Chemically synthesized PbS Nano particulate thin films for a rapid NO₂ gas sensor

Rapid NO₂ gas sensor has been developed based on PbS nanoparticulate thin films synthesized by Successive Ionic Layer Adsorption and Reaction (SILAR) method at different precursor concentrations. The structural and morphological properties were investigated by means of X-ray diffraction and field emission scanning electron microscope. NO₂ gas sensing properties of PbS thin films deposited at different concentrations were tested. PbS film with 0.25 M precursor concentration showed the highest sensitivity. In order to optimize the operating temperature, the sensitivity of the sensor to 50 ppm NO₂ gas was measured at different operating temperatures, from 50 to 200 ^°C. The gas sensitivity increased with an increase in operating temperature and achieved the maximum value at 150 ^°C, followed by a decrease in sensitivity with further increase of the operating temperature. The sensitivity was about 35 % for 50 ppm NO₂ at 150 ^°C with rapid response time of 6 s. T90 and T10 recovery time was 97 s at this gas concentration.