Resistive humidity sensor based on vanadium complex films

A resistive-type relative humidity (RH) sensor based on vanadium complex (VO2 (3-fl)) film is reported in this study. Gold electrodes were deposited on the glass substrates in a co-planar structure. A thin film of vanadium complex was coated as a humidity-sensing material on the top of the pre-patterned electrodes. The humidity-sensing principle of the sensor was based on the conductivity change of coated sensing element upon adsorption/desorption of water vapor. The resistance of the humidity sensor measured at 1 kHz decreased linearly with increasing the humidity in the range of 35%-70% RH. The overall resistance of the sensor decreases 11 times. An equivalent circuit for the VO2 (3-fl) based resistive-type humidity sensor was developed. The properties of the sensor studied in this work make it beneficial for use in the instruments for environmental monitoring of humidity.