Influence of calcination temperature on the growth of electrospun multi-junction ZnO nanowires: A room temperature ammonia sensor

Chemiresistive gas sensors play a significant role in human exhaled breath analysis for non-invasive disease diagnosis applications. Ammonia has been considered as one of the prominent biomarkers, which is present in the exhaled breath of persons affected by chronic kidney disease (CKD). In this context, polyvinyl pyrrolidine (PVP) - zinc oxide (ZnO) nanofibers based chemiresistive gas sensor has been developed for the detection of ammonia at room temperature. PVP-ZnO nanofibers were synthesized using electrospinning technique with an applied potential of 20 kV. The synthesized nanofibers were calcined in the temperature range of 200–700°C in steps of 100°C. The influence of calcination temperature on the structural, morphological, electrical and optical properties were investigated using various characterization techniques. Further, calcinated samples were drop cast onto the Ag/Pd electrode for sensing studies using a homemade gas chamber integrated with high resistance electrometer. The sample calcined at 500°C showed a selective response towards ammonia with a response of 20 towards 50 ppm, and response and recovery times of 88 and 65 s.