Recent Advances in Graphene-Based Humidity Sensors

Abstract

Humidity sensors are a common, but important type of sensors in our daily life and industrial processing. Graphene and graphene-based materials have shown great potential for detecting humidity due to their ultrahigh specific surface areas, extremely high electron mobility at room temperature, and low electrical noise due to the quality of its crystal lattice and its very high electrical conductivity. However, there are still no specific reviews on the progresses of graphene-based humidity sensors. This review focuses on the recent advances in graphene-based humidity sensors, starting from an introduction on the preparation and properties of graphene materials and the sensing mechanisms of seven types of commonly studied graphene-based humidity sensors, and mainly summarizes the recent advances in the preparation and performance of humidity sensors based on pristine graphene, graphene oxide, reduced graphene oxide, graphene quantum dots, and a wide variety of graphene based composite materials, including chemical modification, polymer, metal, metal oxide, and other 2D materials. The remaining challenges along with future trends in high-performance graphene-based humidity sensors are also discussed.

Graphene Oxide Papers in Nanogenerators for Self-Powered Humidity Sensing by Finger Tapping

“…Humidity sensing plays a key role in domestic control, medical care, agricultural moisture monitoring, and industrial applications 19 . GO-based humidity sensors have been widely under attention due to notable properties such as simple, low-cost, and large-scale preparation of GO material along with high proton-conductivity in exposure to water molecules 20 . GO humidity sensors operate on the basis of detecting the variation of impedance or capacitance due to the inclination of the water molecules to adsorb on the surface of GO [21][22][23][24][25][26] .…”

“…On the other hand, the capacitive sensors detect the humidity by measuring the capacitance change which consists of the interdigitated conductive electrodes and GO-based sensing materials as the dielectric connected to the LCR meter. For practical usage of a humidity sensor, not only the sensing performance such as fast response and high sensitivity, but also low cost, easy fabrication, facile integration, and good flexibility are significant factors, which are generally depends on the sensing materials and fabrication methods 20 . In spite of various investigations demonstrated the effect of utilization of polymers 27,28 , metal oxides [29][30][31] and 2D materials 32,33 alongside GO, with the purpose of enhancement of humidity sensing, the fabrication method has become relatively more sophisticated.…”

Recent advances in cellulose-based membranes for their sensing applications

“…(Fu et al 2019 ; Zhu et al 2019a , b ; Li et al 2017a , b , c ; Amin 2015 ; Duong et al 2018 ; Hittini et al 2020 ; Tang et al 2019 ). The excellent sensing performances can be obtained by introducing metal nanowires, metal nanoparticles, carbon dots, quantum dots, carbon nanotubes, fluorophores, organic dyes and antigen-antibodies into cellulose membranes through physical-chemical methods (Lou et al 2020 ; Zhang et al 2019a , b , c ; Jiang et al 2020a , b ; Li et al 2017a , b , c ; Lv et al 2019a , b ; Shankar et al 2020 ).…”

Ultrafast‐Response Humidity Sensor with High Humidity Durability Based on a Freestanding Film of Graphene Oxide Supramolecular

“…As a 2D carbon material, graphene oxide (GO) with oxygen‐containing functional groups on the surface is a promising candidate for humidity sensor . GO sheets are advantageous for providing large surface reaction sites due to the large surface‐to‐volume ratio and unique 2D structure, so GO‐based sensors could have fast response for adsorption and desorption of water molecules . For example, Borini et al reported an ultrafast‐response humidity sensing film by spraying GO on the polyethylene naphthalate substrate with silver interdigitated electrode .…”