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Babar A.R.,Shivaji University | Shinde S.S.,Shivaji University | Moholkar A.V.,Gopal Krishna Gokhale College | Bhosale C.H.,Shivaji University | And 2 more authors.
Journal of Alloys and Compounds | Year: 2011

Transparent conductive thin films of nanocrystalline Sb:SnO2 have been deposited onto preheated glass substrates by using spray pyrolysis technique. The effect of the solution molarity on structural, morphological, optoelectronic properties of Sb:SnO2 films has been investigated. XRD study reveals that films are polycrystalline with tetragonal crystal structure having average crystallite size about 20 nm. The compact and homogeneous grains are seen in FESEM images. The BEs of Sn 3d5/2 for all samples show the Sn4+ bonding state for SnO2. The BEs of Sb 3d 5/2 are in the range of 530.6-530.9 eV, indicating that all antimony detected is in a pentavalent state (Sb5+). Transparency of films in the visible region decreases with increase in precursor concentration. Photoluminescence study shows the strong violet and weak orange emission. The sensing properties of the Sb:SnO2 films for acetone, ethanol and LPG with operating temperature and gas concentration have been investigated. © 2010 Elsevier B.V. All rights reserved.

Babar A.R.,Shivaji University | Shinde S.S.,Shivaji University | Moholkar A.V.,Gopal Krishna Gokhale College | Moholkar A.V.,Chonnam National University | Rajpure K.Y.,Shivaji University
Journal of Alloys and Compounds | Year: 2010

Nanocrystalline tin oxide (SnO2) powders were synthesized by chemical co-precipitation method using stannic chloride pentahydrate (SnCl 4·5H2O) precursor in aqueous medium. The influence of sintering temperatures on the crystalline structure, morphological, electrical, dielectric and XPS properties has been studied. X-ray diffraction study reveals that sintered powder which exhibits tetragonal crystal structure and both crystallinity as well as crystal size increase with increase in temperature. The nature of species of various absorption bonds viz. Sn-O, O-Sn-O and O-H involved in sintered SnO2 samples has been studied using FTIR technique. The morphological studies reveal randomly arranged grains with compact nature and grain size increases with sintering temperature. Measurements of electrical properties show relatively lower resistivity (≈10 2-103 Ω cm) and higher dielectric constant at 400 °C than other sintering temperatures. The compositional analysis and electronic behavior of SnO2 nanoparticles is studied using X-ray photoelectron spectroscopy. The symmetric spin orbit splitting of Sn 3d 5/2 ground state and Sn 3d3/2 excited states is observed with sintering temperature while O 1s is recognized with O2- state. © 2010 Elsevier B.V.All rights reserved.

Shinde S.S.,Shivaji University | Moholkar A.V.,Gopal Krishna Gokhale College | Moholkar A.V.,Chonnam National University | Kim J.H.,Chonnam National University | Rajpure K.Y.,Shivaji University
Surface and Coatings Technology | Year: 2011

Thin films of aluminium incorporated Fe2O3, synthesized by simple chemical spray pyrolysis on to glass substrates using aqueous solutions of analytical reagent grade ferric trichloride and aluminium nitrate as precursors. The influence of aluminium doping on to morphological properties, contact angle, X-ray photoelectron spectroscopy, photoluminescence and thermal conductivity properties have been investigated. The preparative parameters have been optimized to obtain good quality thin films which are uniform and well adherent to the substrate. The FE-SEM and AFM micrographs depict the films are compact and homogeneous (spindle-shaped hematite nanostructures) with varying grain sizes (average grain size ~20-60nm). Contact angle measurement show the films are hydrophobic in nature. The chemical composition and valence states of constituent elements in Fe2O3 are analyzed by X-ray photoelectron spectroscopy. The excitonic strong violet emission has been observed in photoluminescence. The specific heat and thermal conductivity study shows the phonon conduction behavior is dominant in these polycrystalline films. We studied interparticle interactions like grains, grain boundary effects using complex impedance spectroscopy. © 2010 Elsevier B.V.

Shin S.W.,KAIST | Ra Kang S.,Chonnam National University | Ho Yun J.,Korea Institute of Energy Research | Moholkar A.V.,Chonnam National University | And 4 more authors.
Solar Energy Materials and Solar Cells | Year: 2011

The effects of different annealing conditions such as atmospheres, temperatures and times on the structural, morphological and optical properties of ZnS thin films prepared on ITO coated glass substrates by chemical bath deposition were studied. Aqueous solutions of zinc acetate and thiourea were used as precursors along with stable complexing agents, such as Na 2EDTA and Na3-citrate, in an alkaline medium. X-ray diffraction patterns showed that the as-deposited and as-annealed ZnS films had an amorphous structure or poor crystallinity below the optimized annealing conditions of 500 °C and 60 min with the exception of the films annealed in N2H2S annealing atmosphere. The ZnS thin films annealed in N2H2S atmosphere for 1 h at 500 °C showed three sharp peaks for the (1 1 1), (2 2 0) and (1 1 3) planes of polycrystalline cubic ZnS without any unwanted secondary ZnO phases. X-ray photoelectron spectroscopy revealed ZnOH and ZnS bonding in the as-deposited ZnS thin film. However, the ZnS thin films annealed at 500 °C showed ZnS bonding regardless of the annealing atmosphere. The sharp absorption edge and band gap energy of the as-deposited and as-annealed ZnS thin films varied from 295 to 310 nm and 3.5 to 3.89 eV, respectively. © 2010 Elsevier B.V. All rights reserved.

Chavan H.V.,ASP College | Narale D.K.,Gopal Krishna Gokhale College
Comptes Rendus Chimie | Year: 2013

An efficient solvent-free synthesis of various 2,4,5-triaryl imidazoles and 1,2,4,5-tetraaryl imidazoles has been developed using silica chloride as a heterogeneous catalyst. The present methodology offers several advantages, such as excellent yields, shorter reaction times, economic availability, and reusability of catalyst. © 2013 Académie des sciences.

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