Time filter

Source Type

Shendage S.S.,Shivaji University | Patil V.L.,Commerce and Education College | Vanalakar S.A.,Commerce and Education College | Patil S.P.,Shivaji University | And 4 more authors.
Sensors and Actuators, B: Chemical | Year: 2017

Gas sensors based on a chemiresistive metal oxide semiconductor are widely used including nitrogen dioxide (NO2) at a moderate temperature. In this work efforts are taken to fabricate NO2 gas sensor using thin films of tungsten oxide (WO3) grown directly on to a soda-lime glass substrate without assistance of any seed layer by a simple and a facile hydrothermal technique. As per our knowledge, the deposition of nanostructured WO3 thin films without assistance of any seed layer on the glass substrate was rarely reported. The WO3 thin film samples were synthesized at various deposition times ranging from 3 h to 7 h and were characterized by X-ray diffraction, Raman spectroscopy, field emission scanning electron microscopy, transmission electron microscopy, UV–vis spectroscopy and Brunauer-Emmett-Teller techniques. The surface morphological and structural characterization showed the two dimensional (2D) nanoplate-like structure of as synthesized WO3 thin films with plate thickness ranging from 90 to 150 nm and had an orthorhombic structure, respectively. Moreover, the 2D nanoplates of WO3 exhibited a gas response ∼10 for 5 ppm for toxic NO2 gas at relatively low operating temperature. The new synthesis route and sensing behavior of as synthesized WO3 nanoplates revealed a promising candidate for the fabrication of the cost effective gas sensors. © 2016

Vanalakar S.A.,Chonnam National University | Vanalakar S.A.,Commerce and Education College | Agawane G.L.,Chonnam National University | Kamble A.S.,Chonnam National University | And 3 more authors.
Solar Energy Materials and Solar Cells | Year: 2015

Ternary chalcogenide semiconductor Cu2SnS3 (CTS) is an emerging material, attracting increasing interest for the applications in thin film solar cells. Here we report a pulsed laser deposition route to synthesize compact and single phase CTS thin films for the first time. The effects of the annealing temperature on the formation of CTS films were investigated. XRD and Raman studies revealed that the annealed CTS thin films have a polycrystalline nature with a cubic crystal structure, and the crystalline size of the CTS thin films increases as the annealing temperature increases. The direct optical band gap energy of the CTS thin film annealed at 400°C is found to be 1.01 eV. Hall effect measurements indicate that the film has a p-type conductivity with a hole mobility of 0.51 cm2/V s. Finally, a thin film solar cell was fabricated with a SLG/Mo/CTS/CdS/i-ZnO/AZO/Al structure. A photo-electric conversion efficiency of 0.82% was achieved with a short circuit current density of 11.90 mA/cm2. We are successful in achieving the better values of VOC for the CTS solar cells. The route developed here may provide an alternative approach to produce CTS thin film solar cells. © 2015 Elsevier B.V. All rights reserved.

Vanalakar S.A.,Chonnam National University | Vanalakar S.A.,Commerce and Education College | Kamble A.S.,Chonnam National University | Shin S.W.,Chonnam National University | And 6 more authors.
Solar Energy | Year: 2015

Solution-synthesized nanostructured Cu2ZnSnS4 (CZTS) has attracted significant attention as a promising candidate for use as an efficient and inexpensive photovoltaic energy convertor material. In general, the solution synthesized route involves the use of toxic and explosive chemicals. The current report emphasizes a non-toxic surfactant mediated hydrothermal route for the synthesis of CZTS NPs (CZTS NPs) without the use of toxic chemicals. The physical and chemical properties of the CZTS NPs were studied using X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM) techniques. The XRD and Raman spectroscopy results confirmed the formation of single-phase kesterite CZTS NPs. TEM analysis revealed the formation of well-dispersed CZTS NPs that were ~5-10nm in size. The sodium dodecyl sulfate surfactant played a key role in the formation of the CZTS NPs. The optical absorption studies revealed that the CZTS NPs had an optical band gap of 1.85eV, which is favorable for photovoltaic applications. The synthesized CZTS NPs could be used in the form of ink, which could be used to directly coat large area thin film solar cells. Moreover, the probable reaction mechanism for the formation of surfactant assisted CZTS NPs is proposed in present report. © 2015 Elsevier Ltd.

Patil V.L.,Commerce and Education College | Vanalakar S.A.,Commerce and Education College | Vanalakar S.A.,Chonnam National University | Kamble A.S.,Chonnam National University | And 3 more authors.
RSC Advances | Year: 2016

Novel hierarchical nanostructures of metal oxides have enormous potential in various applications. In this report, novel nanostructured maize-like ZnO was synthesized via a facile and economical modified successive ionic layer adsorption and reaction (M-SILAR) method and subsequent heat treatment at 300 °C for 30 min as a highly-sensitive NO2 gas sensor. The M-SILAR technique described uses two bath solutions instead of the conventionally used four bath solutions. Their structural, morphological, and optical properties have been thoroughly characterized using advanced techniques such as X-ray diffraction, field-emission scanning electron microscopy and photoluminescence spectroscopy. The obtained hexagonal wurtzite ZnO structure appears as the hierarchical maize corn-like morphology with nano-granules. The ZnO maize based sensor contains numerous active sites, which afford beneficial conditions for gas adsorption and diffusion. Moreover, the synthesized sensor was proven to be an excellent NO2 sensing material with high selectivity, superior sensitivity, and good response/recovery at relatively a low operating temperature. The peculiar structure of our sample, the preparation method and its nitrogen dioxide detection have wide application prospects. © 2016 The Royal Society of Chemistry.

