Event Details
Solvent Esterification and Stoichiometric Control in Ambient-Grown FAPbI3 Single-Crystal Solar Cells
Presenter: Parinaz Moazzezi
Supervisor:
Date: Wed, August 12, 2026
Time: 16:00:00 - 00:00:00
Place: Elliot Building, Room 230
ABSTRACT
Abstract:
Inverse temperature crystallization (ITC) is a widely used technique for growing high-quality perovskite single crystals; however, the chemical evolution of precursor solutions during prolonged crystal growth remains poorly understood. This seminar presents our recent discovery of a previously overlooked solvent–precursor interaction that governs the stability of formamidinium lead iodide (FAPbI3) single crystals grown in ambient air. We demonstrate that FAPbI3 promotes an esterification reaction between γ-butyrolactone (GBL) and 2-methoxyethanol (2ME), resulting in crystal redissolution and reduced phase stability during extended heating. By introducing a slight PbI2 deficiency in the precursor solution, this degradation pathway is suppressed, enabling stable growth of phase-pure α-FAPbI3 single crystals with reduced defect density and improved optoelectronic properties. The resulting single-crystal solar cells achieve a power conversion efficiency of 22.99%, representing a record for ambient-air-fabricated FAPbI3 single-crystal solar cells. This work provides new mechanistic insights into inverse temperature crystallization and establishes precursor stoichiometry control as an effective strategy for producing high-performance perovskite single-crystal photovoltaic devices.