Metastable Oxygen-Induced Light-Enhanced Doping in Mixed Sn–Pb Halide Perovskites

• DOI: 10.1021/jacs.4c08924
• Publication Date: 2024-11-04T13:51:37Z
• Authors: Jasmeen Nespoli; Matthijs Mugge; Lara M. van der Poll; Snigdha Lal; Bahiya Ibrahim; Bart Boshuizen; Valentina M. Caselli; Arjan J. Houtepen; Lars J. Bannenberg; Tom J. Savenije
• Keywords: Metastability

Mixed Sn–Pb halide perovskites are promising absorber materials for solar cells due to the possibility of tuning bandgap energy down 1.2–1.3 eV. However, tin-containing susceptible oxidation affecting optoelectronic properties. In this work, we investigated qualitatively and quantitatively metastable oxygen-induced doping in isolated ASnxPb1–xI3 (where A is methylammonium or a mixture formamidinium cesium) perovskite thin films by means microwave conductivity, structural optical characterization techniques. We observe that longer oxygen exposure times lead progressively higher dark conductivities, which slowly decay back their original levels over days. Here acts as an electron acceptor, leading tin from Sn2+ Sn4+ creation free holes. The enhanced exposing simultaneously light. Next, show not only leads reduction photoconductivity signal but also induces long-term effects even after loss doping, thought derive consecutive reactions formation defect states. On prolonged light, changes can be observed related SnOx iodide near surface. Our work highlights short-term immediately impairs charge carrier dynamics perovskite, while degradation noticeable upon accumulation products. Hence, efficient cells, mixed during production operation should rigorously blocked.