Designing of screen-printed stannous oxide (SnO2) thick film sensors modified by cobalt and nitrogen elements for sensing some toxic gases and volatile organic compounds

Abstract

The present research deals with fabrication of undoped SnO2, Co2+ doped SnO2 and nitrogen doped SnO2 nanostructures. These three materials were prepared by cost effective co-precipitation method. While the thick film sensors of the prepared materials was design by screen printing photolithography technique. The fabricated materials were characterized by several techniques. The structural properties of the screen-printed thick films measured by X-ray diffractometer (XRD), which confirms the formation of tetragonal SnO2 nanoparticles with average particle size between 15 and 17 ​nm. The morphological properties of fabricated thick of SnO2 were studied by scanning electron microscopy (SEM), and high-resolution transmission electron microscopy (HR-TEM) to get surface and lattice characteristics of prepared material. The EDS technique was utilized to get the elemental composition of the prepared thick film sensors. While the UV-DRS technique was used to get the band gap energy of undoped SnO2 and modified SnO2 sensors. Additionally, the materials were investigated by means of Brunauer-Emmett-Teller (BET) study, and from BET results the cobalt modified SnO2 has found to be higher surface area. These all-prepared sensors were applied for gas sensing results of NO2, LPG, CO and volatile organic compounds (VOC’S). The modified sensors found to be very effective at NO2 and VOC gas vapors with 80.23% and 69.13% gas response for cobalt modified SnO2 was observed. The tested gases NO2 and VOC found to be very selective modified sensors. Reusability and recycling results demonstrate that Co2+ doped SnO2 is very efficient, long time stable and reproducible sensor at NO2 and VOC gases at minimum gas concentration and moderate temperature.