Polaronic-Distortion-Driven Enhancement of Excitonic Auger Recombination in ZnO Nanoparticles

Fuente: arXiv
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Autores principales: Hua, Fuyong, Zhang, Zheng, Wang, Zhong, Liu, Yang, Gong, Changchang, Hu, Chunlong, Zhou, Yinhua, Liang, Wenxi
Formato: Preprint
Publicado: 2025
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author Hua, Fuyong
Zhang, Zheng
Wang, Zhong
Liu, Yang
Gong, Changchang
Hu, Chunlong
Zhou, Yinhua
Liang, Wenxi
author_facet Hua, Fuyong
Zhang, Zheng
Wang, Zhong
Liu, Yang
Gong, Changchang
Hu, Chunlong
Zhou, Yinhua
Liang, Wenxi
contents The surface effect and quantum confinement render nanomaterials the optoelectronic properties more susceptible to nonradiative processes than their bulk counterparts. These nonradiative processes usually contain a series of interwoven and competing sub-processes, which are challenging to disentangle. Here, we investigate the structural origin of Auger recombination in ZnO nanoparticles using transient absorption spectroscopy and ultrafast electron diffraction. The photogenerated hot holes are captured by oxygen vacancies through an Auger mechanism, inducing significant local structural distortions around the oxygen vacancy and its neighboring zinc tetrahedron on a sub-picosecond timescale. The recombination of trapped holes accelerates the lattice thermalization and stabilizes the formed small hole polarons. Subsequently, the recombination of localized polarons forms a confined exciton-polaron complex that may account for the long-lived (>7 ns) visible luminescence observed in ZnO nanoparticles. Our findings are potentially applicable to other transition metal oxide nanomaterials, bringing insights for the optimization of their functional properties.
format Preprint
id arxiv_https___arxiv_org_abs_2511_00994
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Polaronic-Distortion-Driven Enhancement of Excitonic Auger Recombination in ZnO Nanoparticles
Hua, Fuyong
Zhang, Zheng
Wang, Zhong
Liu, Yang
Gong, Changchang
Hu, Chunlong
Zhou, Yinhua
Liang, Wenxi
Materials Science
Chemical Physics
The surface effect and quantum confinement render nanomaterials the optoelectronic properties more susceptible to nonradiative processes than their bulk counterparts. These nonradiative processes usually contain a series of interwoven and competing sub-processes, which are challenging to disentangle. Here, we investigate the structural origin of Auger recombination in ZnO nanoparticles using transient absorption spectroscopy and ultrafast electron diffraction. The photogenerated hot holes are captured by oxygen vacancies through an Auger mechanism, inducing significant local structural distortions around the oxygen vacancy and its neighboring zinc tetrahedron on a sub-picosecond timescale. The recombination of trapped holes accelerates the lattice thermalization and stabilizes the formed small hole polarons. Subsequently, the recombination of localized polarons forms a confined exciton-polaron complex that may account for the long-lived (>7 ns) visible luminescence observed in ZnO nanoparticles. Our findings are potentially applicable to other transition metal oxide nanomaterials, bringing insights for the optimization of their functional properties.
title Polaronic-Distortion-Driven Enhancement of Excitonic Auger Recombination in ZnO Nanoparticles
topic Materials Science
Chemical Physics
url https://arxiv.org/abs/2511.00994