Ternary Holey Carbon-Based Nanohybrid for Resistive Relative Humidity Sensor

This paper reports on the relative humidity (RH) sensing response of a resistive sensor employing a ternary nanohybrid sensing layer comprising holey carbon nanohorns (CNHox), ZnO, and polyvinylpyrrolidone (PVP) at 5/2/1 w/w/w ratio. The sensing device includes a silicon substrate, a SiO
2
layer, and two interdigitated electrodes (IDE). The sensing film is deposited via the drop-casting method on the sensing structure. The sensing layer’s morphology and composition are investigated through Scanning Electron Microscopy (SEM) and Raman spectroscopy. The resistance of the sensing layer increases while varying RH in the 0%-100% range, with increased sensitivity for RH > 60% and a response time (t
r
) comparable to that of a commercially available, state-of-the-art, capacitive RH sensor. The repeatability is assessed by performing 5 full sensing cycles. Several sensing mechanisms are considered and discussed, given the experimental results.