Synthesis and Characterization of Mn Doped CdS Quantum Dots from a Single Source Precursor

Abstract

ABSTRACTCdS and Mn-doped CdS capped with TOPO (tri-n-octylphosphineoxide) have been prepared by a single source route using bis(methylhexyldithiocarbamato)cadmium(II) and manganese dichloride as precursors. The nanoparticles obtained show quantum size effects in their optical spectra with the CdS nanoparticles exhibiting near band-edge luminescence. The PL spectrum of the doped CdS nanoparticles have an emission maximum at 585 nm attributed to the 4T1-6A1 electronic transition of Mn in a tetrahedral site. However the PL spectrum changes over time (weeks) and gave a deep trap emission. The Selected Area Electron Diffraction (SAED) and X-ray diffraction (XRD) pattern show both CdS and the Mn doped CdS particles to be of the hexagonal phase. Transmission Electron Microscopy (TEM) and High Resolution TEM show well-defined images of nanosize particles with clear lattice fringes. ESR spectra and ICP results confirm the presence of Mn in the CdS nanoparticles.