Substoichiometric Mixing of Metal Halide Powders and Their Single-Source Evaporation for Perovskite Photovoltaics
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Author
Guesnay, Quentin
McMonagle, Charles J.
Chernyshov, Dmitri
Zia, Waqas
Wieczorek, Alexander
Siol, Sebastian
Saliba, Michael
Ballif, Christophe
Wolff, Christian M.
Abstract
High-vacuum, single-source thermal evaporation is an appealing deposition process for perovskite photovoltaics. It promises the homogeneous and precisely controlled growth of very pure and homogeneous films on large areas in a conformal way. In this work, we study mechanically synthesized substoichiometric cesium bromide-lead iodide precursors, the single-source evaporation of the resulting mixes, subsequent deposited metal halide thin films, and converted perovskite thin films. Diffraction pattern analysis reveals the absence of new phases formed during ball-milling. Using synchrotron in situ grazing-incidence wide-angle X-ray scattering and energy-dispersive X-ray spectroscopy, we demonstrate that halide exchange between precursors occurs during the evaporation process. It is also found that a higher cesium bromide content results in films with more impurities. The proof-of-concept photovoltaic devices with the optimized cesium bromide content reach an efficiency of 15% for an optical bandgap of 1.7 eV. © 2023 American Chemical Society.
Publication Reference
ACS Photonics Volume 10, Issue 9, Pages 3087 - 3094
Year
2023-09-20