Humidity Sensor Based on High Proton Conductivity of Graphene Oxide

Abstract

This work explores the performance of graphene oxide (GO) as humidity sensor. GO was synthesized using modified Hummers and Offeman method and the sensing layer was characterized using optical microscope, scanning electron microscopy (SEM), atomic force microscopy (AFM), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The sensor devices were fabricated by drop-casting of GO on patterned gold electrodes on Si/SiO 2 substrate. GO based sensor was exposed to six different relative humidity (RH %) and the response of our sensor were found to be excellent due to large proton conduction. The sensor response varied from ~180 times (40% RH) to ~1200 times (88% RH). Our GO based humidity sensor also showed ultrafast response and recovery times with extremely good repeatability. Also, the role of functional groups in humidity sensing was explored by fabricating the sensor devices by thermally reducing GO for different time durations. We believe GO could potentially be used to develop new generation ultrasensitive humidity sensor.

Stretchable and Multimodal All Graphene Electronic Skin

“…The stable signal saturation behavior was monitored at three different RHs (40%, 60%, and 75%) as shown in Figure S3 in the Supporting Information, which is consistent with previous reports related with the GO humidity sensors. [ 37,38 ] In addition, the delamination issue of the GO layers from the channel ( Figure S4, Supporting Information) should be addressed because the GO was exposed to the outside environment. suggesting that charge transport in the rGO multilayer fi lms was governed by a 3D variable range hopping (VRH) model supplemented with parallel quantum tunneling.…”

The critical role of hydroxyl groups in water vapor sensing of graphene oxide

“…On comparison, these s res and s rec values are much higher than the values mentioned in previous reports. [39][40][41][42][43][44][45][46][47] However, we strongly believe that the mentioned s res and s rec values in the present case do not represent the actual surface reaction but are rather given by the gas mixing process of the designed sensor test experiment, as already described elsewhere. 48 This was already proven by the breath analysis experiment shown in Fig.…”

“…Although there are several reports on GO-based humidity sensors, 31,33,[40][41][42][43][44]47,49,50 the water molecule interaction mechanism with the GO surface has always been a controversial discussion in the scientic community. There is a lack of understanding of the GO surface nature and water adsorption, where some authors report GO to behave like an n-type material; 51 on the contrary, some recount it as a p-type material.…”

“…The formation of an ohmic GO-metal electrode interface and decrease in current values under a humid background were observed for all samples, which is in good agreement with the results of previous reports. [39][40][41][42][43][44] By forming an ohmic contact, the contribution of the GO-Au interface was eliminated and the obtained sensor response is purely given by the only the contribution of the GO-sensing layer in all cases, which makes the humidity sensing analysis uncomplicated. To further conrm the good GO/Au interface, SEM analysis was performed, and the SEM micrographs are shown in Fig.…”

Mechanical and Thermal Properties of Graphene over Composite Materials: A Technical Review

“…Likewise, GO film can be utilized as a convincing medium to limit essentialness. The range is about 15 to 1500 V. On account of the growing enthusiasm for unmanned air vehicles (UAVs), the imperativeness amassing the cutoff and load of battery reliably limit their flight length to help the power for UAVs, in which the essentialness is achieved from sun-based sheets attached to the outside of the structures [24,25]. In this structure, UAVs can support imperativeness free from any other individual in the midst of a flight mission.…”