Enhanced NO2 gas sensing performance of Gd/Li co-doped ZnO thin films

In this paper, we demonstrate pure, Gd-doped, and Gd/Li co-doped ZnO nanostructures for NO2 gas sensing applications fabricated via the sol-gel spin coating route. The synthesized samples are examined through various characterization techniques to evaluate their physical and chemical properties. The gas sensing performance of all deposited samples was investigated at different temperatures (150-240 degrees C) towards 75 ppm of NO2 gas. Among them, the Gd/Li co-doped ZnO sample shows remarkable NO2 gas sensing performance of 55.18 at a working temperature of 210 degrees C. Also, the gas sensitivity of Gd/Li: ZnO towards various toxic gases, including Cl-2, NH3, NO, and NO2, were studied and appeared most selective towards NO2 gas. A possible NO2 gas sensing mechanism was discussed and correlated with structural, morphological, electrical, and spectral studies.