Imaging Spatial Variations of Optical Bandgaps in Perovskite Solar Cells
Date
2019-02-14
Authors
Chen, Boyi
Peng, Jun
Shen, Heping
Duong, The
Walter, Daniel
Johnston, Steve
AlāJassim, Mowafak M.
Weber, Klaus
White, Thomas
Catchpole, Kylie
Journal Title
Journal ISSN
Volume Title
Publisher
Wiley
Abstract
A fast, nondestructive, camera-based method to capture optical bandgap images of perovskite solar cells (PSCs) with micrometer-scale spatial resolution is developed. This imaging technique utilizes well-defined and relatively symmetrical band-to-band luminescence spectra emitted from perovskite materials, whose spectral peak locations coincide with absorption thresholds and thus represent their optical bandgaps. The technique is employed to capture relative variations in optical bandgaps across various PSCs, and to resolve optical bandgap inhomogeneity within the same device due to material degradation and impurities. Degradation and impurities are found to both cause optical bandgap shifts inside the materials. The results are confirmed with micro-photoluminescence spectroscopy scans. The excellent agreement between the two techniques opens opportunities for this imaging concept to become a quantified, high spatial resolution, large-area characterization tool of PSCs. This development continues to strengthen the high value of luminescence imaging for the research and development of this photovoltaic technology.
Description
Keywords
bandgap, imaging, luminescence, perovskite, photovoltaic
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Source
Advanced Energy Materials
Type
Journal article
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Open Access
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Author Accepted Manuscript