Transparent semiconductor–polymer hybrid films with tunable optical properties

Abstract

Size confined CdS nanoparticles with controlled size and narrow particle size distribution were synthesized in transparent adhesive polyelectrolyte films, which are composed of chitosan (CHI), poly(monomethyl itaconate) (PMMI) and silica (SiO₂) in variable amounts. This room temperature synthesis in an aqueous environment avoids the toxic and high temperature conditions usually associated with the synthesis of high quality semiconductors. The semiconductor particle size could be controlled via the Cd²⁺ concentration and the amine groups of chitosan were identified to be of importance for the coordination of the semiconductor. The films were characterized by UV-Vis and fluorescence spectroscopy, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectra and the adsorption behavior of Cd²⁺ to the films was characterized by Langmuir and Freundlich isotherms.