Cadmium detection by polyaniline-zinc oxide composite thin-film sensor

Abstract

The conventional analytical techniques for detection of cadmium (Cd) requires expensive equipment and skilled operators. Although sensor technology developed nowadays are miniature and user-friendly, most of them are high in fabrication costing and complex in preparing its sensing material. As such, composite of polyaniline (PANI) and zinc oxide (ZnO) are selected to fabricate a simpler thin-film sensor with lower costing for Cd detection. Cd concentration is varied in the range from 1 ppm to 100 ppm are used to analyze the sensitivity of the sensor, and the result shows that a higher Cd concentration leads to a higher voltage reading, in the range of 18.16 mV to 65.10 mV. This is attributed to the mechanism of Cd2+ ions adsorption on the surface of ZnO, which induces a change in conductivity. Besides, PANI functions as a conducting polymer that stabilizes ZnO to enhance the detection performance.