Effects of Interfacial Oxidative Layer Removal on Charge Carrier Recombination Dynamics in InP/ZnSexS1- x Core/Shell Quantum Dots

Ying-Chih Pu; Hsiao-Chuan Fan; Jui-Cheng Chang; Yu-Hung Chen; Shih-Wen Tseng

doi:10.1021/acs.jpclett.1c02125

Effects of Interfacial Oxidative Layer Removal on Charge Carrier Recombination Dynamics in InP/ZnSe_xS_{1- x} Core/Shell Quantum Dots

J Phys Chem Lett. 2021 Aug 5;12(30):7194-7200. doi: 10.1021/acs.jpclett.1c02125. Epub 2021 Jul 26.

Authors

Ying-Chih Pu¹, Hsiao-Chuan Fan¹, Jui-Cheng Chang^{2

3}, Yu-Hung Chen⁴, Shih-Wen Tseng⁵

Affiliations

¹ Department of Materials Science, National University of Tainan, Tainan 70005, Taiwan.
² Department of Chemical and Materials Engineering, National Yunlin University of Science and Technology, Douliu, Yunlin 64002, Taiwan.
³ Bachelor Program in Interdisciplinary Studies, National Yunlin University of Science and Technology, Douliu, Yunlin 64002, Taiwan.
⁴ Department of Medicine, College of Medicine, National Cheng Kung University, Tainan 70101, Taiwan.
⁵ Core Facility Center of National Cheng Kung University, Tainan 70101, Taiwan.

PMID: 34309384
DOI: 10.1021/acs.jpclett.1c02125

Abstract

Red-light-emitting InP/ZnSe_xS_1-x core/shell quantum dots (QDs) were prepared by one-pot synthesis with optimal hydrogen fluoride (HF) treatment. Most of the surficial oxidative species could be removed, and the dangling bonds would be passivated by Zn ions for the InP cores during HF treatment, which would be beneficial to the subsequent ZnSe_xS_1-x shell coating. Three-dimensional time-resolved photoluminescence spectra of the QD samples were analyzed by singular value decomposition global fitting to determine the radiative and nonradiative lifetimes of charge carriers. A proposed model illustrated that the charge carriers in the InP/ZnSe_xS_1-x QDs with interfacial oxidative layer removal would evidently recombine through radiative pathways, mainly from the conduction band to the valence band (lifetime, 33 ns) and partially from the trap states (lifetime, 150 ns). This work offers the important physical insight into the charge carrier dynamics of low-toxicity QDs which have the desired optical properties for optoelectronic applications.