Oral: Understanding growth dynamics and stability of Hydrothermally synthesized TMDCs QDs

Quantum dots (QDs), due to their non-trivial optical properties, have emerged as one of the most exciting and advanced materials, the major reason being the Quantum confinement effect. Hydrothermal synthesis offers the challenge of stability leading to the unexpected size non-uniformity among the produced QDs. We aim to discuss, through various morphological and optical observation, the fundamental study of the evolution of hydrothermally synthesized Molybdenum Disulfide QDs considering 'reaction time' as the controlling parameter. We claim that QDs show nucleation, growth, sheet formation (through aggregation) for a smaller reaction time (<14 hours), and sheet fragmentation leading to the formation of smaller-sized QDs at larger reaction times (>18 hours). Fractal Analysis was used to understand the compactness of the QD sheets. At smaller times sheets showed compact behavior and with increased reaction time fractal nature, producing a lower fractal dimension which got saturated at 1.82. Fragmentation events, being the main reason behind the decrease in QD sizes, estimated through fractal analysis of the QD sheets prepared through aggregation of the QDs. Such QDs also shows a higher stability while dispersing in a solvent other than water, hinting towards a long standing problem or size uniformity during QD production by reducing the aggregation events.