Trap Passivation in Indium-Based Quantum Dots through Surface Fluorination: Mechanism and Applications
Abstract
Treatment of InP colloidal quantum dots (QDs) with hydrofluoric acid (HF) has been an effective method to improve their photoluminescence quantum yield (PLQY) without growing a shell. Previous work has shown that this can occur through the dissolution of the fluorinated phosphorus and subsequent passivation of indium on the reconstructed surface by excess ligands. In this article, we demonstrate that very significant luminescence enhancements occur at lower HF exposure though a different mechanism. At lower exposure to HF, the main role of the fluoride ions is to directly passivate the surface indium dangling bonds in the form of atomic ligands. The PLQY enhancement in this case is accompanied by red shifts of the emission and absorption peaks rather than blue shifts caused by etching as seen at higher exposures. Density functional theory shows that the surface fluorination is thermodynamically preferred and that the observed spectral characteristics might be due to greater exciton delocalization over the outermost surface layer of the InP QDs as well as alteration of the optical oscillator strength by the highly electronegative fluoride layer. Passivation of surface indium with fluorides can be applied to other indium-based QDs. PLQY of InAs QDs could also be increased by anmore »
- Authors:
-
[3];
[6]
- Samsung Advanced Institute of Technology, Suwon (Korea); Univ. of California, Berkeley, CA (United States)
- Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
- Univ. of California, Berkeley, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Technion-Israel Inst. of Technology, Haifa (Israel)
- Univ. of California, Berkeley, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
- Samsung Advanced Inst. of Technology, Suwon (Korea)
- Univ. of California, Berkeley, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Kavli Energy NanoScience Inst., Berkeley, CA (United States)
- Publication Date:
- Research Org.:
- Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
- Sponsoring Org.:
- USDOE Office of Science (SC)
- OSTI Identifier:
- 1545143
- Grant/Contract Number:
- AC02-05CH11231
- Resource Type:
- Accepted Manuscript
- Journal Name:
- ACS Nano
- Additional Journal Information:
- Journal Volume: 12; Journal Issue: 11; Journal ID: ISSN 1936-0851
- Publisher:
- American Chemical Society (ACS)
- Country of Publication:
- United States
- Language:
- English
- Subject:
- 37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; indium phosphide; quantum dots; fluorine; etching; atomic ligand; indium arsenide
Citation Formats
Kim, Tae -Gon, Zherebetskyy, Danylo, Bekenstein, Yehonadav, Oh, Myoung Hwan, Wang, Lin -Wang, Jang, Eunjoo, and Alivisatos, A. Paul. Trap Passivation in Indium-Based Quantum Dots through Surface Fluorination: Mechanism and Applications. United States: N. p., 2018.
Web. doi:10.1021/acsnano.8b06692.
Kim, Tae -Gon, Zherebetskyy, Danylo, Bekenstein, Yehonadav, Oh, Myoung Hwan, Wang, Lin -Wang, Jang, Eunjoo, & Alivisatos, A. Paul. Trap Passivation in Indium-Based Quantum Dots through Surface Fluorination: Mechanism and Applications. United States. doi:10.1021/acsnano.8b06692.
Kim, Tae -Gon, Zherebetskyy, Danylo, Bekenstein, Yehonadav, Oh, Myoung Hwan, Wang, Lin -Wang, Jang, Eunjoo, and Alivisatos, A. Paul. Tue .
"Trap Passivation in Indium-Based Quantum Dots through Surface Fluorination: Mechanism and Applications". United States. doi:10.1021/acsnano.8b06692. https://www.osti.gov/servlets/purl/1545143.
@article{osti_1545143,
title = {Trap Passivation in Indium-Based Quantum Dots through Surface Fluorination: Mechanism and Applications},
author = {Kim, Tae -Gon and Zherebetskyy, Danylo and Bekenstein, Yehonadav and Oh, Myoung Hwan and Wang, Lin -Wang and Jang, Eunjoo and Alivisatos, A. Paul},
abstractNote = {Treatment of InP colloidal quantum dots (QDs) with hydrofluoric acid (HF) has been an effective method to improve their photoluminescence quantum yield (PLQY) without growing a shell. Previous work has shown that this can occur through the dissolution of the fluorinated phosphorus and subsequent passivation of indium on the reconstructed surface by excess ligands. In this article, we demonstrate that very significant luminescence enhancements occur at lower HF exposure though a different mechanism. At lower exposure to HF, the main role of the fluoride ions is to directly passivate the surface indium dangling bonds in the form of atomic ligands. The PLQY enhancement in this case is accompanied by red shifts of the emission and absorption peaks rather than blue shifts caused by etching as seen at higher exposures. Density functional theory shows that the surface fluorination is thermodynamically preferred and that the observed spectral characteristics might be due to greater exciton delocalization over the outermost surface layer of the InP QDs as well as alteration of the optical oscillator strength by the highly electronegative fluoride layer. Passivation of surface indium with fluorides can be applied to other indium-based QDs. PLQY of InAs QDs could also be increased by an order of magnitude via fluorination. We fabricated fluorinated InAs QD-based electrical devices exhibiting improved switching and higher mobility than those of 1,2-ethanedithiol cross-linked QD devices. The effective surface passivation eliminates persistent photoconductivity usually found in InAs QD-based solid films.},
doi = {10.1021/acsnano.8b06692},
journal = {ACS Nano},
number = 11,
volume = 12,
place = {United States},
year = {2018},
month = {10}
}
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