Chemical sensors for specific species with varying sensitivity levels are commercially available.... more Chemical sensors for specific species with varying sensitivity levels are commercially available. Common chemical sensors defer in terms of the sensing material and the nature of property change such as electrical conductivity, optical characteristics and temperature. Some of the current sensor technologies include high temperature oxide thin-film sensors, polymer based sensors, catalytic based sensors and surface acoustic wave (SAW) sensors are described. In this the sensor array consists of Carbon Nano Tube (CNT) as sensing material and an interdigitated electrode as a transducer is described. The gas sensors fabricated by using conducting polymers such as polyaniline, polypyrrole as the active layers have been reviewed. The macroscopic coaxial carbon cylinders consisting of aligned CNT stacks have been used in CNTpolymer composite. The advantages and disadvantages of each sensor technology are also highlighted. All these technologies have been used for the development of highly s...
Abstract Undoped and tin (Sn) doped cadmium sulfide (CdS) semiconductor alloy nanoparticles have ... more Abstract Undoped and tin (Sn) doped cadmium sulfide (CdS) semiconductor alloy nanoparticles have been prepared by simple solvothermal microwave irradiation (SMI) technique. Powder X-ray diffraction (PXRD) analysis indicates the formation of hexagonal structured high-quality nanoparticles with crystallite size around 3 nm. The particle size of the samples obtained from transmission electron microscopy (TEM) analysis is in accordance with the crystallite size of prepared nanoparticles. The surface morphology examined using a field emission scanning electron microscope shows the uniform distribution of spherical nanoparticles. The energy dispersive X-ray (EDX) analysis confirms the purity of the prepared nanoparticles with a good stoichiometric ratio of Cd, S, and Sn. The optical characteristic of the samples by UV–Visible (UV–Vis.) analysis implies that the optical band gap tends to decrease for the increase in Sn concentration in CdS lattices. Dye-sensitized solar cell with 4 mol % Sn doped CdS nanoparticles shows ~39% higher efficiency than that of undoped CdS.
The characterization of a custom-designed GC-based SAW e-Nose sensor system is presented here to ... more The characterization of a custom-designed GC-based SAW e-Nose sensor system is presented here to study the sensing ability of the sensor system to detect and identify low medium and high toxic vapors. A semi-automated multi-vapor generator generates vapors of chemical compounds that are then exposed to the sensing system to examine its performance under various concentrations. Time-domain verses frequency response of GC-SAW Sensor is noted for repeated cycles against different chemical compounds like xylene, 1,2 dibromoethane, dimethyl sulfate, triethyl phosphate, nitrobenzene, phosphorous trichloride being tested. The generated data is examined using a principle component analysis (PCA) technique to detect a unique response for an individual chemical compound. Experimental results are reported.
Detection and identification of toxic environmental gases have assumed paramount importance preci... more Detection and identification of toxic environmental gases have assumed paramount importance precisely in the defense, industrial and civilian security sector. Numerous methods have been developed for the sensing of toxic gases in the environment ever since surface acoustic wave (SAW) technology came into existence. Such SAW sensors called electronic nose (E-Nose) sensor use the frequency response of a delay line/resonator. SAW device is focused and given importance. The selective coating between input and output interdigital transducers (IDTs) in the SAW device is responsible for corresponding changes in operating frequency of the device for a specific gas/vapour absorbed from the environment. A suitable combination of well-designed SAW delay lines with selective coatings not only help to improve sensor sensitivity and selectivity but also leads to the minimization of false frequency alarms in the E-Nose sensor. This article presents a comprehensive review of design, development, si...
Surface Acoustic Wave (SAW) devices like delay lines, filters, resonators etc., are nowadays exte... more Surface Acoustic Wave (SAW) devices like delay lines, filters, resonators etc., are nowadays extensively used as principal solid state components in many electronic applications and chemical vapour sensors. To bring out the best from these SAW devices, computational design and modelling are resorted too. The present paper proposes the modelling of 400 MHz ST-X Quartz based SAW delay line, by three models namely, Impulse Response Model (IRM), Crossed-field Equivalent Circuit Model (ECM) and Couplingof-Modes (COM) model. MATLAB is employed as a computational tool to model the experimental output of the SAW device. A comparative discussion of the modelled device results is also provided.
