Synthesis and Characterization of Quantum Dots Based on Transition Metal Dichalcogenides

Atomically transition metal dichalcogenides (TMDs) have attracted a significant attention due to their novel and promising physical properties. However, Quantum Dots (QDs) based on TMDs have been less studied. QDs present size-dependent optical and electronic properties due to quantum confinement of electrons and phonons. Consequently, they have potential applications in medicine, renewable energy, and electronics, among others. In this presentation we will describe a simple synthetic approach to produce TMD-based QDs as well as the study of their physical properties. The synthesis involves mechanical rupture of large TMD flakes using a high power ultrasonic horn, bath sonication and/or thermal reflux. Subsequently, QDs of different sizes are selected by centrifugation. The effect of different parameters such as ultrasonic power, time, solvent type and centrifugation conditions on the final size distribution were studied. The morphology of the TMD fragments was studies by scanning electron microscopy and atomic force microscopy. The optical response of the as-prepared materials was evaluated using optical absorption spectroscopy, photoluminescence and Raman spectroscopies.