Toward On-Chip Multisensor Arrays for Selective Methanol and Ethanol Detection at Room Temperature: Capitalizing the Graphene Carbonylation

Abstract

The artificial olfaction units (or e-noses) capable of room-temperature operation are highly demanded to meet the requests of society in numerous vital applications and developing Internet-of-Things. Derivatized 2D crystals are considered as sensing elements of choice in this regard, unlocking the potential of the advanced e-nose technologies limited by the current semiconductor technologies. Herein, we consider fabrication and gas-sensing properties of On-chip multisensor arrays based on a hole-matrixed carbonylated (C-ny) graphene film with a gradually changed thickness and concentration of ketone groups of up to 12.5 at.%. The enhanced chemiresistive response of C-ny graphene toward methanol and ethanol, of hundred ppm concentration when mixing with air to match permissible exposure OSHA limits, at room-temperature operation is signified. Following thorough characterization via core-level techniques and density functional theory, the predominant role of the C-ny graphene-perforated structure and abundance of ketone groups in advancing the chemiresistive effect is established. Advancing practice applications, selective discrimination of the studied alcohols is approached by linear discriminant analysis employing a multisensor array’s vector signal, and the fabricated chip’s long-term performance is shown.

Rationalizing Graphene–ZnO Composites for Gas Sensing via Functionalization with Amines

“…Extrapolating the acquired SNR(C) towards the cap of SNR = 3, corresponding to the minimum practical level of signal detection, the limit of detection (LOD) was determined to be 5.1 ppm, 3.6 ppm, and 1.3 ppm for NH 3 , C 2 H 5 OH, and H 2 O, respectively. These values are among the most commonly reported for state-of-the-art graphene-based gas-sensing devices (Supplementary Materials, Section S6) and already fit almost all practical demands for the detection of ammonia and alcohols [7,8,[14][15][16]18,27,[79][80][81]. To further manifest the operation of the fabricated multisensor chips under various conditions, the chemiresistive response of the on-chip sensor arrays composed of AmG and Am-ZnO layers toward NH3 and C2H5OH mixed with humid air was recorded and examined.…”

“…AmG and Am-ZnO layers were placed over the on-chip multisensor arrays by spray coating according to protocols described elsewhere [27,28]. Both chips were cut from Si/SiO 2 substrate at 9 × 10 mm 2 in size, to be metalized with an array of 39 co-planar strip Pt (in the case of AmG) or Au (in the case of Am-ZnO) electrodes (50 µm wide, with 50 µm gaps) via magnetron sputtering (Emitech K575X, Ashford, Kent, UK) and photolithography patterning.…”

“…These particular analytes were chosen because, on the one hand, they are among the most representative test gases to compare the performance of the developed multisensor chips with the published data and, on the other hand, their detection is highly important in industry and ecological monitoring. In the case of the dry air, the humidity level was maintained below 200 ppm, with other gaseous contaminants ensured with a dry air generator (PG14L, Peak Scientific, Glasgow, UK) at levels below 0.1 ppm [27].…”

A Dual-Channel MoS2-Based Selective Gas Sensor for Volatile Organic Compounds

“…al. [16], with large area flakes or wafer-scale MoS 2 grown by chemical vapour deposition. Furthermore, the layer-thickness-dependent sensitivity can be explored in future studies.…”

“…Beyond these materials, two-dimensional (2D) materials have emerged as promising candidates for sensing applications in recent years due to their high surface-to-volume ratio and the presence of dangling bonds on their surfaces and edges, making them ideal materials for physisorptionand chemisorption-based sensors. Apart from graphene [14][15][16], there are a variety of 2D semiconductors used for gas sensing [17], such as molybdenum disulfide (MoS 2 ) [18,19], molybdenum diselenide (MoSe 2 ) [20], molybdenum ditelluride (MoTe 2 ) [21], tungsten disulfide (WS 2 ) [22], tungsten diselenide (WSe 2 ) [23], and germanium selenide (GeSe) [24]. Suh et al showed that a pristine MoS 2 -based sensor at 110 • C has a response to 500 ppm ethanol gas with 25% responsivity [25], and Chen et al reported that a MoS 2 gas sensor detected 40 ppm ethanol, acetone, toluene, and hexane gases with responses of 11%, 12%, 6%, and 4%, respectively [26].…”