Gas Identification by a Single Metal-Oxide-Semiconductor Sensor Assisted by Ultrasound

Abstract

The gas identification technology has huge potential applications in medical diagnoses, food industries, early warning of poisonous gas leakage, fire prevention, antiterrorism, military, etc. Although electronic noses may be used to identify different gases, it has been a big challenge to identify gases by a single sensor. In this work, we demonstrate a novel gas identification strategy based on a single metaloxide-semiconductor (MOS) sensor assisted by an ultrasound. The identification is based on different ultrasonic effects on the steady sensing responses of an ultrasonically radiated MOS gas sensor to different target gases. It does not need a complicated feature extraction computation. Our experiments show that the success rate of identification can be up to 100% if strong enough ultrasound is employed. The identification process can also give the concentration of the gas to be identified. The identification result is immune to the interference of impurity gases to some extent. The anti-interference capability may be strengthened by increasing the vibration velocity and choosing proper sensing materials.

Advances in ultrasound-responsive hydrogels for biomedical applications

“…[63][64][65][66] Compared with other stimulation conditions, ultrasonic triggering is noninvasive, safe, controllable, and economical, and thus deserves attention under novel triggering conditions. Currently, ultrasoundresponsive hydrogels, combining the characteristics of hydrogels and ultrasound, have made many outstanding achievements in biomedical applications, such as drug delivery, [67][68][69][70][71] biomedical imaging 64,72,73 and smart materials, [74][75][76][77] and shown increasingly powerful functions in biomedical applications.…”

Gas Identification by Simultaneous Permeation through Parallel Membranes: Proof of Concept

“…Qualitative analysis (chemical identification) of a sample or sample components can be an objective in its own and may not necessitate subsequent quantitative measurements. The opposite scenario is not always true since quantitative analysis requires prior identification of the analytes to be quantified. − It is hard to overestimate the importance of chemical identification which is considered as a growing area of research to provide responses to yes/no questions. ,, …”

“…These include infra-red spectroscopy, , mass spectrometry, , Raman spectroscopy, photoacoustic spectroscopy, and using electronic nose systems based on different types of sensor arrays. − Nowadays, electronic nose systems are employed as the primary gas identification means, which typically involve sensor arrays, signal acquisition and processing, pattern recognition, and reference database. The common sensor types utilized in electronic noses are metal oxide semiconductors , and chemiresistive, electrochemical, gravimetric (SAW, BAW, QCM, etc. ), colorimetric, and fluorometric sensors .…”

Aqueous Microlenses for Localized Collection and Enhanced Raman Spectroscopy of Gaseous Molecules

“…Electronic sensors based on nanomaterials [39][40][41] are highly sensitive to VOCs including CWAs, but identifying such gaseous analytes has been challenging, even after surface treatment with receptors. [36,42,43] Therefore, developing a technology that enables the Raman spectroscopy of gaseous molecular species is critical for identifying chemicals in the environment.Raman spectroscopy of gaseous molecules has been challenging, requiring complicated experimental procedures and peripheral devices for concentrating the analytes. Here, Raman spectroscopy of gaseous molecules at parts-per-billion (ppb) levels is demonstrated using aqueous microlenses of LiCl solution that spontaneously absorb water-soluble gas molecules from the environment.…”

“…Electronic sensors based on nanomaterials [39][40][41] are highly sensitive to VOCs including CWAs, but identifying such gaseous analytes has been challenging, even after surface treatment with receptors. [36,42,43] Therefore, developing a technology that enables the Raman spectroscopy of gaseous molecular species is critical for identifying chemicals in the environment.…”