Abstract
Arrays of broadly cross-reactive sensors are key elements of smart, self-training sensing systems. Chemically sensitive resistors and quartz-crystal microbalance (QCM) sensors are attractive for sensing applications that involve detection and classification of volatile organic compounds (VOCs) in the gas phase. Polycyclic aromatic hydrocarbon (PAH) derivatives as sensing materials can provide good sensitivity and robust selectivity towards different polar and nonpolar VOCs, while being quite tolerant to large humidity variations. Here, we present a comparative study of chemiresistor and QCM arrays based on a set of custom-designed PAH derivatives having either purely nonpolar coronas or alternating nonpolar and strongly polar side chain termination. The arrays were exposed to various concentrations of representative polar and nonpolar VOCs under extremely varying humidity conditions (5-80% RH). The sensor arrays' classification ability of VOC polarity, chemical class and compound separation was explained in terms of the sensing characteristics of the constituent sensors and their interaction with the VOCs. The results presented here contribute to the development of novel versatile and cost-effective real-world VOC sensing platforms.
Highlights
Arrays of broadly cross-reactive sensors have received significant attention as key elements of smart, self-training sensing systems.[1,2,3,4,5] These arrays could meet the growing demand for rapid and flexible online detection of a wide range of chemical and biological agents in different branches of industry, homeland security,[5], diagnostics[1,2,3,4,5], environmental monitoring,[5, 7, 8] and medical
The principle component analysis (PCA) plots ascribed to the six Polycyclic aromatic hydrocarbon (PAH)-coated quartz-crystal microbalance (QCM) sensors in array 2 show that the data points of the polar volatile organic compounds (VOCs) under atmosphere of 5% relative humidity (RH)
We have presented a comparative study of the VOCs sensing performance of six customdesigned PAH derivatives with different types of side chains as sensing elements in arrays of chemiresistors and QCM sensors
Summary
The heat-map representation in Figure 2 summarizes the relative resistance changes for the six studied PAH derivatives to polar and nonpolar VOCs at concentrations between pa/po = 0.05 and pa/po = 0.2 and under low (5%), intermediate (40%) and high (80%) background RH levels. The PCA plots ascribed to the six PAH-coated QCM sensors in array 2 (see side panels of Figure 4b) show that the data points of the polar VOCs under atmosphere of 5% RH
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