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Subject of the Master's internship

Synthesis and Characterization of Silver Chalcogenide Quantum Dots

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Published on 14 September 2023
Summary
Colloidal semiconductor nanocrystals, also termed quantum dots (QDs), have been discovered around 40 years ago. They have attracted considerable interest due to their size-dependent optical and electronic properties. In particular, their band gap can be simply changed by adjusting their size via the so-called quantum confinement effect. It occurs for many semiconductors when at least one of their dimensions is reduced to a few nanometers. Most research has been conducted on binary cadmium- and lead-based QDs (CdSe, PbS, etc.), which cover the visible and near infrared spectral range and can be easily synthesized. However, due to the toxicity of these compounds, their use in real-life applications is strongly limited. Our team is focusing on the development of toxic heavy metal-free and environmentally benign QDs and recently have begun the develop NIR emitting silver chalcogenide (Ag2X, X = S, Se, Te) QDs which have a high potential for their use in biomedical applications.
The goal of this internship is to explore Ag2X QDs, which have recently emerged as a biocompatible, near infrared emitting alternative to traditional toxic NIR emitting QDs (e.g. PbS, InAs, HgTe). The candidate will first perform the chemical synthesis of AgzX QDs in organic media of various sizes and/or compositions (Ag:X ratio). The optical (UV-Vis-NIR absorption, photoluminescence) and structural (crystal structure, morphology) properties will be characterized and the synthesis protocol optimized. Next, the student will carry out phase transfer reactions in order to render the QDs soluble in aqueous media with the potential for surface functionalization of the QDs or growth of an inorganic shell to improve their optical properties. Finally, the toxicology of the QDs in hepatic cells will be assessed in view of their future use as multi-modal theranostic probes .


Background and skills expected
Master in chemistry or materials science, hands-on experience in chemical synthesis and knowledge of optical and structural characterization techniques​. 
 

Competences that will be acquired during the internship
The candidate will benefit from an interdisciplinary research environment at the cutting edge of chemistry, physics and nanoscience. He/she will be trained in the synthesis of semiconductor quantum dots and their optical/structural characterization, and will get insight in the application of these nanoparticles in biological applications (e.g. in-vivo imaging, bio-sensing)


​information
Supervisor: Peter Reiss - Tel: 04 38 78 97 19 - Web-page.
Laboratory: SyMMES (Molecular Systems and Nanomaterials for Enregy and Health) laboratory
Team: STEP (Synthesis, Structure and Properties of Fun​ctional Materials)
This Master internship could be followed into a PhD within the same research area: eventually, depending on funding opportunities)​
1  Reiss, P.; Carrière, M.; Lincheneau, C.; Vaure, L.; Tamang, S., Synthesis of Semiconductor Nanocrystals, Focusing on Nontoxic and Earth-Abundant Materials. Chem. Rev.2016, 116, 10731-10819.
2 Gui, R.; Jin, H.; Wang, Z.; Tan, L., Recent Advances in Synthetic Methods and Applications of Colloidal Silver Chalcogenide Quantum Dots, Coordination Chemistry Reviews, 2015, 296, 91–124.
3 Jiao, M.; Portniagin, A. S.; Luo, X.; Jing, L.; Han, B.; Rogach, A. L., Semiconductor Nanocrystals Emitting in the Second Near-Infrared Window: Optical Properties and Application in Biomedical Imaging, Advanced Optical Materials, 2022, 10.