Partial ligand exchange on CsPbI3 nanocrystals with alkyl phosphonium iodide improves phase stability and emission efficiency in light-emitting diodes
8 affiliations
- 1Nanochemistry, Istituto Italiano di Tecnologia Via Morego 30 16163 Genova Italy
- 2Department of Chemistry, Materials and Chemical Engineering, Politecnico di Milano Piazza Leonardo da Vinci 32 20133 Milano Italy
- 3Materials Characterization Facility, Istituto Italiano di Tecnologia Via Morego 30 16163 Genova Italy
- 4BCMaterials, Basque Center for Materials, Applications, and Nanostructures Leioa 48940 Spain
- 5Electron Microscopy Facility, Istituto Italiano di Tecnologia Via Morego 30 16163 Genova Italy
- 6School of Materials Science and Engineering, Shanghai University Shangda Road 99 200444 Shanghai China
- 7Ikerbasque Basque Foundation for Science Bilbao 48009 Spain
- 8Photonic Nanomaterials, Istituto Italiano di Tecnologia Via Morego 30 16163 Genova Italy
Abstract
All-inorganic colloidal CsPbI3 nanocrystals are promising materials for light-emitting applications owing to their excellent optoelectronic properties. However, their practical implementation remains limited by surface defects, ligand instability, and phase degradation under ambient conditions. Here, we employ trimethyl(dodecyl)phosphonium iodide (TDP-I) as a post-synthetic ligand for partial ligand exchange on CsPbI3 nanocrystals initially coated with a ligand shell that is primarily composed of oleylammonium ions. X-ray photoelectron spectroscopy, Fourier-transform infrared spectroscopy, and nuclear magnetic resonance analyses confirm that TDP-I is only partially replacing the native ligand shell. These findings are in line with classical molecular dynamics calculations, which indicate that a mixed oleylammonium/TDP+ ligand shell is more stable than a full TDP+ one. The TDP-I treatment improved photophysical properties including an increase in the photoluminescence quantum yield (from ∼77% to ∼90%), accompanied by prolonged photoluminescence lifetime and reduced nonradiative recombination. The TDP-I-treated nanocrystals also exhibit improved stability, with delayed transformation from the orthorhombic phase to the non-perovskite δ-phase under ambient conditions. When incorporated into light-emitting diodes, the TDP-I-treated CsPbI3 nanocrystals deliver a maximum external quantum efficiency of 12.4%. These results demonstrate that partial phosphonium ligand exchange provides an effective strategy for optimizing the surface chemistry, optical properties, and device performance of CsPbI3 nanocrystals, highlighting the importance of mixed-ligand surface engineering for perovskite optoelectronics.
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BibTeX
@article{zhang2026partial,
title = {{Partial ligand exchange on CsPbI3 nanocrystals with alkyl phosphonium iodide improves phase stability and emission efficiency in light-emitting diodes}},
author = {Shence Zhang and Meenakshi Pegu and Luca Goldoni and Hossein Roshan and Umberto Filippi and Abdessamad El Adel and Francesco De Boni and Simone Lauciello and Zhanzhao Li and Yuting Song and Ivan Infante and Francesco Di Stasio and Liberato Manna},
journal = {Chemical Science},
year = {2026},
month = oct,
doi = {10.1039/d6sc06271g},
url = {https://doi.org/10.1039/d6sc06271g},
note = {CC BY 3.0},
}
RIS
TY - JOUR
TI - Partial ligand exchange on CsPbI3 nanocrystals with alkyl phosphonium iodide improves phase stability and emission efficiency in light-emitting diodes
AU - Shence Zhang
AU - Meenakshi Pegu
AU - Luca Goldoni
AU - Hossein Roshan
AU - Umberto Filippi
AU - Abdessamad El Adel
AU - Francesco De Boni
AU - Simone Lauciello
AU - Zhanzhao Li
AU - Yuting Song
AU - Ivan Infante
AU - Francesco Di Stasio
AU - Liberato Manna
PY - 2026
DA - 2026/10/07
JO - Chemical Science
DO - 10.1039/d6sc06271g
UR - https://doi.org/10.1039/d6sc06271g
AB - All-inorganic colloidal CsPbI3 nanocrystals are promising materials for light-emitting applications owing to their excellent optoelectronic properties. However, their practical implementation remains limited by surface defects, ligand instability, and phase degradation under ambient conditions. Here, we employ trimethyl(dodecyl)phosphonium iodide (TDP-I) as a post-synthetic ligand for partial ligand exchange on CsPbI3 nanocrystals initially coated with a ligand shell that is primarily composed of oleylammonium ions. X-ray photoelectron spectroscopy, Fourier-transform infrared spectroscopy, and nuclear magnetic resonance analyses confirm that TDP-I is only partially replacing the native ligand shell. These findings are in line with classical molecular dynamics calculations, which indicate that a mixed oleylammonium/TDP+ ligand shell is more stable than a full TDP+ one. The TDP-I treatment improved photophysical properties including an increase in the photoluminescence quantum yield (from ∼77% to ∼90%), accompanied by prolonged photoluminescence lifetime and reduced nonradiative recombination. The TDP-I-treated nanocrystals also exhibit improved stability, with delayed transformation from the orthorhombic phase to the non-perovskite δ-phase under ambient conditions. When incorporated into light-emitting diodes, the TDP-I-treated CsPbI3 nanocrystals deliver a maximum external quantum efficiency of 12.4%. These results demonstrate that partial phosphonium ligand exchange provides an effective strategy for optimizing the surface chemistry, optical properties, and device performance of CsPbI3 nanocrystals, highlighting the importance of mixed-ligand surface engineering for perovskite optoelectronics.
SN - 2041-6520
SN - 2041-6539
ER -