Influence of Mn/S molar ratio on the microstructure and optical properties of MnS nanocrystals synthesized by wet chemical technique

Abstract

Manganese sulfide (MnS) microparticles have been successfully synthesized at three different Mn/S ratios of 1:1, 1:2 and 2:1 by wet chemical technique. The effect of molar ratio on crystal structures, morphologies and optical properties of as-prepared sample has been investigated. The particle size, micro strain and dislocation density of MnS particles have been estimated by modified Scherrer formula from X-ray diffraction peak broadening analysis. It has also identified the phase transformation from the metastable β-MnS into γ-MnS microparticles. This work presents the results of morphological characterization by scanning electron microscope. It is evident from the SEM image that MnS particles are almost spherical in shape. The UV–Visible absorption study revealed to determine the optical band gap of the MnS microparticles which shows a blue shift with decreasing particle size and the observed band gap lies in the range of 6.03–4.70 eV. The photoluminescence spectrum of as-prepared samples showed that the two main emission peaks corresponding to the strong UV blue emissions.