The fabrication, characterization, and CO 2 gas detection performance of single component-based and hetero-nanostructure-based optical gas sensors are reported in the present work. Single component-based structures include (i) TiO 2 thin films with varied film thickness (37.45 nm, 51.92 nm, and 99.55 nm) fabricated via the RF sputtering system for different deposition times and (ii) silver nanoparticles (AgNPs) deposited on the glass substrate by the wet chemical method. Hetero-nanostructures were achieved by decorating the AgNPs on the predeposited TiO 2 thin films. The structural, morphological, and optical characteristics of prepared samples were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), and ellipsometry, respectively. XRD analysis of AgNPs confirmed the crystalline nature of prepared particles with average crystallite size of 21 nm, however, in the case of TiO 2 films XRD results suggested amorphous structure of all as-deposited films. size 21 nm. The SEM micrographs confirmed the deposition of AgNPs on the TiO 2 thin films. With increasing sputtering time, TiO 2 films were found to be denser and more compact, indicating a reduced porosity and higher film thickness. CO 2 gas-sensing properties were investigated by measuring the optical transmission spectra in alone air and in CO 2 gaseous atmosphere at room temperature. It was observed that neither TiO 2 thin films even with higher thickness nor alone AgNPs could demonstrate any substantial gas-sensing activity. Nevertheless, TiO 2 /AgNP hetero-nanostructured substrates exhibited excellent CO 2 gas-sensing performance as indicated by a huge change in the transmission spectra. The enhanced sensing efficiency of TiO 2 /AgNP nanostructures owing to synergistic effects suggests a promising role of our manufactured sensors in practical applications.
Raza, M. A., Habib, A., Kanwal, Z., Hussain, S. S., Iqbal, M. J., Saleem, M., … Naseem, S. (2018). Optical CO 2 Gas Sensing Based on TiO 2 Thin Films of Diverse Thickness Decorated with Silver Nanoparticles . Advances in Materials Science and Engineering, 2018, 1–12. https://doi.org/10.1155/2018/2780203