High-Performance Wireless Ammonia Gas Sensors Based on Reduced Graphene Oxide and Nano-Silver Ink Hybrid Material Loaded on a Patch Antenna

Abstract

Reduced graphene oxide (rGO) has been studied as a resistive ammonia gas sensor at room temperature. The sensitive hybrid material composed of rGO and nano-silver ink (Ag-ink) was loaded on a microstrip patch antenna to realize high-performance wireless ammonia sensors. The material was investigated using scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). Firstly, interdigital electrodes (IDEs) printed on the polyethylene terephthalate (PET) by direct printing were employed to measure the variation of resistance of the sensitive material with the ammonia concentration. The results indicated the response of sensor varied from 4.25% to 14.7% under 15–200 ppm ammonia concentrations. Furthermore, the hybrid material was loaded on a microstrip patch antenna fabricated by a conventional printed circuit board (PCB) process, and a 10 MHz frequency shift of the sensor antenna could be observed for 200 ppm ammonia gas. Finally, the wireless sensing property of the sensor antenna was successfully tested using the same emitted antenna outside the gas chamber with a high gain of 5.48 dBi, and an increased reflection magnitude of the emitted antenna due to the frequency mismatch of the sensor antenna was observed. Therefore, wireless ammonia gas sensors loaded on a patch antenna have significant application prospects in the field of Internet of Things (IoTs).

Year 2020: A Snapshot of the Last Progress in Flexible Printed Gas Sensors

“…The oxygenated functional groups also offer different possibilities for the surface functionalization with noble metals, metal oxides and conductive polymers [91]. An example of flexible ammonia sensor based on rGO and nano-Ag ink deposited through inkjet printing to a PET substrate is reported in [50] and shown in Figure 9. The sensor was tested to 15 ppm, 50 ppm, 100 ppm, and 200 ppm of NH3 at room temperature showing responses of 4.25%, 6.1%, 10.08%, and 14.7%, respectively (see Figure 10).…”

“…(a) Current-voltage (I-V) curves for the coated IDEs with rGO/Ag-ink; (b) dynamic response of the IDEs sensors to different concentrations of NH 3 at room temperature [50]…”

Antenna-Based Popup Vapor Sensor Guided by Controlled Compressive Buckling

“…These values are the average performance of three sensor samples with PDMS thickness of 0.4 mm. Measurements in Fig 9(d) show that the minimum detectable vapor concentration is 36 ppm which corresponds to 180 MHz frequency shift and once the sensor is activated, it can detect vapor at the minimum rate of 0.6 MHz/ ppm (between low and high concentrations) which is better than the values reported in the recent publications [4], [10], [12], [13]. This rate value is greater (1.1 MHz/ppm) for low vapor concentrations (lower than 300 ppm) which is attributed to the saturation effect in the PDMS substrate.…”

“…To date various attempts have been made to integrate smart materials into antenna designs for wireless gas sensing [4]- [12]. For example, changes to the conductivity of carbon nanotubes or graphene integrated in an antenna, in the presence of chemical vapors led to a shift in resonant frequency [4]- [10]. Furthermore, the variation in optical, electrical and chemical properties of customized nanoparticle dispersion inks with exposure to a particular gas to tune antenna responses have been exploited.…”

Green syntheses of silver nanoparticle decorated reduced graphene oxide using l-methionine as a reducing and stabilizing agent for enhanced catalytic hydrogenation of 4-nitrophenol and antibacterial activity

“…19,20 Graphene is a two-dimensional sp 2 -hybridized carbon material, due to its excellent charge transport mobility, large specic surface area, high electrocatalytic activity, and low cost currently attract the huge interest for the wide range of application. [21][22][23] The graphene-Ag nanocomposites have been exploited for multifunctional applications, including catalysis, 24 sensor, 25 imaging, 26,27 and energy storage. 28 Hence, in order to explore the potential application, it is of prime importance to the synthesis of these nanocomposite materials through a facile, large-scale production with quality and environmentally friendly approaches.…”