Effect of Pt electrodes in cerium oxide semiconductor-type oxygen sensors evaluated using alternating current

We developed a cerium oxide thick film semiconducting sensor for measuring the oxygen concentration in simulated exhaled gas. The oxygen sensor characteristics were investigated using simulated exhaled gas con-taining 15 % oxygen, 5 % carbon dioxide, and 80 % nitrogen. The sensor is required to accurately measure oxygen concentrations in the 15 % (typical of exhaled breath) to 21 % (atmospheric oxygen concentration) range. Since temporary resistance is widely known to drift when a direct current (DC) voltage is applied during sensing, we used alternating current (AC) in this study. The results suggest that changes in sensor resistance in response to simulated exhaled gas depend on the frequency of the AC signal. Furthermore, change in resistance depends on the morphology of the platinum electrode at a given frequency.

Automated summary

The study developed a cerium oxide thick film semiconductor sensor for measuring oxygen concentration in simulated exhaled gas, finding that sensor response to the gas depends on the frequency of the AC signal and the morphology of the platinum electrode at a given frequency.