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 Nov. 2022
Accepted
14 Febr. 2023
First published
22 Febr. 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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