Formation of Near-IR Excitons in Low-Dimensional CuSbS2

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A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
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Journal of Physical Chemistry C, Volume 125, issue 38
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.
Funding Information: This work was performed as part of the Academy of Finland RADDESS project 314488 and QTF Centre of Excellence program (project 312298) (KC, TAN). We acknowledge computational resources provided by the CSC – IT Center for Science (Finland) and by the Aalto Science-IT project (Aalto University School of Science). The work was supported in part by the High Performance Computing Centre Stuttgart (HLRS) and HPC-Europa3. C.C. acknowledges financial support from the German Research Foundation, project number 182087777 (CRC 951), from the German Federal Ministry of Education and Research (Professorinnen programm III), and from the State of Lower Saxony (Professorinnen für Niedersachsen). Publisher Copyright: © 2021 The Authors. Published by American Chemical Society.
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Conley , K M , Cocchi , C & Ala-Nissila , T 2021 , ' Formation of Near-IR Excitons in Low-Dimensional CuSbS 2 ' , Journal of Physical Chemistry C , vol. 125 , no. 38 , pp. 21087–21092 .