Comparative optical sensing studies of silver nanowires prepared by different synthetic routes

The silver nanowires (AgNWs) have been synthesized by two different methods: polyol and hydrothermal. The X-ray diffraction analysis (XRD) revealed the face-centered cubic (fcc) structure. Morphological analysis shows the nanowire dimensions are ~ 60–80 nm in width and more than 10 μm in length. The optical gas sensing study of AgNWs was carried out at room temperature against various gases and VOCs such as, SO_x, NO_x, ammonia, acetonitrile, methanol, acetone, formaldehyde, triethylamine, trimethylamine and ethanol. Among these, the AgNWs synthesized by polyol method with mediating agent exhibited higher sensitivity towards ammonia vapours (~ 95% at 100 ppm concentration of ammonia). The sensing response against ammonia vapours was studied in the concentration range of 100–1000 ppm at room temperature. The linear response was obtained which is useful for device fabrication.