Issue 11, 2023

Single-particle optical study on the effect of chloride post-treatment of MAPbI3 nano/microcrystals

Abstract

Surface passivation by post-treatment with methylammonium chloride (MACl) is regarded as a promising strategy to suppress surface defects in organic–inorganic lead halide perovskites and elevate the efficiency of solar cells based on these materials. However, traditional MACl post-treatment methods often impede the performance of the final device, due to the creation of additional unwanted defects. Herein, we report a novel approach for chloride post-treatment by applying a mixed ethanol/toluene solvent and validate its beneficial effect on the structure, composition, and optical properties of methylammonium lead iodide nano/microcrystals and related photosensitive devices. An optimized (mild) Cl content improves the crystallinity, enhances photoluminescence (PL) intensity, provides longer PL lifetimes, and induces brighter and longer ON-states in single-particle emission trajectories. On top of a reduction in the population percentage of crystals showing gradual photodegradation, our Cl-treatment method even leads to photobrightening. Additionally, the extent of carrier communication throughout spatially distant nanodomains enhances after MACl-based post-modification. Our results demonstrate that surface-bound Cl significantly reduces the trap density induced by under-coordinated lead ions or iodide vacancies and reveal the importance of a careful consideration of the applied Cl content to avoid the generation of high-bandgap MAPbCl3 heterojunctions upon excessive Cl treatment. Importantly, significant trap passivation upon MACl treatment translates into a more stable and elevated photocurrent in the corresponding photodetector device. We anticipate these findings will be beneficial for designing durable, high-performance lead halide perovskite photonic devices.

Graphical abstract: Single-particle optical study on the effect of chloride post-treatment of MAPbI3 nano/microcrystals

Supplementary files

Article information

Article type
Paper
Submitted
16 11 2022
Accepted
14 2 2023
First published
22 2 2023
This article is Open Access
Creative Commons BY license

Nanoscale, 2023,15, 5437-5447

Single-particle optical study on the effect of chloride post-treatment of MAPbI3 nano/microcrystals

H. Jin, A. Mukherjee, L. Chouhan, J. A. Steele, F. de Jong, Y. Gao, M. B. J. Roeffaers, J. Hofkens and E. Debroye, Nanoscale, 2023, 15, 5437 DOI: 10.1039/D2NR06427H

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