Inserting an “atomic trap” for directional dopant migration in core/multi-shell quantum dots

Chun Chu, Elan Hofman, Chengpeng Gao, Shuya Li, Hanjie Lin, Walker MacSwain, John M. Franck, Robert W. Meulenberg, Arindam Chakraborty, Weiwei Zheng

Research output: Contribution to journalArticlepeer-review

Abstract

Diffusion of atoms or ions in solid crystalline lattice is crucial in many areas of solid-state technology. However, controlling ion diffusion and migration is challenging in nanoscale lattices. In this work, we intentionally insert a CdZnS alloyed interface layer, with small cationic size mismatch with Mn(ii) dopant ions, as an “atomic trap” to facilitate directional (outward and inward) dopant migration inside core/multi-shell quantum dots (QDs) to reduce the strain from the larger cationic mismatch between dopants and host sites. Furthermore, it was found that the initial doping site/environment is critical for efficient dopant trapping and migration. Specifically, a larger Cd(ii) substitutional site (92 pm) for the Mn(ii) dopant (80 pm), with larger local lattice distortion, allows for efficient atomic trapping and dopant migration; while Mn(ii) dopant ions can be very stable with no significant migration when occupying a smaller Zn(ii) substitutional site (74 pm). Density functional theory calculations revealed a higher energy barrier for a Mn(ii) dopant hopping from the smaller Zn substitutional tetrahedral (Td) site as compared to a larger Cd substitutional Td site. The controlled dopant migration by “atomic trapping” inside QDs provides a new way to fine tune the properties of doped nanomaterials.

Original languageEnglish (US)
Pages (from-to)14115-14123
Number of pages9
JournalChemical Science
Volume14
Issue number48
DOIs
StatePublished - Nov 20 2023

ASJC Scopus subject areas

  • General Chemistry

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