Electronic Noses: From Advanced Materials to Sensors Aided with Data Processing

Abstract

Artificial olfaction, i.e., e‐nose, plays a critical function in robotics by mimicking the human olfactory organ that can recognize different smells that correlate with a range of fields, including environment monitoring, disease diagnosis, public security affairs, agricultural production, food industry, etc. The advances in the artificial olfaction (electronic nose) technology and its applications are concisely reviewed herein. Three main elements are investigated and presented, with an emphasis on the emerging sensors and algorithm of the artificial neural network in the relevant fields. The first element is the diverse applications of e‐nose in medical care, food industry, environment monitoring, public security affairs, and agricultural production. The second element is the investigation of the sensors in e‐nose and representative and promising advances, which is the building block of e‐nose through mimicking the olfactory receptors. The third element is the introduction to the algorithm of the artificial neural network to serve in the recognition of the pattern of odors (i.e., their chemical profiles). Promises and challenges of the separately reviewed parts and the combined parts are presented and discussed. Ideas regarding further orientation and development of the e‐nose system are also considered.

Gas Sensors Based on Chemi-Resistive Hybrid Functional Nanomaterials

“…Monitoring and recording chemical stimulus or variations in the environment are increasingly important in future production and daily life of human health [1]. Achieving this goal relies on the availability of high-performance sensor units that are capable of detecting gas analytes, such as volatile/semi-volatile organic compounds (VOCs/SVOCs) highly rich regarding critical information for the detection, monitoring and closed-loop control in many fields, including medicine, food industry, environmental monitoring, public security, and agricultural production [2,3].…”

“…Table 10 summarizes the recent applications of e-nose for monitoring environment. E-nose is widely used in agricultural to analyze growth, classify seeds, detect the maturity, monitor quality, which promoted agricultural modernization and saved labor [2]. Eight MOS sensors produced by FIS (Osaka, Japan), MQ (Hanwei, China), and TGS (Figaro Engineering Inc.) were applied for classifying cumin, caraway, and other seeds [179].…”

Robust High‐Capacitance Polymer Gate Dielectrics for Stable Low‐Voltage Organic Field‐Effect Transistor Sensors

“…Two important considerations for fabrication of a low‐voltage OFET chemical sensor are i) the OSC layer has to be placed in a position that permits exposure to the analyte, that is, in a bottom‐gate device geometry, and ii) the gate dielectric material requires a large areal capacitance ( C i ) and good electrical insulation, but it needs to be chemically robust to withstand the solvents used to solution process the OSC layer in this geometry 4. A gate dielectric that meets these requirements would enable the development of low‐powered sensing platforms such as electronic noses for multi‐analyte detection where an array of OSC sensing elements is required 5…”

How Can Odors Be Measured? An Overview of Methods and Their Applications

“…Electronic noses are instruments designed to mimic mammalian olfaction in the detection and characterization of simple or complex odors. These devices allow the characterization of mixtures of organic samples as a whole, providing their olfactory fingerprint, without recognizing the individual odor-generating compounds, as the human nose does [64,65].…”