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.

Angarai Ramanathan Ganesan

Department Of Physics

Balusamy Renganathan

Catalyst selectivity

Chemical sensors

Crystallite size

Ethanol

Field emission microscopes

Formaldehyde

Fourier transform infrared spectroscopy

GAS DETECTORS

Gas sensing electrodes

High resolution transmission electron microscopy

Nanocrystals

Nickel coatings

Optical fibers

Scanning electron microscopy

Thermogravimetric analysis

Volatile organic compounds

X ray diffraction

CRYSTALLITE SIZE EFFECTS

ETHANOL VAPOURS

Field emission scanning electron microscopy

gas sensing

NANO-CRYSTALLINE NICKEL

NICKEL HYDROXIDES

OPTICAL FIBER GAS SENSORS

OXIDE NANOCRYSTALS

Nickel oxide

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

Optical Fiber Technology

Clad-modified fibre optic ammonia sensor was developed subsequently using pure V2O5, MoO3, and its composites with TiO2. Prior to the sensing measurement, the composite was synthesised and studied for the structural and microstructural properties using powder X-ray diffractometer and field emission scanning electron microscope. The analysis confirms the existence of nanocrystalline anatase phase TiO2 in the grain boundaries of microcrystalline V2O5/MoO3 in the composites. Ammonia sensing measurement was performed for different concentrations of ammonia exposures up to 500 ppm. The obtained response was applied to calculate the sensitivity and it was found to be superior for the clad modified with composite material as compared to the pure microcrystalline samples are discussed in detail. © 2019The Institution of Engineering and Technology.

Micro and Nano Letters

Evanescent wave ammonia sensor: Influence of nanocrystalline tio2 on v2o5 and moo3

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.

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

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

Materials Science in Semiconductor Processing

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

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

Optics & Laser Technology

Transition metal doped nanocrystalline Li2B4O7 for gas sensing applications

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

Journal	Optical Fiber Technology
Publisher	Academic Press Inc.
ISSN	10685200
Open Access	No