Synthesis route and optical characterization of CdS:Mn/polyvinyl alcohol nanocomposite

Abstract

CdS nanoparticles doped with Mn have been synthesized in aqueous solution by using polyvinyl alcohol (PVA) as a capping reagent. Influence of the polymer concentration on the size and concentration of the nanoparticles was studied using transmission electron microscopy and optical absorption. Incorporation of Mn²⁺ ions into CdS nanoparticles was confirmed by photoluminescence (PL) intensity increase and band shift with Mn concentration. The PL studies proved that localization of Mn ions (inside the nanoparticles or on the surface) depends on the sequence of synthesis steps. The bleaching of the low-energy PL band of the low-doped CdS:Mn nanoparticles by surface modification with a Cd(OH)₂ layer proves suppression of the emission related to surface states.