Sensing mechanism of PbO doped tin oxide thick film for detection of LPG

Abstract

The present work studied PbO doped tin oxide (SnO2) based thick films using screen printing technique. We fabricated undoped and PbO-doped SnO2 thick film on an alumina substrate to be used as a sensor. There are three samples are prepared in the laboratory as S1 (SnO2 thick film), S2 (1 wt% PbO at firing temperature 800 °C), and S3 (1 wt% PbO at firing temperature 900 °C). The microstructural properties are observed using XRD data. XRD measurement reveals that the crystallite size in nanometric rage and it is ∼31.51 nm, 27.09 nm and 22.90 nm for S1, S2, and S3 respectively. The sensing performances of fabricated thick films are investigated at an operating temperature of 200 °C upon exposure to LPG concentration in the range of 0–5000 ppm. It is found that the maximum response of LPG at an operating temperature of 200 °C (5000 ppm) is 26 % and 20 % for S3 and S2 respectively. The response of sensor S3 is ∼2 times more sensitive to S1 and ∼1.47 time sensitive to S2 for LPG. Therefore the fabricated PbO–SnO2 sensor may use for appropriate detection of LPG and also observed the experimental result of the sensor are in good agreement with the predicted theoretical model.