Stabilization of formamidinium lead triiodide α-phase with isopropylammonium chloride for perovskite solar cells

April 29, 2021

Title

Stabilization of formamidinium lead triiodide α-phase with isopropylammonium chloride for perovskite solar cells

Author

Byung-wook Park, Hyoung Woo Kwon, Yonghui Lee, Do Yoon Lee, Min Gyu Kim, Geonhwa Kim, Ki-jeong Kim, Young Ki Kim, Jino Im, Tae Joo Shin, Sang Il Seok

Year

2021

Journal

Nature Energy

Abstract

Formamidinium lead triiodide (FAPbI3) perovskite solar cells (PSCs) are mainly fabricated by sequentially coating lead iodide and formamidinium iodide, or by coating a solution in which all components are dissolved in one solvent (one-pot process). The PSCs produced by both processes exhibited similar efficiencies; however, their long-term stabilities were notably different. We concluded that the major reason for this behaviour is the stabilization of the α-FAPbI3 phase by isopropylammonium cations produced by the chemical reaction between isopropyl alcohol, used as solvent, and methylammonium chloride, added during the process. On this basis, we fabricated PSCs by adding isopropylammonium chloride to the perovskite precursor solution for the one-pot process and achieved a certified power conversion efficiency of 23.9%. Long-term operational current density–voltage measurements (one sweep every 84 min under 1-Sun irradiation in nitrogen atmosphere) showed that the as-fabricated device with an initial efficiency of approximately 20% recorded an efficiency of about 23% after 1,000 h that gradually degraded to about 22% after an additional 1,000 h.

Instrument

FTIR-6800

Keywords

FTIR spectroscopy, isopropylammonium chloride, solar cells, perovskite