Ab initio investigations on the structural and optical properties of sol-gel synthesized bismuth telluride nanoparticles

Bismuth telluride nanopowders are prepared by a simple but efficient wet chemical synthesis route namely Sol-gel auto-combustion. X-ray diffraction (XRD) and Scanning Electron Microscopic (SEM) analyses were used to study the structural and morphological characteristics. The crystallinity of the produced samples were verified using XRD, and composition was confirmed by Energy Dispersive x-ray analysis (EDAX) measurements. The optical characterization of the prepared bismuth nanopowders were also carried out using Diffused Reflectance Spectroscopy (DRS) and Raman spectroscopic analysis. The optical bandgap of the prepared nanopowder is found to be 3.27 eV. Raman active modes of the sample are also reported. The optical properties of the Bismuth telluride nanopowder are rarely reported. The optical constant evaluation of the prepared sample point towards the probable application of these materials in optoelectronic devices in addition to its conventional thermoelectric applications.