Boosting stability of electronic multi-gas sensors

Conventional electronic gas sensors are designed with a single-output response (e.g. resistance, current). Under variable ambient conditions such sensors suffer from fluctuations (drift) of their response because single-output sensor designs mathematically do not allow for drift correction. We break this status quo by developing a new generation of gas sensors, known as multivariable sensors with several independent responses. Previously, we showed that individual multivariable gas sensors quantify several gases and reject interferences. Here we show that such multivariable gas sensors have the ability for self-correction for sensor drift. Our multivariable gas sensors described here operate in the radio-frequency (RF) portion of the electromagnetic spectrum and utilize dielectric excitation of semiconducting metal oxide materials on the shoulder of their dielectric relaxation peak. We self-correct for the baseline drift by sensor operation at more than one RF frequency. Our approach for the drift self-correction should allow implementations of gas sensors in diverse applications that cannot afford weekly, monthly, or quarterly periodic maintenance, typical of traditional analytical instruments.