Issue 8, 2023

Quantifying electrochemical losses in perovskite solar cells

Abstract

We quantify electrochemical losses in perovskite solar cells (PSCs) based on methylammonium lead triiodide (MAPbI3) films with impedance analysis. We focus on the characteristic signatures of impedance spectra taken from PSCs, in particular the negative capacitance hook widely observed in the low frequency regime. We elucidate the underlying physical origin for the negative capacitance by applying a generalized equivalent circuit model (ECM) for PSCs that accounts for fast electrical dynamics resulting in high frequency (HF) signatures due to electronic processes, and much slower electrochemical dynamics that result in low frequency (LF) signatures in the spectra. We observe relaxation times faster than 10−6 s in the HF regime that can be attributed to electrical dynamics, while relaxation times longer than 10−3 s in the LF regime that are consistent with electrochemical dynamics. The voltage-dependence and timescales of the electrochemical dynamics are consistent with MA+ and I migration in the MAPbI3 absorber layer. At higher applied voltages, we observe a highly non-linear response from the PSC which is consistent with irreversible chemical changes in the MAPbI3 absorber. We demonstrate how ECM modelling combined with the analysis of ECM fit quality is a useful approach for in situ monitoring and quantitative diagnosis of loss mechanisms in PSC.

Graphical abstract: Quantifying electrochemical losses in perovskite solar cells

Supplementary files

Article information

Article type
Paper
Submitted
18 Aug 2022
Accepted
31 Jan 2023
First published
31 Jan 2023
This article is Open Access
Creative Commons BY license

J. Mater. Chem. C, 2023,11, 2911-2920

Quantifying electrochemical losses in perovskite solar cells

Tulus, J. Wang, Y. Galagan and E. von Hauff, J. Mater. Chem. C, 2023, 11, 2911 DOI: 10.1039/D2TC03486G

This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. You can use material from this article in other publications without requesting further permissions from the RSC, provided that the correct acknowledgement is given.

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