resisting degradation when exposed to humid ambient air, which opens up new avenues in the design of stable perovskite materials.