Chemical sensors for specific species with varying sensitivity levels are commercially available.... more Chemical sensors for specific species with varying sensitivity levels are commercially available. Common chemical sensors defer in terms of the sensing material and the nature of property change such as electrical conductivity, optical characteristics and temperature. Some of the current sensor technologies include high temperature oxide thin-film sensors, polymer based sensors, catalytic based sensors and surface acoustic wave (SAW) sensors are described. In this the sensor array consists of Carbon Nano Tube (CNT) as sensing material and an interdigitated electrode as a transducer is described. The gas sensors fabricated by using conducting polymers such as polyaniline, polypyrrole as the active layers have been reviewed. The macroscopic coaxial carbon cylinders consisting of aligned CNT stacks have been used in CNTpolymer composite. The advantages and disadvantages of each sensor technology are also highlighted. All these technologies have been used for the development of highly s...
Abstract Undoped and tin (Sn) doped cadmium sulfide (CdS) semiconductor alloy nanoparticles have ... more Abstract Undoped and tin (Sn) doped cadmium sulfide (CdS) semiconductor alloy nanoparticles have been prepared by simple solvothermal microwave irradiation (SMI) technique. Powder X-ray diffraction (PXRD) analysis indicates the formation of hexagonal structured high-quality nanoparticles with crystallite size around 3 nm. The particle size of the samples obtained from transmission electron microscopy (TEM) analysis is in accordance with the crystallite size of prepared nanoparticles. The surface morphology examined using a field emission scanning electron microscope shows the uniform distribution of spherical nanoparticles. The energy dispersive X-ray (EDX) analysis confirms the purity of the prepared nanoparticles with a good stoichiometric ratio of Cd, S, and Sn. The optical characteristic of the samples by UV–Visible (UV–Vis.) analysis implies that the optical band gap tends to decrease for the increase in Sn concentration in CdS lattices. Dye-sensitized solar cell with 4 mol % Sn doped CdS nanoparticles shows ~39% higher efficiency than that of undoped CdS.
The characterization of a custom-designed GC-based SAW e-Nose sensor system is presented here to ... more The characterization of a custom-designed GC-based SAW e-Nose sensor system is presented here to study the sensing ability of the sensor system to detect and identify low medium and high toxic vapors. A semi-automated multi-vapor generator generates vapors of chemical compounds that are then exposed to the sensing system to examine its performance under various concentrations. Time-domain verses frequency response of GC-SAW Sensor is noted for repeated cycles against different chemical compounds like xylene, 1,2 dibromoethane, dimethyl sulfate, triethyl phosphate, nitrobenzene, phosphorous trichloride being tested. The generated data is examined using a principle component analysis (PCA) technique to detect a unique response for an individual chemical compound. Experimental results are reported.
Detection and identification of toxic environmental gases have assumed paramount importance preci... more Detection and identification of toxic environmental gases have assumed paramount importance precisely in the defense, industrial and civilian security sector. Numerous methods have been developed for the sensing of toxic gases in the environment ever since surface acoustic wave (SAW) technology came into existence. Such SAW sensors called electronic nose (E-Nose) sensor use the frequency response of a delay line/resonator. SAW device is focused and given importance. The selective coating between input and output interdigital transducers (IDTs) in the SAW device is responsible for corresponding changes in operating frequency of the device for a specific gas/vapour absorbed from the environment. A suitable combination of well-designed SAW delay lines with selective coatings not only help to improve sensor sensitivity and selectivity but also leads to the minimization of false frequency alarms in the E-Nose sensor. This article presents a comprehensive review of design, development, si...
Surface Acoustic Wave (SAW) devices like delay lines, filters, resonators etc., are nowadays exte... more Surface Acoustic Wave (SAW) devices like delay lines, filters, resonators etc., are nowadays extensively used as principal solid state components in many electronic applications and chemical vapour sensors. To bring out the best from these SAW devices, computational design and modelling are resorted too. The present paper proposes the modelling of 400 MHz ST-X Quartz based SAW delay line, by three models namely, Impulse Response Model (IRM), Crossed-field Equivalent Circuit Model (ECM) and Couplingof-Modes (COM) model. MATLAB is employed as a computational tool to model the experimental output of the SAW device. A comparative discussion of the modelled device results is also provided.
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