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Journal ArticleDOI

Interfacial Engineering in TiO 2 /Nano-Si Heterostructure-Based Device Prototype for E-Nose Application

21 Feb 2018-IEEE Transactions on Electron Devices (Institute of Electrical and Electronics Engineers (IEEE))-Vol. 65, Iss: 3, pp 1127-1131
TL;DR: In this article, the selective and highly sensitive performance of porous TiO2/nano-Si heterostructure for ethanol sensing was presented, where the sensor response was recorded as a change in resistance upon exposure to a variety of organic vapors in the concentration range of 5-500 ppm and in simulated real breath conditions.
Abstract: This paper presents the selective and highly sensitive performance of porous TiO2/nano-Si heterostructure for ethanol sensing. The fabrication steps involved were scalable and reproducible making the device eligible for batch fabrication suitable for industry production. The sensor response was recorded as a change in resistance upon exposure to a variety of organic vapors in the concentration range of 5–500 ppm and in simulated real breath conditions. Although the response was obtained at room temperature, however, the operating temperature of the sensor was found to be around 100 °C. The sensing mechanism has been explained on the basis of adsorption–desorption theory of gases, physical, and chemical properties of the materials. A prototype was built for complete realization of the sensor. The sensor data from the sensor array comprising of hetersostructure and its single-layer counterparts were collated and signal conditioning like Regression model and PCA was done. These were used for assessing the alcohol concentration and separation of analytes for the development of E-nose system.
Citations
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Journal ArticleDOI
TL;DR: The C-dot-IDE platform is robust, reusable, readily assembled from inexpensive building blocks and constitutes a versatile and powerful vehicle for gas sensing in general, bacterial monitoring in particular.
Abstract: Continuous, real-time monitoring and identification of bacteria through detection of microbially emitted volatile molecules are highly sought albeit elusive goals. We introduce an artificial nose for sensing and distinguishing vapor molecules, based upon recording the capacitance of interdigitated electrodes (IDEs) coated with carbon dots (C-dots) exhibiting different polarities. Exposure of the C-dot-IDEs to volatile molecules induced rapid capacitance changes that were intimately dependent upon the polarities of both gas molecules and the electrode-deposited C-dots. We deciphered the mechanism of capacitance transformations, specifically substitution of electrode-adsorbed water by gas molecules, with concomitant changes in capacitance related to both the polarity and dielectric constants of the vapor molecules tested. The C-dot-IDE gas sensor exhibited excellent selectivity, aided by application of machine learning algorithms. The capacitive C-dot-IDE sensor was employed to continuously monitor microbial proliferation, discriminating among bacteria through detection of distinctive “volatile compound fingerprint” for each bacterial species. The C-dot-IDE platform is robust, reusable, readily assembled from inexpensive building blocks and constitutes a versatile and powerful vehicle for gas sensing in general, bacterial monitoring in particular.

15 citations

Book ChapterDOI
01 Jan 2023

1 citations

References
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Book
20 Dec 1999
TL;DR: Fundamentals of discrete-time signal processing random variables, vectors, and sequences linear signal models, and structure for optimum linear filters least-squares filtering and prediction signal modelling and parametric spectral estimation adaptive filters array processing are studied.
Abstract: Fundamentals of discrete-time signal processing random variables, vectors, and sequences linear signal models nonparametric power spectrum estimation optimum linear filters algorithms and structure for optimum linear filters least-squares filtering and prediction signal modelling and parametric spectral estimation adaptive filters array processing further topics. Appendices: useful results from matrix algebra and optimization theory MATLAB functions.

573 citations


"Interfacial Engineering in TiO 2 /N..." refers methods in this paper

  • ...These coefficients are obtained using least-squares approximation [24]....

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Journal ArticleDOI
TL;DR: In this paper, the frequency and linewidth of the four Raman active modes in anatase have been investigated over the temperature range 20 to 1100 K. The results indicate that the anomalous T dependence of the 399 cm -1 mode reflects the near cancellation of the cubic and quartic contributions to the frequency shift.
Abstract: The frequency and linewidth of the four Raman active modes in anatase have been investigated over the temperature range 20 to 1100 K. The temperature ( T ) dependence of the frequency of the 639 cm -1 mode showed typical behavior in normal ionic crystals, whereas the other modes at 399, 197 and 144 cm -1 did anomalous behavior. These T dependent results were combined with pressure dependent results, thermal expansion and compressibility data to evaluate the pure-volume and pure-temperature contributions to the T dependence of each frequency. The results indicate that the anomalous T dependence of the 399 cm -1 mode reflects the near cancellation of the cubic and quartic contributions to the frequency shift, and that of the modes at 197 and 144 cm -1 arises from strong quartic contributions. The T dependence of the linewidth is well explained qualitatively in terms of simple anharmonic effects involving three phonon processes.

