Ag-doped ZnO nanoellipsoids based highly sensitive gas sensor

Herein, we report the facile synthesis, characterization and methanol gas sensing application of Ag-doped ZnO nanoellipsoids (NEs). The NEs were synthesized by a simple hydrothermal method and characterized by several techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM) attached with energy dispersive spectroscopy (EDS), Fourier transform infrared (FTIR), UV-visible and Raman-scattering spectroscopy. The detailed characterizations confirmed the high-density growth, well-crystallinity and wurtzite hexagonal phase of the synthesized Ag-doped ZnO NEs. The morphological studies revealed the average width at the center and length of Ag-doped ZnO NEs are ∼110 nm and ∼250 nm, respectively. A theoretical band gap energy of ∼3.26 eV was observed for NEs from the UV-Vis. spectroscopy. Further, the NEs were used as potential scaffold for the fabrication of methanol (CH3OH) gas sensor. The performance of the fabricated sensors was evaluated at 270, 320, and 370 °C and it was observed that the sensors exhibited best sensing performance at 370 °C. At optimized sensing temperature (370 °C), the fabricated sensor unveiled a gas response of 15.831 for 200 ppm of methanol gas. The response (τres) and recovery (τrec) times measured from the voltage response transient of 100 ppm methanol gas at an optimized temperature of 370 °C were 11 s and 18 s, respectively.