Optical and electrical evaluation of Ag0.5Cu0.75O introduced poly(vinyl alcohol) based E.Coli sensors

Silver doped copper oxide (Ag0.5Cu0.75O) nanoparticles synthesized by hydrothermal growth process were introduced into PVA matrix in varying amounts viz., 0.5, 1.0, 2.0 and 4.0 wt% through solution intercalation method. The Ag0.5Cu0.75O nano filler induced structural and morphological changes in PVA were ascertained through X-ray diffraction and scanning electron microscopic analysis. While, the changes in optical and electrical behaviors such as optical band gap, refractive index, extinction co-efficient and current (I)-voltage (V) characteristics were established by various state of the art opto-electronic characterizations. The sensor performance was put through its pace by measuring the changes in current output of the composite films upon Escherichia coli exposure. The I-V measurements depicted 2 wt% as the optimum concentration of Ag0.5Cu0.75O nano fillers in PVA that achieved a device sensitivity of 23.85% for an E.Coli concentration of 1.25 x 10(8) cfu/ml. Under optimized conditions, the 2 wt% Ag0.5Cu0.75O/PVA based E.Coli sensor exhibited a lower detection limit of 10(2) cfu/ml and a response time of 6-8 s. The as prepared E.Coli sensor presents lower detection limit and lesser response time to be used for real-time operations.