Bhat T.S.,Shivaji University | Vanalakar S.A.,Commerce and Education College | Devan R.S.,University of Pune | Mali S.S.,Chonnam National University | And 5 more authors.
Journal of Materials Science: Materials in Electronics | Year: 2016

Thin films of Lead Selenide (PbSe) having compact nanoarchitectures were synthesized by a facile and cost-efficient successive ionic layer adsorption and reaction (SILAR) technique. The structural, morphological, optical and compositional properties were studied using X-ray diffraction (XRD), Field emission scanning electron microscopy (FESEM), Transmission electron microscopy (TEM), UV–vis spectrophotometer, and X-ray photoelectron spectroscopy (XPS) techniques. Moreover, the effect of SILAR cycles on the morphology of PbSe thin films was investigated. XRD patterns revealed the formation of crystalline PbSe with the cubic crystal structure. FESEM images show shape evolution from nanoparticulate to merged pyramidal—like structure with variation in size from ~200 to 430 nm. The optical direct band gap energy of PbSe were varies from 1.32 to 1.20 eV with the increase in deposition cycles. The HRTEM and SAED results show the crystalline nature of the sample which is in good agreement with the XRD. The electrical characterizations were performed in order to obtain the ohmic behavior in the metal–semiconductor interface. The deposited thin films show a good ohmic behavior. © 2016, Springer Science+Business Media New York.

Vanalakar S.A.,Commerce and Education College | Vanalakar S.A.,Chonnam National University | Patil V.L.,Commerce and Education College | Harale N.S.,Shivaji University | And 5 more authors.
Sensors and Actuators, B: Chemical | Year: 2015

Metal oxide gas sensors are promising devices that are widely used to detect various gases at moderate temperatures. In this study, nitrogen di-oxide (NO2) sensors were fabricated using zinc oxide (ZnO) nanorod arrays. ZnO nanorod arrays (ZNAs) with various rod lengths were deposited using a wet chemical route with zinc acetate as a precursor. The structural and surface morphological properties of the ZNAs were investigated using X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM), respectively. The XRD patterns showed ZNAs with wurtzite crystal structures that were preferentially oriented in the (0 0 2) direction. The intensity of the (0 0 2) plane was found to vary with the length of the nanorods. FESEM micrographs show that the ZNAs had a vertical alignment perpendicular to the substrate, and the diameter and length of the nanorods increased as the nanorod deposition time was increased. The gas sensing performance was studied as a function of the nanorod length, operating temperature, time and gas concentration. The length and inter-rod space was observed to play a crucial role in determining the gas sensing performance of the devices. ZNA gas sensors deposited for 9 h and operating at a temperature of 175 °C were able to detect NO2 at a concentration of 100 ppm with a high sensitivity of 3100%. © 2015 Elsevier B.V. All rights reserved.

Wandre T.M.,Shivaji University | Gaikwad P.N.,Shivaji University | Tapase A.S.,Shivaji University | Garadkar K.M.,Shivaji University | And 4 more authors.
Journal of Materials Science: Materials in Electronics | Year: 2016

The nanocomposites of TiO2–CeO2 are synthesized by a simple and cost-effective sol–gel method with cetyl trimethyl ammonium bromide (cationic surfactant) as capping agent at 500 °C. The X-ray diffraction analysis revealed phase purity of synthesized product. The X-ray photoelectron spectroscopy showed Ti4+ oxidation state of Ti element while Ce element was exist as a mixture of Ce3+ and Ce4+ oxidation state. The UV–Vis diffuse reflectance spectra clearly indicate the positive alteration in the optical response of TiO2 nanoparticles by the introduction of CeO2 nanoparticles. Scanning electron microscopic study revealed the formation of nanoclusters of spherical particles with uniform size distribution. Energy dispersive X-ray analysis confirmed the elemental composition. Fourier transform infrared spectroscopy analysis confirmed the presence of Ti–O–Ti stretching modes in the range of 900–400 cm−1. Photoluminescence spectroscopy was used to study the rate of recombination and transfer behaviors of photoexcited electron–hole pairs in the nanocomposites. Further, the photocatalytic activity of pure TiO2 nanoparticles and nanocomposite of TiO2 was studied using methyl orange. The TiO2:CeO2 nanocomposites exhibit high dye degradation compare with pure TiO2 nanoparticles. The composite TiO2:CeO2 (7:3) shows highest photocatalytic degradation of methyl orange dye in UV (60 min) and sunlight (90 min). © 2015, Springer Science+Business Media New York.

Loading Commerce and Education College collaborators
Loading Commerce and Education College collaborators