Effect of PbS nanocrystal concentration on the physical properties of a polymer–nanocrystal composite

Semiconductor nanocrystals doped in stable matrices such as polymers are of interest due to fundamental scientific aspects as well as their scope for technological applications. In the present investigation, PbS nanocrystals are synthesized in polyvinyl alcohol (PVA) matrix using a simple technique based on colloidal chemistry. Various concentrations of nanocrystalline PbS (with an average size of 4.5 nm) are loaded into the polymer to study the effect of PbS concentration on the optical, thermal and electrical properties of the composite. An increase in PbS content results in decrease in thermal stability and an increase in electrical conductivity, presumably resulting from interactions between the nanofiller and polymer. Considerations for designing composites with desired combinations of electrical, thermal, and optical properties to suit specific device operating environments are studied systematically.