The Chemistry of the Passivation Mechanism of Perovskite Films with Ionic Liquids

Shunlin Zhang; Tianyu Xiao; Farzaneh Fadaei Tirani; Rosario Scopelliti; Mohammad Khaja Nazeeruddin; Dunru Zhu; Paul J Dyson; Zhaofu Fei

doi:10.1021/acs.inorgchem.1c03862

The Chemistry of the Passivation Mechanism of Perovskite Films with Ionic Liquids

Inorg Chem. 2022 Mar 28;61(12):5010-5016. doi: 10.1021/acs.inorgchem.1c03862. Epub 2022 Mar 15.

Authors

Shunlin Zhang^{1

2}, Tianyu Xiao¹, Farzaneh Fadaei Tirani², Rosario Scopelliti², Mohammad Khaja Nazeeruddin², Dunru Zhu¹, Paul J Dyson², Zhaofu Fei²

Affiliations

¹ College of Chemical Engineering, State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing 211816, China.
² Institut des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland.

PMID: 35290056
DOI: 10.1021/acs.inorgchem.1c03862

Abstract

Passivation of perovskite films by ionic liquids (ILs) improves the performance (efficiency and stability) of perovskite solar cells (PSCs). However, the role of ILs in the passivation of perovskite films is not fully understood. Here, we report the reactions of commonly used ILs with the components of perovskites. The reaction of ILs with perovskite precursors (PbI₂ and methylammonium iodide or formamidinium iodide) in a 1:1:1 molar ratio affords one-dimensional (1D) salts composed of the IL cation interspersed along infinite 1D polymeric [PbI₃]^-_n chains. If the IL is applied in excess, the resulting crystal is composed of six cations surrounding a discrete [Pb₃I₁₂]^6- cluster. All the isolated salts were unambiguously characterized by single-crystal X-ray diffraction analysis, which also reveals extensive hydrogen-bonding interactions.