Studies on gas sensing performance of (Ba0.8Sr0.2)(Sn0.8Ti0.2)O3 thick film resistors

Thick films of (Ba0.8Sr0.2)(Sn0.8Ti0.2)TiO3 (BSST) were prepared by screen-printing techniques. The surfaces of the films were modified by dipping them into an aqueous solution of copper chloride for different intervals of time, followed by firing at 550 °C for 30 min. The gas sensing performance of the unmodified and CuO-modified films was tested for various gases. The unmodified films showed response to ethanol and the CuO-modified films to SO2 gas. The surface modification, using dipping process, altered the adsorbate–adsorbent interactions, which gave the unusual sensitivity and selectivity effect. The gas response, selectivity, thermal stability, response and recovery time of the sensor were measured and presented. The role played by surface copper species in the gas sensing performance is discussed.