Plasmon resonance-induced photoluminescence enhancement of CdS quantum dots thin films on fabricated Au/Ag/Cu metallic thin films

Abstract

Multi-metallic nanoparticles (NPs) offer tunable Localized Surface Plasmon Resonance properties which depend on their elemental and configurational variations, which have been used in optical sensing and biomedical imaging. In the present study, the composition and optical properties of hybrid nano-structured thin films of CdS quantum dots (QDs) incorporated on Au-, Ag- and Cu-NPs for photonic applications are investigated. Initially, CdS QDs were prepared by chemical reduction method and characterized by Transmission electron microscopy, UV–Visible absorption spectroscopy and Fourier transform infrared spectroscopy techniques. Then nanometer thin films of Au, Ag and Cu were fabricated by thermal evaporator and insitu heating along with uniform rotation of substrate was used to convert these into respective uniform spherical NPs on ITO substrate. Further, CdS QDs were deposited over these metallic NPs and we observed enhanced photoluminescence (PL) of CdS QDs due to Surface Plasmon Resonance effect by these metallic NPs. The time resolved spectroscopy of these films was carried out to correlate the enhanced PL emission from CdS–Au–Ag–Cu-ITO thin film. The results of the present study of these plasmonic nanostructures will be further utilized in metal enhanced fluorescence sensors.