Investigation of Ethanol gas sensing properties of pristine and Al doped ZnO nanoparticles synthesized by Sol-gel method

Abstract

Pure and Aluminum-doped Zinc Oxide nanoparticles were prepared by using a simple Sol–gel method. Al contents were varied with 1 wt% and 3 wt% at a fixed concentration of pure ZnO. Synthesized samples were calcinated at 400 °C for 2 h. The results of x-ray diffraction (XRD) confirm that the synthesized nanoparticles have a Hexagonal Wurtzite structure. The average crystallite size of the nanoparticles shows variation from 16 nm to 21 nm. Grain size and surface morphology were investigated with the help of a Field Emission Scanning Electron Microscope (FESEM). Functional groups present in the prepared samples were analyzed by using Fourier Transform Infra-red spectroscopy (FTIR). The percentage response of the fabricated sensor, containing Al-doped ZnO nanoparticles, was examined with exposure to the toxic gas Ethanol. It was observed that percentage response changes due to various sensing parameters like response time and percentage response which, were calculated at 100 ppm and 200 ppm concentrations of toxic Ethanol gas. It was found that with an increase in Al concentration as well as Ethanol ppm level the percentage response of synthesized samples is increased. The maximum percentage response of 17.82 and 20.91 at 100 and 200 ppm with 3 wt% of Al-doped ZnO nanoparticles was observed respectively, which is greater than that of pure ZnO. Also, the same sample shows the lowest response time of 215 s and 120 s at 100 ppm and 200 ppm, respectively. Thus, aluminum doping enhanced the gas sensing response of pristine zinc oxide nanoparticles.