LPG sensing application of ex situ PPy-Bi2O3-MOX (MOX=ZrO2, Ag2O and TiO2) nanocomposites

PPy-Bi2O3-MOX (MOX=ZrO2, Ag2O and TiO2) nanocomposites have been synthesized by ex situ approach. PPy-Bi2O3-MOX (MOX=ZrO2, Ag2O and TiO2) nanocomposites sensors have been fabricated for LPG sensing application. The nanocomposites have been characterized by using X-ray diffraction (XRD), scanning electron microscopy (SEM), ultra violet visible spectroscopy (UV-Vis) and thermo gravimetric-differential thermal analyzer (TG-DTA) techniques. SEM micrograph exhibits irregular morphology, appropriate for gas sensing application. XRD reveals that all nanocomposites have amorphous nature. Among all the nanocomposites PBZr (PPy-Bi2O3-ZrO2) nanocomposite sensor has found good LPG sensing performance. PBZr nanocomposite sensor also exhibits better selectivity and stability against LPG. This sensor has low operating temperature against LPG of the order of 323 K and fast response and recovery time

Synthesis and Complex Optical Characterization of Polythiophene/Poly (vinyl acetate) Composite Thin Films for Optoelectronic Device Applications

430-436In the present communication, Polythiophene/poly(vinyl acetate) (PTh/PVAc) composite thin films were synthesized by chemical oxidative polymerization method in methanol is reported. The prepared composite were characterized through X-ray diffraction (XRD), Field emission scanning electron microscopy (FE-SEM), ultraviolet-visible (UV-Vis)spectroscopy and photoluminescence (PL) measurement. The broad peak was displayed in the PL spectra for the preparedcomposite at around 390 nm, proposed prodigious charge generation efficiency. The analysis of the optical parameters of theprepared composite was carried out by spectral analysis using a UV-Vis spectrophotometer. The obtained results, whichwere as follows: energy band gap of 4.58–5.31 eV, complex refractive index coefficient values of 1.175–1.193 and opticalconductivity values in the range of 2.58×108–5.24×108 S.cm-1 at 270 nm. The above results shows the studied compositefilms are expected to offer potential applications in optoelectronic devices

Investigation of optical properties of sodium superoxide loaded polyaniline in uv and visible region

The PANi/NaO2 composites were prepared using an ex-situ technique in 5–20 wt.% range. The NaO2 was prepared in a single step by heating sodium nitrate in oxygen rich environment. Ultraviolet-visible spectroscopy was employed to extract optical parameters like direct band gap, refractive index, complex dielectric constant and optical conductivity. The refractive index increased with NaO2 content for 5 and 10 wt. %, and then decreased possibly due to non-bridging oxygen (NBO) atoms. The composite with 10 wt. % NaO2 showed the largest refractive index. On increasing the concentration of NaO2, the band gap decreased from 2.538 to 2.307 eV and became narrower. Beyond 225 nm wavelength the extinction coefficient increased linearly, indicating that light trapping was proportional to wavelength. Both parts of the dielectrics follow the same pattern and the real dielectric constant is higher than the imaginary dielectric constant. The optical conductivity increased with h due to a change in density of localized states in the band gap, and also possibly due to the electrons excited by photon energy

Characterizing the electro-optical properties of polyaniline/poly(vinyl acetate) composite films as-synthesized through chemical route

In this study, the conductive polymer polyaniline/poly(vinyl acetate) PANi/PVAc composite thin films were synthesized by chemical oxidative polymerization method with ammonium per sulfate​ as an oxidizing agent in methanol. The as-synthesized composite were characterized by X-ray diffraction (XRD), Scanning electron microscopy (SEM), ultraviolet–visible (UV–Vis) spectroscopy and photoluminescence (PL) measurement. The temperature dependence of DC electrical conductivity measurements were carried out through a two probe technique. The broad peak was found in the PL spectra of the obtained composite at around 450 nm, suggested that the obtained composite retains more charge generation efficiency. The enhancement in the optical and electrical properties of PANi/PVAc composite makes it as a novel candidate in various optoelectronic applications

Synthesis, characterization and CO₂ gas sensing response of SnO₂/Al₂O₃ double layer sensor

