Morphology, Structural and Electrical Properties of Ag–Cu Alloy Nanoparticles Embedded in PVA Matrix and Its Performance as E. coli Monitoring Sensor

A new low-cost, simple and clean method for microbial monitoring sensor based on bimetallic thin film is fabricated in this research. The nanocomposite of Ag–Cu doped with PVA has been synthesized via sol–gel method and deposited on glass substrate. Ag–Cu alloy thin films with various concentrations were characterized using XRD, FTIR, UV–Vis, AFM, TEM and I –V measurement. The peaks in XRD pattern confirm the presence of Ag, Cu and Ag–Cu alloy nanoparticles in FCC structure. FTIR spectra found the O–H stretching of hydroxyl group and C–H stretching of PVA. The resonance UV–Vis absorption peaks are all sharp and lie between the wavelengths of 296–299 nm. The surface of the films has been found to be smoother as the Cu concentrations increased. The sensor performance was tested by measuring the changes of current of the film using I –V measurement. The Ag0.2–Cu0.8 alloy film shows obvious changes in current when it was incubated with E. coli. The sensitivity measurement, S, shows that the high sensitivity can be observed at higher concentrations of Cu.