Issue 2, 2024

Substitution of lead with tin suppresses ionic transport in halide perovskite optoelectronics

Abstract

Despite the rapid rise in the performance of a variety of perovskite optoelectronic devices with vertical charge transport, the effects of ion migration remain a common and longstanding Achilles’ heel limiting the long-term operational stability of lead halide perovskite devices. However, there is still limited understanding of the impact of tin (Sn) substitution on the ion dynamics of lead (Pb) halide perovskites. Here, we employ scan-rate-dependent current–voltage measurements on Pb and mixed Pb–Sn perovskite solar cells to show that short circuit current losses at lower scan rates, which can be traced to the presence of mobile ions, are present in both kinds of perovskites. To understand the kinetics of ion migration, we carry out scan-rate-dependent hysteresis analyses and temperature-dependent impedance spectroscopy measurements, which demonstrate suppressed ion migration in Pb–Sn devices compared to their Pb-only analogues. By linking these experimental observations to first-principles calculations on mixed Pb–Sn perovskites, we reveal the key role played by Sn vacancies in increasing the iodide ion migration barrier due to local structural distortions. These results highlight the beneficial effect of Sn substitution in mitigating undesirable ion migration in halide perovskites, with potential implications for future device development.

Graphical abstract: Substitution of lead with tin suppresses ionic transport in halide perovskite optoelectronics

Supplementary files

Article information

Article type
Paper
Submitted
04 Nov. 2023
Accepted
23 Nov. 2023
First published
27 Nov. 2023
This article is Open Access
Creative Commons BY license

Energy Environ. Sci., 2024,17, 760-769

Substitution of lead with tin suppresses ionic transport in halide perovskite optoelectronics

K. Dey, D. Ghosh, M. Pilot, S. R. Pering, B. Roose, P. Deswal, S. P. Senanayak, P. J. Cameron, M. S. Islam and S. D. Stranks, Energy Environ. Sci., 2024, 17, 760 DOI: 10.1039/D3EE03772J

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