Electrical conductivity of CdS films for gas sensing: Selectivity properties to alcoholic chains

Nanophased cadmium sulfide powder was synthesized with a simple route and characterized with thermal, structural and morphological analysis. Conductometric gas sensors based on thick films of synthesized CdS were fabricated by means of screen-printing technology and their sensing properties were tested on a selection of alcohols, aldehydes, ketones and other gaseous compounds. We found that, at working temperature of 300 °C, the CdS films show a strong selectivity vs alcohols, proving that they can efficiently detect alcohols in mixtures where aldehydes and other interferers are present. The response was found to be proportional to the length of the alcoholic chain, and a possible sensing mechanism that accounts for this property was proposed.