355 citations


"Interfacial Engineering in TiO 2 /N..." refers background in this paper

  • ...2(d) display Raman-active lattice vibrations assigned to B1g and pertains to Ti–Ti covalent interactions at 144 cm−1 [19]....

    [...]

Journal ArticleDOI
19 Jan 2011-Sensors
TL;DR: This paper summarizes the major electronic-nose technologies developed for healthcare and biomedical applications since the late 1980s when electronic aroma detection technologies were first recognized to be potentially useful in providing effective solutions to problems in the healthcare industry.
Abstract: The research and development of new electronic-nose applications in the biomedical field has accelerated at a phenomenal rate over the past 25 years. Many innovative e-nose technologies have provided solutions and applications to a wide variety of complex biomedical and healthcare problems. The purposes of this review are to present a comprehensive analysis of past and recent biomedical research findings and developments of electronic-nose sensor technologies, and to identify current and future potential e-nose applications that will continue to advance the effectiveness and efficiency of biomedical treatments and healthcare services for many years. An abundance of electronic-nose applications has been developed for a variety of healthcare sectors including diagnostics, immunology, pathology, patient recovery, pharmacology, physical therapy, physiology, preventative medicine, remote healthcare, and wound and graft healing. Specific biomedical e-nose applications range from uses in biochemical testing, blood-compatibility evaluations, disease diagnoses, and drug delivery to monitoring of metabolic levels, organ dysfunctions, and patient conditions through telemedicine. This paper summarizes the major electronic-nose technologies developed for healthcare and biomedical applications since the late 1980s when electronic aroma detection technologies were first recognized to be potentially useful in providing effective solutions to problems in the healthcare industry.

325 citations

Journal ArticleDOI
Jing Guo1, Jun Zhang1, Min Zhu1, Dianxing Ju1, Hongyan Xu1, Bingqiang Cao1 
TL;DR: In this paper, a high performance gas sensor based on Au-functionalized ZnO nanorods was fabricated, where Au nanoparticles were successfully immobilized onto the surface of ZnOs to serve as a sensitizer by a facile solution reduction process.
Abstract: One-dimensional (1D) semiconductor nanostructure has been widely used for gas sensor devices. In this work, a high performance gas sensor based on Au-functionalized ZnO nanorods was fabricated. Au nanoparticles were successfully immobilized onto the surface of ZnO nanorods to serve as a sensitizer by a facile solution reduction process. The hybrid Au/ZnO nanorods have been systematically characterized by XRD, SEM, EDS, TEM and optical absorption spectrum. Gas sensing tests reveal that the Au/ZnO sensor has remarkably enhanced performance compared to pure ZnO. It could detect ethanol gas in a wide concentration range with very high response, fast response–recovery time, good selectivity and stable repeatability. The possible sensing mechanism is discussed. The superior sensing features indicate the present Au/ZnO nanorods are promising for gas sensors.

268 citations

Journal ArticleDOI
TL;DR: The differential pulse voltammetric studies revealed good sensitivity and selectivity nature of the rGO/TiO2 nanocomposite modified GCE for the detection of DA in the presence of AA.
Abstract: Titanium dioxide (TiO2) with highly exposed {001} facets was synthesized through a facile solvo-thermal method and its surface was decorated by using reduced graphene oxide (rGO) sheets. The morphology and chemical composition of the prepared rGO/TiO2 {001} nanocomposite were examined by using suitable characterization techniques. The rGO/TiO2 {001} nanocomposite was used to modify glassy carbon electrode (GCE), which showed higher electrocatalytic activity towards the oxidation of dopamine (DA) and ascorbic acid (AA), when compared to unmodified GCE. The differential pulse voltammetric studies revealed good sensitivity and selectivity nature of the rGO/TiO2 {001} nanocomposite modified GCE for the detection of DA in the presence of AA. The modified GCE exhibited a low electrochemical detection limit of 6 μM over the linear range of 2–60 μM. Overall, this work provides a simple platform for the development of GCE modified with rGO/TiO2 {001} nanocomposite with highly exposed {001} facets for potential electrochemical sensing applications.

248 citations