Probing the ionic defect landscape in halide perovskite solar cells

Point defects in metal halide perovskites play a critical role in determining their properties and optoelectronic performance; however, many open questions remain unanswered. In this work, we apply impedance spectroscopy and deep-level transient spectroscopy to characterize the ionic defect landscap...

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Bibliographic Details
Published in:Nature communications 2020-11, Vol.11 (1), p.6098-6098, Article 6098
Main Authors: Reichert, Sebastian, An, Qingzhi, Woo, Young-Won, Walsh, Aron, Vaynzof, Yana, Deibel, Carsten
Format: Article
Language:English
Subjects:
639/301/119
639/624/1075/524
Anions
Cations
Deep level transient spectroscopy
Humanities and Social Sciences
Metal halides
multidisciplinary
Open circuit voltage
Optoelectronic devices
Perovskites
Photovoltaic cells
Point defects
Precursors
Science
Science (multidisciplinary)
Solar cells
Spectroscopy
Spectrum analysis
Stoichiometry
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Summary:Point defects in metal halide perovskites play a critical role in determining their properties and optoelectronic performance; however, many open questions remain unanswered. In this work, we apply impedance spectroscopy and deep-level transient spectroscopy to characterize the ionic defect landscape in methylammonium lead triiodide (MAPbI 3 ) perovskites in which defects were purposely introduced by fractionally changing the precursor stoichiometry. Our results highlight the profound influence of defects on the electronic landscape, exemplified by their impact on the device built-in potential, and consequently, the open-circuit voltage. Even low ion densities can have an impact on the electronic landscape when both cations and anions are considered as mobile. Moreover, we find that all measured ionic defects fulfil the Meyer–Neldel rule with a characteristic energy connected to the underlying ion hopping process. These findings support a general categorization of defects in halide perovskite compounds. Defects in perovskite affect the properties and performance in optoelectronic devices, yet the nature of ionic defects remains elusive. Here, the authors investigate the ionic defect landscape in perovskite introduced by varying precursor stoichiometry, and find the defects fulfill the Meyer-Neldel rule.
ISSN:2041-1723
2041-1723
DOI:10.1038/s41467-020-19769-8