Formation of Near-IR Excitons in Low-Dimensional CuSbS2

Kevin M. Conley, Caterina Cocchi, Tapio Ala-Nissila*

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

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Abstract

The electronic and optical properties of low-dimensional semiconductors are typically quite different from those of their bulk counterparts. Yet, the optical gap of two-dimensional copper antimony disulfide (CuSbS2) does not dramatically change with decreasing thickness of the material. The absorption onset remains at about 1.5 eV in the monolayer, bilayer, and bulk materials. Using density functional theory and many-body perturbation theory, we rationalize this behavior through the interplay of quantum confinement, electron-hole interactions, and the formation of surface states. Specifically, the spatial confinement in thin layers induces strongly bound optical transitions in the near-infrared region. Our results explain the optical properties in copper antimony disulfide platelets of varying thickness and set these materials as potential candidates for novel photovoltaic devices and near-infrared sensors.

Original languageEnglish
Pages (from-to)21087–21092
Number of pages6
JournalJournal of Physical Chemistry C
Volume125
Issue number38
Early online date20 Sep 2021
DOIs
Publication statusPublished - 30 Sep 2021
MoE publication typeA1 Journal article-refereed

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