Development of Highly Sensitive and Stable Surface Acoustic Wave‐Based Hydrogen Sensor and Its Interface Electronics

Abstract

cause significant damage to humans. ≈4%-75% of the hydrogen content in air is combustible, therefore real-time monitoring of hydrogen leakages is essential to prevent potentially catastrophic events in practical applications. As previously reported in the literature, the hydrogen is generated in transformer insulating oil due to local heating, corona, and arcing. [1][2][3] Gas chromatography and photoacoustic spectroscopy are the typically used methods to measure the concentration of hydrogen leaking out through a ultrafine porous filter from the insulating oil near the drain of a transformer, but the sensor systems involved are bulky, too complex, expensive, and a significant amount of time is required to obtain the final results. Various types of hydrogen sensors have been reported in the literature with different operation mechanisms and sensing materials, including resistance type, [4][5] optical fiber, [6][7][8] electrochemical-based type, [9] and methods using surface acoustic wave (SAW) technology. [10][11][12][13] Most available resistive types of hydrogen sensors usually operate at high temperatures which precludes their commercialization. The high operating temperature of resistive based hydrogen sensors can also lead to the explosive hazards and energy consumption. Among various types of gas sensors, in particular, SAW-based hydrogen gas sensors have drawn attention owing to their high sensitivity, room temperature operation, stability, and low minimum detection level. The sensing mechanism of the SAW sensor is based on the adsorption of target gas molecules on the surface of sensing materials which induces changes in the mass (mass loading), conductivity (electric loading), and elasticity (elastic loading) of sensing film deposited in the propagation path. Any changes, such as mass, resistance, and elastic properties of sensing material lead to modification of SAW propagation properties, resulting in a frequency shift of SAW sensors. Previous studies have shown that mass, electric, and elastic loading are the three factors likely to contribute to the frequency shift of SAW-based sensors. [14] Moreover, several factors may concurrently contribute to the frequency shift of SAW-based sensors. Therefore, it is important to study the contribution of each factor to better understand the detection mechanism for the production of high performance SAW A surface acoustic wave (SAW)-based hydrogen sensor and its corresponding interface electronics have been developed to measure the hydrogen concentration in air at room temperature. Two SAW delay lines with center frequencies of 284 and 284.3 MHz are employed for the sensor system to eliminate any environmental disturbances emerging from temperature and humidity variations on a sensor output. A beehive-configured and Cu-doped SnO 2 nanostructure is used as a hydrogen-sensitive material to have a high surface to volume ratio, high sensitivity, and selectivity for the target hydrogen. The smallest frequency difference detectable in our sensor system including oscil...

Synthesis and Characterization of High‐Quality Ta2O5 Nanoparticles for Highly Selective SAW‐Based DUV Sensor and Corona Detection Application

“…In accordance with our previous research, [38] the sensing characteristics of the sensor were investigated using our newly developed interface electronics, which can compensate environmental interference such as humidity and temperature effects (Figure S4, Supporting Information). The sensor underwent various treatments, including annealing at different temperatures and adjusting solution concentrations, to optimize performance.…”

“…A detailed description of the simulation was described in detail in the previous paper, so this omit it here. [20,38] Based on the optimally designed parameters, a SAW device was fabricated. First, a 4-inch LN substrate was subjected to a coating procedure involving spin-coating a 1-μm thick negative photoresist (PR, AZ 5214) and patterning the photoresist through a UV lithography process.…”

Comprehensive Review of Hydrogen Leakage in Relation to Fuel Cell Vehicles and Hydrogen Refueling Stations: Status, Challenges, and Future Prospects

“…Acoustic detection technology is based on the principle of propagation and reception of acoustic waves, and the detection and quantitative analysis of leaks are achieved by measuring the acoustic wave signals generated by hydrogen leaks . As shown in Figure , an acoustic detection device typically consists of an acoustic surface wave transmitter, an acoustic surface wave receiver, and a specific hydrogen-sensitive film .…”

Development of Highly Stable and Sensitive SAW UV Sensor Based on Ta2O5 Coated 1D ZnO/SnO2 Core–Shell Nanostructures

“…The details of the SAW sensor measurement system including FPGA and PC were detailed in the previous study. [28]…”