Preparation and optical properties of nanocomposite film of CdS:Cu with biomacromolecules

Nanocomposite films of CdS:Cu nanoparticles with chitosan and sodium alginate were prepared using spin‐coating method, and characterized by X‐ray diffraction, transmission electron microscopy, atomic force microscopy (AFM), ultraviolet–visible (UV–vis), and photoluminescent spectrum. The CdS:Cu nanoparticles have a cubic structure with an average crystal size of ∼2 nm, which show blue shift in UV–vis absorption spectra compared to bulk CdS. Furthermore, the CdS:Cu nanoparticles are formed steadily with increasing number of composite layers and homogeneously distributed between the chitosan and alginate layer. AFM measurement shows that the average height of a mono‐layered composite film is 25 nm. Emissions ascribed to the electron–hole recombination of CdS and the t₂‐like energy level of Cu was observed for the multi‐layered composite films. POLYM. COMPOS., 35:477–481, 2014. © 2013 Society of Plastics Engineers