816-819Tin dioxide (SnO2) material changes its properties depending on the ambient gas which can be utilized as gas sensing materials. Usually changes in electrical resistance/conductance in response to environmental gases are monitored. SnO2 and double layer (SnO2/Al2O3) sensors have been prepared by screen-printing technique on glass substrate. The sensors were used for different concentration (ppm) of CO2 gas investigation at different temperature. The sensing response (sensitivity) of SnO2/Al2O3 double layer sensor was found to be higher, compared with pure SnO2 sensor. The average grain size of SnO2 was determined from XRD pattern and found to be 120.7 nm. The activation energy (Ea) of first order reaction (n =1) for SnO2 has been found to be 72.06 kJ/g-mol from endo DDTA and 325.95 kJ/g-mol from exo DDTA. The microstructure of SnO2 has been studied from SEM analysis. The oxygen ions adsorb onto the surface of material removes electrons from the bulk and create a potential barrier that limits electron movement and resistivity. When exposed to an oxidizing gas such as CO2 then it is chemisorbed on bridging oxygen atoms with the formation of a surface carbonate, subsequently increasing the barrier height and resistivity

Molecular interactions in CdCl2/H2C2O4 nanofluid using acoustical studies at room temperature

Nanofluids have been prepared by dispersing nanometer size particles in base fluid. The very essence of nanofluids research and development has to enhance the fluid macroscopic and mega scale properties such as thermal conductivity through manipulating microscopic physics. The acoustical properties of rhombohedral symmetry CdCl2/H2C2O4 nanofluids have been studied using ultrasonic technique at room temperature (303 K). The ultrasonic velocity, density and viscosity of nanofluids have been measured to manipulate the acoustical parameters such as specific acoustic impedance, adiabatic compressibility, internal pressure, viscous relaxation time, relative association, Gibbs free energy, intermolecular free length to know the molecular interaction. The particle size of CdCl2/H2C2O4 fluid was estimated by using UV-Vis analysis. The results were discussed and compared with experimental and theoretical facts

Ultra-violet C absorption and LPG sensing study of zinc sulphide nanoparticles deposited by a flame-assisted spray pyrolysis method

AbstractSolvent processed spray pyrolysis is a technique that has attracted worldwide interest for the synthesis of nanoparticles. Zinc sulphide (ZnS) belongs to a category of practical semiconductors known as metal sulphides, and it is used extensively as an optical material. In the present article, ZnS nanoparticles were successfully synthesized using flame-assisted spray pyrolysis. X-ray diffraction confirmed the formation of ZnS with an excellent crystalline structure, while scanning electron microscopy indicated that the as-synthesized materials were nanoparticles. Ultraviolet–visible spectroscopy was utilized to evaluate the optical property of the resulting product and revealed that ZnS nanoparticles have the capacity to absorb ultra-violet C. In addition, various liquefied petroleum gas (LPG) sensing properties of the ZnS nanoparticles were also evaluated

LPG sensing performance of CuO–Ag2O bimetallic oxide nanoparticles

In the present article, we synthesized CuO–Ag2O bimetallic oxide nanoparticles by using microwave assisted and solid state diffusion routes. The structural, morphological, optical and thermal study of as-synthesized materials were done through X-ray diffractometer (XRD), scanning electron microscope (SEM), Fourier transform infrared (FTIR), ultraviolet–visible (UV–vis) and thermogravimetric analysis (TGA), respectively. Comparatively different sensing parameters such as sensing response at room temperature, operating temperature, response and recovery time and stability characteristics were investigated and discussed for liquefied petroleum gas (LPG). The CuO–Ag2O bimetallic oxide nanoparticles synthesized by microwave assisted route shows good gas sensing properties

Exploring the electrical and complex optical properties of as-synthesized thiophene-indole conducting copolymers

In this contest, a novel series of random thiophene-indole (Th-In) conducting copolymers have been synthesized through oxidative copolymerization of their monomers in aqueous medium at room temperature using anhydrous ferric chloride (FeCl3) as an oxidant. The structure of as-studied samples have been confirmed through X-ray diffraction (XRD) technique. Field emission-scanning electron microscopy (FE-SEM) ensured the morphology of as-prepared copolymers. The complex optical parameters of the samples have been estimated through ultraviolet-visible (UV-Vis) spectroscopy. The temperature dependence of dc electrical conductivity of the samples have been obtained over a temperature range 303–393 K, which found to be in the range 10−6–10−4 Scm−1 followed Arrhenius relation. The degradation behaviour has been studied through thermogravimetry (TG) and differential thermal analysis (DTA) techniques