Nanocrystalline copper bromide (γ-CuBr) has been synthesized by hydrothermal method. The as-synthesized sample was characterized for its structural and microstructural properties using powder X-ray diffraction, electron diffraction and high resolution transmission electron microscope. The surface characteristics and optical properties of the sample were further studied with spectroscopy techniques such as FT-IR transmittance, diffused reflectance and fluorescence. Further, γ-CuBr nanocrystals was used as a gas sensing material in clad-modified optical fiber gas sensing system to explore its sensing behaviour for acetone (C3H6O), ammonia (NH3) and ethanol (C2H5OH). As compared with other gases, γ-CuBr nanocrystals showed superior sensitivity and specificity to acetone gas. The mechanism involved in the present, clad-modified optical fiber acetone sensor was discussed in detail. © 2018

Balusamy Renganathan

Acetone

Ammonia

Bromine compounds

Catalyst selectivity

Chemical detection

GAS DETECTORS

Nanocrystals

Optical fibers

Optical properties

ACETONE SENSOR

Evanescent wave

Hydrothermal methods

Micro-structural properties

Nanocrystalline copper

Powder X ray diffraction

Sensitivity and Specificity

Surface characteristics

Copper compounds

IIT Madras is a public technical and research university located in Chennai, Tamil Nadu. Founded in 1959, it is recognised as an Institute of National Importance.

IIT Madras has been ranked as the top engineering institute in India for four years in a row by the National Institutional Ranking Framework of the MHRD

It currently offers undergraduate, postgraduate and research degrees across 16 disciplines in Engineering, Sciences, Humanities and Management. About 596 faculty belonging to science and engineering departments and centres of the Institute are engaged in teaching, research and industrial consultancy.

IIT Madras

Materials Science in Semiconductor Processing

The promising radiation technology was inculcated for the enhancement of gas sensing performance of fibre optic gas sensor. Magnesium tetraborate (MTB), known for its radiation dosimetry and frequency conversion application was used as a sensor element. Solid state sintering technique was adopted for the preparation of polycrystalline samples. In order to understand the role of crystallinity in gas sensing property, the glasses of magnesium tetraborate was synthesize by following melting-quenching method. Cerium (Ce) was doped with MTB in 0.25 mol% concentration. XRD pattern reveals the perfect incorporation of dopant without changing the crystal structure of the host and the cell parameters are matches well with standard ICDD data (031-0787). UV–Vis absorption spectra show the lack of any strong absorption in visible region. Irrespective of crystalline nature, the gas sensitivity of pristine MTB is highly negligible say, 2 counts/50 ppm and 1 counts/50 ppm respectively. Interestingly, gamma radiation treated MTB:Ce samples shows excellent sensitivity of 35 counts/50 ppm and 46 counts/50 ppm towards acetone vapours. Based on the obtained results, gamma irradiated cerium doped MTB glass is suggested as a best sensor for the detection of acetone with high sensitivity. © 2019 Elsevier Inc.

Optical Fiber Technology

Gamma radiation impact on the fiber optic acetone gas sensing behaviour of magnesium tetraborate

A clad modified optical fiber gas sensor for sensing volatile organic compound vapours (VOCs) such as formaldehyde (HCHO), ammonia (NH3), ethanol (C2H5OH) and methanol (CH3OH) up to 500 ppm was studied using nanocrystalline nickel oxide embedded coatings. Prior to the measurements, nickel oxide in two different crystallite sizes such as 24 nm and 76 nm was synthesized by calcination of reverse precipitated nickel hydroxide subsequently at 450 °C and 900 °C for 30 min. Then, samples physical properties were characterized using X-ray diffraction (XRD), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM) and high resolution transmission electron microscopy (HRTEM). Our gas sensing measurement concludes that the lower crystallite size (24 nm) nickel oxide nanocrystals exhibits superior performance to formaldehyde and ethanol vapours as compared with other two VOCs, the observed experimental results were discussed in detail. © 2017 Elsevier Inc.

Clad modified optical fiber gas sensors based on nanocrystalline nickel oxide embedded coatings

A fiber optic gas sensor with a PMMA fiber whose clad is modified with chemically sensitive nano-crystalline zinc oxide has been developed and investigated to detect acetone, isopropyl alcohol and benzene gases. The spectral characteristics of the sensor were recorded for different concentrations ranging from (0-500 ppm) for these gases both with as-prepared and annealed nanocrystalline ZnO, and the influence of annealing on the gas sensing has been studied.The response time and recovery time were found to be 48 min. and 42 min. respectively for 500 ppm concentration. © 2013 Elsevier Inc. All rights reserved.

Fiber optic gas sensor with nanocrystalline ZnO

A clad-modified fiber optic sensor with nanocrystalline CeO2 is proposed for gas detection. As-prepared and annealed CeO2 (500 C) samples have been used as gas sensing media. The spectral characteristics of the fiber optic gas sensor are studied for various concentrations of ammonia, ethanol and methanol gases (0-500 ppm). The sensor exhibits linear variation in the spectral peak intensity with the gas concentration. The characteristics of the sensor are also studied for gas selectivity. The time response characteristics of the sensor are reported. © 2013 Elsevier B.V. All rights reserved.

Current Applied Physics

Nanocrystalline cerium oxide coated fiber optic gas sensor

Fiber optic gas sensors with nanoparticles of V2O5 and WO3 as the cladding of a PMMA fiber have been proposed in this work. The spectral response of these sensors for detection of ammonia, methanol and ethanol under various concentrations has been studied at room temperature. The time response characteristics of the sensors are also presented. © 2013 Elsevier B.V. All rights reserved.

Optics Communications

Fiber optic gas sensors with vanadium oxide and tungsten oxide nanoparticle coated claddings

Nanocrystalline Sm2O3 coated fiber optic sensor is proposed for detecting toxic gases such as ammonia, methanol and ethanol vapors. Sm2O3 in the as prepared form as well as annealed form have been used as gas sensing materials, by making them as cladding of a PMMA fiber. The spectral characteristics of the Sm2O3 gas sensor are presented for ammonia, methanol and ethanol gases with different concentrations ranging from 0 to 500 ppm. The sensor exhibits a linear variation in the output light intensity with the concentration. The enhanced gas sensitivity and selectivity of the sensor for ethanol is discussed briefly. © 2014 Elsevier B.V.

Materials Science and Engineering B: Solid-State Materials for Advanced Technology

Nanocrystalline samarium oxide coated fiber optic gas sensor

Acetone sensing behaviour of optical fiber clad-modified with γ-CuBr nanocrystals

Journal	Data powered by TypesetMaterials Science in Semiconductor Processing
Publisher	Data powered by TypesetElsevier Ltd
ISSN	13698001
Open Access	No