GC-like Graphene-Coated Quartz Crystal Microbalance Sensor with Microcolumns

Abstract

Many research groups have been interested in the quartz crystal microbalance (QCM)-based gas sensors due to their superb sensitivity originated from direct mass sensing at the ng level. Despite such high sensitivities observed from QCM sensors, their ability to identify gas compounds still needs to be enhanced. Herein, we report a highly facile method that utilizes microcolumns integrated on a QCM gas-responsive system with enhanced chemical selectivity for sensing and ability to identify volatile organic compound single gases. Graphene oxide (GO) flakes are coated on the QCM electrode to substantially increase the adsorption of gas molecules, and periodic polydimethylsiloxane microcolumns with micrometer-scale width and height were installed on the GO-coated QCM electrode. The observed frequency shifts upon sensing of various single gas molecules (such as ethanol, acetone, hexane, etc.) can be analyzed accurately using a simple exponential model. The QCM sensor system with and without the microcolumn both exhibited high detection response values above 50 ng/cm2 for sensing of the gases. Notably, the QCM sensor equipped with the microcolumn features gas identification ability, which is observed as distinct diverging behavior of time constants upon detection of different gases caused by the difference in diffusional transfer of molecules through the microcolumns. For example, the difference in the calculated time constant between ethanol and acetone increased from 22.6 to 92.1 s after installation of the microcolumn. This approach provides an easy and efficient method for identification of single gases, and it may be applied in various advanced sensor systems to enhance their gas selectivity.

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“…They are effective analytical devices [49][50][51]. Compared to traditional methods, they provide label-free and real-time detection, easy use with modern technologies, portable size, high sensitivity, low cost, and basic data analysis [52][53][54].…”

“…They are effective analytical devices[49][50][51]. Compared to traditional methods, they provide label-free and real-time detection, easy use with modern technologies, portable size, high sensitivity, low cost, and basic data analysis[52][53][54].It is very important to use accurate and timely detection methods to prevent the progression of a disease and stop the chain of transmission with early diagnosis. Traditional assays are often time-consuming and expensive.…”

Nanoporous Functionalized WS2/MWCNTs Nanocomposite for Trimethylamine Detection Based on Quartz Crystal Microbalance Gas Sensor

“…Various sensing materials were modified on the surface of QCM electrodes, the dimension, size, and morphology of which determine the adsorption between the sensors and gas molecules . For example, Son et al reported a graphene oxide coated QCM gas sensor with micrometer-scale column-installed for sensing and identifying different gases . Because of the difference in diffusional transfer of gas molecules through the microcolumns, the QCM sensor could identify ethanol, acetone, and hexane.…”

Silicon Nanowire Arrays with Nitrogen-Doped Graphene Quantum Dots for Photodetectors

“…Here, GQDs find a significant research interest in various optoelectronic applications due to their tunable electro-optical properties and nontoxicity making it an alternative candidate for replacing inorganic QDs. 28,29 The unique optical properties of GQDs make them a favorable material for high gain photodetection materials in a broad wavelength range particularly in the UV range. 30 The UV−visible photodetector has been designed using GQD incorporated ZnO nanorods.…”

“…Recently because of the high market cost of inorganic QDs and due to their high toxicity, industrial use of these materials has been restricted. Here, GQDs find a significant research interest in various optoelectronic applications due to their tunable electro-optical properties and nontoxicity making it an alternative candidate for replacing inorganic QDs. , The unique optical properties of GQDs make them a favorable material for high gain photodetection materials in a broad wavelength range particularly in the UV range . The UV–visible photodetector has been designed using GQD incorporated ZnO nanorods. , Studies reported that 80% EQE was obtained within a broad wavelength range in a photodetector based on a graphene quantum dot layer sandwiched between graphene sheets .…”