High performance graphene oxide-based humidity sensor integrated on a photonic crystal cavity

Abstract

We report a high performance relative humidity (RH) microsensor by coating a few-layer graphene oxide (GO) flake over a photonic crystal (PC) cavity. Since the GO layer has a high water-activity and interacts with the evanescent cavity mode strongly, the exposure of GO-PC cavity in varied humidity levels results in significant resonant wavelength shifts, showing a slope of 0.68 nm/%RH in the range of 60%∼85% RH. By interrogating the power variation of the cavity reflection, the microsensor presents an ultrahigh sensitivity exceeding 3.9 dB/%RH. Relying on the unimpeded permeation of water molecules through the GO interlayers and microscale distribution of the cavity mode, the integrated sensor has a response time less than 100 ms, which promises successful measurements of human breathing. Combining with the ease of fabrication, this high performance RH sensor has potential applications requiring optical access, device compactness, and fast dynamic response.Detection of relative humidity (RH) is extremely important in environment monitoring, medicine and indoor air quality control, and chemical industry processing. Two-dimensional (2D) materials, including graphene, transition metal dichalcogenides, and phosphorene, have shown great promises for RH sensing due to their high surface-tovolume ratio, low noise and sensitivity of electronic properties to the surrounding variations [1][2][3]. Here, we report high performance 2D material-based RH sensing could be optically accessed as well by integrating the active material * Electronic address:

Graphene oxide-deposited tilted fiber grating for ultrafast humidity sensing and human breath monitoring

“…One of the paths was inserted into the pure water to generate the saturated humid gas. Then, the two paths were mixed with another Y-tube to the inlet of the chamber, thus the RH level inside could be controlled by individually adjustable flow rates [24,37].…”

“…More importantly, there are rich oxygen-coating groups between layers for interacting with water molecules, such as hydrophilic hydroxyl, epoxy, and carboxylic groups [1]. In addition, these groups provide a channel for superpermeability to water molecules, which could facilitate their fast interaction processes between water molecules and GO layers, and thus can be developed in humidity sensing devices [14,[22][23][24][25][26].…”

Silicon as a ubiquitous contaminant in graphene derivatives with significant impact on device performance

“…Oxygen-containing functional groups on the hydrophilic surface of GO provide a high potential to adsorb water molecules 41 . Therefore, GO-based relative humidity (RH) sensors have shown great promise in this respect 42 – 44 . However, the detection range and moisture uptake reported so far, although promising, represent just an incremental improvement over existing technologies.…”

Rapid preparation of a Nafion/Ag NW composite film and its humidity sensing effect

“…Many creative methods based on different mechanisms, including optical, gravimetric, capacitive, resistive, piezoresistive, and magnetoelastic, have been proposed for humidity sensing applications. [1][2][3][4][5][6][7] During these current transduction techniques, there is a requirement of auxiliary facilities to detect and amplify the signal change in their electrical parameters, some of which are seriously affected by the environment and even need signal ltration so as to obtain more stable and accurate data. Therefore, there is a strong need to explore a passive and anti-interference humidity sensor.…”