SPR sensitivity of silver nanorods in CsBr-Ag nanocomposite thin films

We have investigated the optical and morphological properties of CsBr-Ag complex thin films deposited by thermal evaporation on glass substrate. By varying the thickness of the film with fixed mass ratio of cesium bromide and silver, we observed a broad absorption peak in the visible region from 350 to 450 nm corresponding to the transverse and longitudinal surface plasmon resonance (SPR) mode. Red shift is observed, with varying film thickness, in SPR peak position corresponding to longitudinal mode with no significant change in transverse mode due to variation in the aspect ratio of the silver nano crystalline grains. Scanning electron microscope and EDX revealed the formation of silver nanorods in film samples. Such, stable and tunable CsBr-Ag films can be used in optical filters.