Conductivity testing with varied RH% of POM films

Raw data for the paper submitted 'Post transition metal substituted Keggin POMs as thin film chemiresistive sensors for H₂O and CO₂ detection'

Current-voltage (IV) measurements were performed between -2 V and 2 V with a step size of 0.1 V and scan rate of 1 Vs^-1. Measurements were taken in the forward and reverse direction. The resistance of the device was calculated through the inverse slope of the resultant linear plot, from which the conductivity was calculated using equation 1.¹ The length and width of the channel were measured with an optical microscope.

Where σ: conductivity, ρ: resistivity, R: resistance in ohms, L: length in metres, A: the area in m², V: voltage, and I: current.

Samples were measured in a humidity-controlled environment with a purpose-built holder and printed circuit board (PCB), coupled with a QTenki humidity sensor and temperature probe (Dracal Technologies). The appropriate gas (either air, N₂, or CO₂ only) was passed through the water bubbler before passing through the sample container. The container was purged for 15 minutes with the respective gas prior to each measurement. The flow rate was adjusted to control the humidity. Four repeat measurements were taken for each POM electrode.