Single-Nanobelt Electronic Nose: Engineering and Tests of the Simplest Analytical Element

Abstract

Electronic instruments mimicking the mammalian olfactory system are often referred to as "electronic noses" (E-noses). Thanks to recent nanotechnology breakthroughs the fabrication of mesoscopic and even nanoscopic E-noses is now feasible in the size domain where miniaturization of the microanalytical systems encounters principal limitations. Here we describe probably the simplest and yet fully functioning E-nose made of an individual single-crystal metal oxide quasi-1D nanobelt. The nanobelt was indexed with a number of electrodes in a way that each segment of the nanobelt between two electrodes defines an individual sensing elemental "receptor" of the array. The required diversity of the sensing elements is "encoded" in the nanobelt morphology via longitudinal width variations of the nanobelt realized during its growth and via functionalization of some of the segments with Pd catalyst. The proposed approach represents the combined bottom-up/top-down technologically viable route to develop robust and sensitive analytical systems scalable down to submicrometer dimensions.

Self-activated ultrahigh chemosensitivity of oxide thin film nanostructures for transparent sensors

“…Smart sensors, offering real-time analysis of gaseous chemical analytes, are essentials for environmental emissions monitoring, fossil fuel combustion control, medical diagnosis, artificial olfaction and homeland security123456789. Simplicity in operation, low cost, flexibility in production and small size constitute the main advantages of chemoresistive-type semiconductor chemical sensors based on metal oxides over electrochemical, optical, acoustic and other types of chemical sensors101112131415.…”

Chemoresistive materials for electronic nose: Progress, perspectives, and challenges

“…As a method for improving the selectivity of a single material sensor, researches using thermal fingerprints and methods utilizing differences in the morphology of materials are being studied . The gas sensing material forms a thermal fingerprint because there is a difference in response to each noxious gas at a particular temperature.…”

Sensor Arrays Based on Polycyclic Aromatic Hydrocarbons: Chemiresistors versus Quartz-Crystal Microbalance

“…12,23 The implementation of the sensors should be simple and cost-effective enough to be economically viable for real-world applications. Sensors with electronic and electro-acoustic transduction mechanisms, such as chemically sensitive resistors [24][25][26][27][28][29][30][31][32][33] and quartz-crystal microbalance (QCM) sensors [34][35][36] are among the most attractive and widespread elements for sensing applications that involve the detection and classification of volatile organic compounds (VOCs) in the gas phase. 9,11,13,16,19,20,24,37 Recently, we have shown that polycyclic aromatic hydrocarbon (PAH) derivatives as sensing materials in chemiresistors, field effect transistors or QCM sensors can provide good sensitivity and robust selectivity towards different polar and nonpolar VOCs, while being highly tolerant even to drastic humidity variations.…”