Method of detecting volatile organic compounds

A method of using a sensor element, the method comprising the steps:

• a) providing a sensor element, the sensor element comprising a reflective conductive electrode, a semi-reflective conductive electrode, and a detection layer comprising dielectric optically-transmissive microporous material sandwiched between the reflective conductive electrode and the semi-reflective conductive electrode, wherein at least one of the semi-reflective conductive electrode or the reflective conductive electrode is permeable to an analyte vapor;
• b) determining a baseline capacitance and a baseline reflection spectrum for the sensor element at a temperature and humidity level;
• c) obtaining a capacitance of the sensor element while exposed to the analyte vapor to obtain a measured capacitance;
• d) obtaining a reflection spectrum of the sensor element while exposed to an analyte vapor to obtain a measured reflection spectrum comprising a spectral feature;
• e) obtaining a true capacitance of the sensor element, wherein the true capacitance is equal to the measured capacitance minus a baseline capacitance of the sensor element;
• f) obtaining a wavelength shift of the spectral feature, wherein the wavelength shift of the spectral feature equals difference in the wavelength of the spectral feature in the baseline reflection spectrum and the measured reflection spectrum;
• g) comparing a pairing of the true capacitance and the wavelength shift to a reference library, wherein the reference library comprises reference correlations between the wavelength shift and the true capacitance, or at least one derivative thereof, for a plurality of reference analyte vapors;
• and
• h) determining at least one of the chemical class or identity of the analyte vapor based on the comparison of step g),
• wherein steps d) and e) are simultaneous.