Communication Dans Un Congrès Année : 2024

Progress in the Synthesis of Near-Infrared Core/Shell Quantum Dots

Résumé

Near- and short-wave infrared (NIR/SWIR) active quantum dots have attracted considerable interest for applications in biotechnology, energy conversion and optoelectronics. Most research has been conducted on binary lead- and mercury-based QDs due to the comparable simplicity of their synthesis and their outstanding properties. RoHS (Restriction of Hazardous Substances in Electrical and Electronic Equipment)-compliant III-V compounds such as InAs and InSb are currently emerging, but their more covalent character, high oxidation sensitivity and scarcity of appropriate group-V precursors make it much more challenging to achieve precise control of their size, shape and surface state. This presentation will focus on novel types of PbS-based core/shell structures. For the PbS core QD synthesis, a library of thioureas was synthesized as the sulfur precursors, which gave rise to a broad size range, excellent monodispersity and high reaction yield. This approach was also adapted to the continuous flow synthesis of larger amounts of QDs. A widely adopted strategy to enhance the PLQY of PbS QDs consists of their overcoating with a CdS shell using Pb/Cd cation exchange. Nonetheless, this procedure leads to a continuous blue-shift of the emission wavelength with proceeding cation exchange, while the PL intensity goes through a maximum, making it difficult to optimize the emission for a desired wavelength. To avoid cation exchange, we added an intermediate buffer shell of ZnS on the PbS core QDs before growing the CdS shell. We present the optical and structural properties of the novel PbS/ZnS/CdS core/shell/shell QDs as a function of the different shell thicknesses and compare them with results from ab-initio simulations on slabs of these structures. In an extension of this study, PbS/CdS QDs obtained via cation exchange have been overcoated using a reactive monomolecular precursor to obtain PbS/CdS/CdS thick-shelled QDs. Finally, our current progress on InAs-based core/shell structures will be presented.

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Dates et versions

hal-04943999 , version 1 (12-02-2025)

Identifiants

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Pierre Machut, Oleksandra Yeromina, Gabriel Mugny, Jing Li, Jonathan Steckel, et al.. Progress in the Synthesis of Near-Infrared Core/Shell Quantum Dots. Materials for Sustainable Development Conference (MATSUS Fall 24), Nov 2024, Lausanne, Switzerland. ⟨10.29363/nanoge.matsusfall.2024.238⟩. ⟨hal-04943999⟩
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