The stabilization of ?-phase Formamidinium lead triiodide perovskite solar cell with thiocyanate substitution

Abstract

Currently the organic-inorganic hybrid perovskite solar cells (PSCs) have achieved high efficiency over 25% However the instability of perovskite is still a concerned for practical application of PSCs under ambient condition Although formamidinium lead triiodide (FAPbI3) perovskite exhibits ideal bandgap of 1 47 eV which is close to the Shockley-Queisser limit the perovskite phase of FAPbI3 (?-phase FAPbI3) easily converts into non-perovskite phase (δ-phase FAPbI3) at room temperature whose optoelectronic properties are not suitable for solar cells The purpose of this study is to introduce two additives methylammonium chloride (MACl) and formamidinium thiocyanate (FASCN) in FAPbI3 perovskite to stabilize the ?-phase FAPbI3 in virtue of composition engineering Addition of MACl can relax strain of FAPbI3 perovskite lattice structure while pseudo-halide (such as SCN) can stabilize the perovskite lattice structure as well The results indicate that the halide of Cl and pseudo-halide of SCN from the additive show competitive relationship in the resultant perovskite film and different mechanism to improve the stability of FAPbI3 perovskite

Date of Award	2020
Original language	English
Supervisor	Chao-Yu Chen (Supervisor)