Solvent Gaming Chemistry to Control the Quality of Halide Perovskite Thin Films for Photovoltaics

Research on solvent chemistry, particularly for halide perovskite intermediates, has been advancing the development of perovskite solar cells (PSCs) toward commercial applications. A predictive understanding of solvent effects on the perovskite formation is thus essential. This work systematically discloses the relationship among the basicity of solvents, solvent-contained intermediate structures, and intermediate-to-perovskite alpha-FAPbI(3) evolutions. Depending on their basicity, solvents exhibit their own favorite bonding selection with FA(+) or Pb2+ cations by forming either hydrogen bonds or coordination bonds, resulting in two different kinds of intermediate structures. While both intermediates can be evolved into alpha-FAPbI(3) below the delta-to-alpha thermodynamic temperature, the hydrogen-bond-favorable kind could form defect-less alpha-FAPbI(3) via sidestepping the break of strong coordination bonds. The disclosed solvent gaming mechanism guides the solvent selection for fabricating high-quality perovskite films and thus high-performance PSCs and modules.

Automated summary

This study systematically investigates the impact of solvents on perovskite solar cells (PSCs) and reveals the relationship between solvent basicity, solvent-contained intermediate structures, and intermediate-to-perovskite alpha-FAPbI(3) evolutions. It proposes a solvent gaming mechanism that guides the selection of solvents for fabricating high-quality perovskite films and achieving high-performance PSCs and modules.