Microwave Assisted Zinc Sulphide Quantum Dots for Energy Device Applications

Research Lab for Energy Systems, Department of Physics, Netaji Subhas University of Technology, Delhi, India

^* Corresponding author: peeyush.phogat@gmail.com

Abstract

Zinc sulfide (ZnS) quantum dots (QDs) have received a lot of attention because of their potential usage in solar cell applications. The present work illustrates a straightforward green synthesis route for ZnS QDs, which is both cost-effective and environmentally friendly. The phase identification of the synthesized material was performed through the X-ray diffraction technique which revealed the presence of single-phase zinc sulfide. The crystallite size was calculated through various techniques such as Debye Scherrer’s, Williamson Hall and Size-Strain plot revealing quantum confinement effects. High-resolution transmission electron microscope (HR-TEM) revealed the presence of quantum dots within the quantum size range and demonstrated excellent quantum yield. However, the decrease in the particle size has increased the band gap for ZnS QDs to 3.4 eV with a refractive index of 2.29. The polycrystalline character of the as-synthesized ZnS was shown by the selected area electron diffraction (SAED) pattern of the corresponding TEM images. Morphological analysis, carried out via field emission scanning electron microscopy (FESEM), unveiled the existence of zinc sulfide quantum dots agglomerates. Elemental composition analysis was performed using energy dispersive spectroscopy (EDS) as an attachment to FESEM, which confirmed the existence only of zinc and sulphur.