Effects of Repetitive Pressure on the Photoluminescence of Bare and ZnS-Capped CuInS₂ Quantum Dots: Implications for Nanoscale Stress Sensors

Abstract

Semiconductor quantum dots (QDs) are promising materials for stress/strain sensing applications owing to their pressure-dependent photoluminescence (PL) and nanoscale size, while the impact of stress and microstructure on their optical properties still awaits in-depth investigations under more realistic loading conditions. Herein, bare CuInS2 QDs and core–shell structured CuInS2/ZnS QDs are investigated under repetitive pressure loadings to elucidate the pressure-dependent PL responses over many pressure cycles. The CuInS2/ZnS QDs not only show higher PL intensity but also exhibit a reliable and simple relationship between PL emission peak energy (E PL) and external pressure (P), which is desirable for actual application in stress/strain sensing. Specifically, the E PL–P relationship of bare CuInS2 QDs changes after the first loading–unloading cycle, while the E PL–P relationship of CuInS2/ZnS QDs shows repeatable trajectories under different cycles. This research provides experimental support for designing QD-based stress/strain sensing materials and explains how the shell and surface microstructure will affect the mechanical-luminescence responses of QDs.

Bright, Magnetic NIR-II Quantum Dot Probe for Sensitive Dual-Modality Imaging and Intensive Combination Therapy of Cancer

“…Along with this process, the NIR-II fluorescence was greatly enhanced with shell growth time (Figure S3a). The initial blueshift or increase in the quantum confinement arises from the shrinkage in the emissive core size, likely due to near-surface Zn 2+ diffusion, which has been observed in our previous studies. ,− This can be attributed to neither the further growth nor the ripening of the underlying CISe cores, although the unpurified CISe cores directly served as the seeds for further shell growth in the presence of excess CISe precursors. CISe nanocrystals possess a chalcopyrite structure as a slightly modified form of zinc blende, where Cu + and In 3+ ions occupy the Zn 2+ sites.…”

Pressure and Composition Effects on a Common Nanoparticle Ligand–Solvent Pair

“…Pressure is an important variable to consider in the study of the fundamental properties of nanoparticles and the role of size and increased surface area in determining the said properties. Size dependence in high-pressure phase diagrams has been observed in metallic and semiconductor nanocrystals, − and similar studies have reported intriguing pressure-dependent optical − and mechanical − properties of nanocrystals and their assemblies.…”

Synthesis and hybridization of CuInS2 nanocrystals for emerging applications

“…More details on the use of CuInS 2 -based NCs for bioapplications such as in vitro / in vivo imaging of cancer cells, in vivo tracking/visulization of tissues, multi-modal imaging and threanostics, can be found in a recent review article by Ceroni and co-workers. 255 It should be mentioned that with bright luminescence, CuInS 2 -based NCs are also suitable as luminescent sensors for pH, 256 temperature 257,258 and stress 259,260 detection in the biomedical field.…”