Real-Time Investigation of Sn(II) Oxidation in Pb-Free Halide Perovskites by X-ray Absorption and Mössbauer Spectroscopy
Date of Original Version
Sn(II) halide perovskites are a less toxic alternative to Pb-based materials in perovskite solar cells, but oxidation to Sn(IV) introduces additional degradation pathways. Improving stability requires mechanistic pictures of O2-and H2O-induced degradation and their synergy. We demonstrate that X-ray absorption spectroscopy reports the average valency of the bulk material, allowing oxidation kinetics to be measured from minutes to days. Optical and X-ray diffraction studies demonstrate the challenge of isolating oxidative degradation with techniques lacking element specificity and oxidation state sensitivity. Finally, 119Sn Mössbauer spectroscopy is presented as a lab-based technique capable of providing information on valency and speciation throughout oxidation.
Publication Title, e.g., Journal
ACS Applied Energy Materials
Smith, Melissa A., Min Chen, Zhenghong Dai, Cali Antolini, Gethmini K. Jayasekara, Srinivas K. Yadavalli, Benjamin J. Reinhart, Nitin P. Padture, and Dugan Hayes. "Real-Time Investigation of Sn(II) Oxidation in Pb-Free Halide Perovskites by X-ray Absorption and Mössbauer Spectroscopy." ACS Applied Energy Materials 4, 5 (2021). doi: 10.1021/acsaem.1c01143.