Abstract
This paper presents the relative humidity (RH) sensing response of a resistive sensor employing sensing layers based on a ternary nanocomposite comprising graphene oxide-oxidized carbon nanohorns-polyvinylpyrrolidone (GO-CNHox–PVP), at 1/1/1, 1/2/1, and 1/3/1 w/w/w mass ratios. The sensing structure is composed of a silicon substrate, a SiO2 layer, and interdigitated transducers (IDT) electrodes, on which the sensing layer is deposited via the drop-casting method. The morphology and the composition of the sensing layers are investigated through scanning electron microscopy (SEM) and RAMAN spectroscopy. The RH sensing capability of each carbonaceous nanocomposite-based thin film was analyzed by applying a current between the two electrodes and by measuring the voltage difference when varying the RH from 0% to 100% in humid nitrogen. The sensors have a room temperature response comparable to that of a commercial humidity sensor and are characterized by a rapid response, excellent linearity, good sensitivity, and recovery time. The manufactured sensing devices’ transfer functions were established, and we extracted the response and recovery times. While the structures with GO/CNHox/PVP at 1/1/1 ratio (w/w/w) had the best performance in terms of relative sensibility, response time, and recovery time, the sensors employing the GO/CNHox/PVP nanocomposite at the 1/2/1 ratio (w/w/w) had the best linearity. Moreover, the ternary mixture proved to have much better sensing properties compared to CNHox and CNHox-PVP-based sensing layers in terms of sensitivity and linearity. Each component of the ternary nanocomposites’ functional role is explained based on their physical and chemical properties. We analyzed the potential mechanism associated with the sensors’ response; among these, the effect of the p-type semiconductor behavior of CNHox and GO, correlated with swelling of the PVP, was dominant and led to increased resistance of the sensing layer.
Highlights
For the first time to our knowledge, the results demonstrate the relative humidity sensing capabilities of a Graphene oxide (GO)-CNHox-hydrophilic polymer nanocomposite at different ratios when used in a resistive humidity sensor operating at a room temperature
This paper reports the relative humidity (RH) sensing response of a resistive sensor employing a sensing layer based on a ternary nanocomposite comprising graphene oxide-oxidized carbon nanohorns-polyvinylpirrolidone (GO-CNHox-polyvinylpy rrolidone (PVP)), at 1/1/1, 1/2/1, and 1/3/1 w/w/w ratio
The key role of each component of the ternary nanocomposites was explained based on their chemical structure and their physical and chemical properties
Summary
Among the types of devices used in the control and monitoring of humidity-capacitive [4], gravimetric [5], thermal conductivity sensors [6], and optical fiber [7], the resistive sensors are an attractive option. Their simplicity in construction, interchangeability, small size, low cost, long-term stability, and excellent sensitivity [8] makes the resistive sensors perfect candidates for humidity measurements. The resistive humidity sensors’ performance, in terms of aspects such as sensitivity, response time, and recovery time, is strongly related to the sensing materials’ properties [9]. A diversity of materials has been studied as the sensing layer within the design of humidity sensors: metal oxides semiconductors [10,11], polyelectrolytes [12,13], conducting polymers like poly(3,4-ethylenedioxythiophene–poly(styrene-sulfonate) [14] or polyaniline [15], and perovskites [16,17]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
