Processing and optical properties of spin-coated polystyrene films containing CdS nanoparticles

The processing, microstructure and optical properties of CdS semiconductor nanoparticles sequestered in spin-coated polymer films has been investigated. A simple processing protocol has been developed to form thin film structures consisting of CdS nanoparticles dispersed in the interstices created by a close-packed stacking of polystyrene spheres. We have decoupled the synthesis of the CdS nanoparticles from the polymer matrix by synthesizing a colloidal suspension of CdS nanoparticles in water that is compatible with a polymer latex water suspension. In this way we are able to vary the CdS concentration in the polymer him over a wide range and create concentrations of quantum dot particles two orders of magnitude larger than those reported in previous work. In contrast to the conventional reaction synthesis of nanoparticles in a polymer matrix, the present method is versatile enough to create several useful thin film polymer-semiconductor structures using a straightforward, environment-friendly spin-coating technology.