Printed oxygen gas sensor using copper-DTDTPA solid electrolyte.

We present a new method for the rapid and cost-effective fabrication of solid electrolyte-based printed potentiometric oxygen sensors working at ambient temperature using Cu-dithiolated diethylene triamine pentaacetic acid complex molecules (Cu-DTDTPA) adsorbed on Grade-1 laboratory filter paper and subsequent 3-D printing of interdigitated electrodes employing silver/silver chloride ink. The decrease in conductivity with time and frequency-dependent impedance response confirms the filter paper adsorbed Cu-DTDTPA as a solid electrolyte. A plausible structure of the Cu-DTDTPA solid electrolyte and its mechanism of reaction with oxygen are presented. A maximum sensitivity of 0.052 mV per %O2, the maximum response time of 1.15 s per %O2, a wide measurement output ranging from 14.55 mV to 17.25 mV for 20%-90% of O2 concentration, a maximum standard deviation of 0.12 mV in output voltage, almost similar trends of the response on temperature, humidity variations and ageing and high selectivity establish the sensor for use in medical ventilator applications, specifically in the COVID19 pandemic.