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Ekar S.U.,Baburaoji Gholap College | Khollam Y.B.,Anantrao Pawar College | Koinkar P.M.,Tokushima University | Mirji S.A.,CSIR - National Chemical Laboratory | And 3 more authors.
Modern Physics Letters B | Year: 2015

Present study reports the biochemical synthesis of silver nanoparticles (Ag-NPs) from aqueous medium by using the extract of medicinal mushroom Ganoderma, as a reducing and stabilizing agents. The Ag-NPs are prepared at room temperature by the reduction of Ag+ to Ag in aqueous solution of AgNO3. The resultant particles are characterized by using UV-visible spectroscopy, Fourier transform infrared (FTIR) spectroscopy and transmission electron microscopy (TEM) measurement techniques. The formation of Ag-NPs is confirmed by recording the UV-visible absorption spectra for surface plasmon resonance (SPR) where peak around 427 nm. The prominent changes observed in FTIR spectra supported the reduction of Ag+ to Ag. The morphological features of Ag-NPs are evaluated from HRTEM. The spherical Ag-NPs are observed in transmission electron microscopy (TEM) studies. The particle size distribution is found to be nearly uniform with average particle size of 2 nm. The Ag-NPs aged for 15, 30, 60 and 120 days showed no profound effect on the position of SPR peak in UV-visible studies, indicating the protecting/capping ability of medicinal mushroom Ganoderma in the synthesis of Ag-NPs. © 2015 World Scientific Publishing Company.


Shelke P.N.,Baburaoji Gholap College | Khollam Y.B.,Anantrao Pawar College | Gunjal S.D.,University of Pune | Koinkar P.M.,Tokushima University | And 2 more authors.
Modern Physics Letters B | Year: 2015

Present communication reports the LPG and NH3 sensing properties of Co3O4 films prepared on throughly cleaned stainless steel (SS) and copper (CU) substrates by using DC electrochemical deposition method followed by air annealing at 350°C/2 h. The resultant films are characterized by using X-ray diffraction (XRD), Raman spectroscopy and scanning electron microscopy (SEM). The LPG and NH3 gas sensing properties of these films are measured at room temperature (RT) by using static gas sensing system at different concentrations of test gas ranging from ~25 ppm to 350 ppm. The XRD and Raman spectroscopy studies clearly indicated the formation of pure cubic spinel Co3O4 in all films. The LPG and NH3 gas sensing properties of films showed (i) the increase in sensitivity factor (S.F.) with gas concentrations and (ii) more sensibility to LPG as compared to NH3 gas. In case of NH3 gas (conc. ~150 ppm) and LPG gas (conc. ~60 ppm) sensing, the maximum S.F. = 270 and 258 are found for the films deposited on CU substrates, respectively. For all films, the response time (3-5 min.) is found to be much higher than the recovery time (30-50 sec). For all films, the response and recovery time are found to be higher for LPG as compared to NH3 gas. Further, repeatability- reproducibility in gas sensing properties is clearly noted by analysis of data for number of cycles recorded for all films from different set of depositions. © 2015 World Scientific Publishing Company.


Sarode M.T.,Mahatma Phule A S C College | Khollam Y.B.,Anantrao Pawar College | Gunjal S.D.,University of Pune | Shelke P.N.,Baburaoji Gholap College | And 3 more authors.
Advanced Science Letters | Year: 2016

The present communication reports the deposition of nanocrystalline, pure anatase TiO2 films by using the sol–gel dip coating method on glass substrates. The as-deposited films are annealed at moderate temperatures of 300, 400 and 500 °C for 2 hr to obtain the well crystalline single anatase phase TiO2films. The films are characterized by using X-ray diffraction (XRD), Raman spectroscopy, high resolution transmission electron microscopy (HRTEM), UV-Visible spectroscopy and thickness measurement. The characterization studies revealed that resultant films are nanocrystalline (average XRD crystallite size ∼17 nm, and average HRTEM particle size ∼20 nm), pure and having single anatase tetragonal phase. With increasing the annealing temperature, thickness is found to be decreasing, whereas % transmittance and absorption coefficient are noted to be increasing. The anatase TiO2films prepared in present work might be useful for the dye sensitized solar cells generation. © 2016 American Scientific Publishers. All rights reserved.


Shelke P.N.,Baburaoji Gholap College | Khollam Y.B.,Anantrao Pawar College | Gunjal S.D.,University of Pune | Gunjal S.D.,Haribhai V Desai College | And 4 more authors.
Advanced Science Letters | Year: 2016

The present work reports the preparation of pure cubic-spinel Co3O4films with better optical properties on thoroughly cleaned copper substrates by using electrochemical deposition technique with Co(NO3)26H2O as Co precursor. The resultant films are characterized by using XRD, UV-Visible spectroscopy, FTIR spectroscopy and SEM techniques. The characterization results revealed that the resultant films are constituted with Co3O4particles (sizes in the range of 1–3 μm) with cubic-spinel symmetry. The resultant films showed the better values of absorptance (α)= 0.97 and emittance (ε) = 0.05 as compared to the reported data. The band gap energy values of resultant are Co3O4films are found to be in range of 1.189–1.400 eV. The films prepared in the present work might be useful for solar absorption selective coating applications. © 2016 American Scientific Publishers. All rights reserved.


Gunjal S.D.,University of Pune | Khollam Y.B.,Anantrao Pawar College | Udawant R.R.,University of Pune | Jadkar S.R.,University of Pune | And 3 more authors.
Proceedings of the International Conference on "Advanced Nanomaterials and Emerging Engineering Technologies", ICANMEET 2013 | Year: 2013

The p-CdTe films are prepared on thoroughly cleaned glass substrates by using ultrasonic spray pyrolysis techniques in-situ reducing atmosphere with air-ambient at 548 and 573 K. The resultant films are characterized by using X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), energy dispersive X-ray (EDAX) analysis, UV-Visible spectroscopy and Hall measurement set-up. The characterization studies revealed crystallization of the main p-CdTe phase with minor oxidation corresponding to TeO2 in resultant films. The uniform size distribution of spherical particles with average particle size = 0.2 μm is noted from SEM studies. The optical properties are found to be absorbance (α) = 0.80 and band gap (E g) = 1.46 eV for the films prepared at 573 K. The less oxidation at higher processing temperature realized in XRD and EDAX studies might be due to higher crystallization rate of p-CdTe dominating the oxidation. The Hall coefficient, RH = 0.0205 × 104 cm3/C, resistivity, r = 0.5812 × 102 ω-cm and negative current value in Hot probe experiment indicated p-type semiconductor nature of resultant films processed at 573 K. The higher concentration (n), and less mobility (μ) of majority charge carriers for the films processed at 573 K might be due to less oxidation at higher temperature. © 2013 IEEE.


Gunjal S.D.,University of Pune | Khollam Y.B.,Anantrao Pawar College | Jadkar S.R.,University of Pune | Shripathi T.,University Campus | And 5 more authors.
Solar Energy | Year: 2014

The present communication reports the structural, optical and electrical properties of p-CdTe films deposited by using spray pyrolysis technique on thoroughly cleaned sodalime glass substrates at 350°C in inert N2 atmosphere. The films were characterized by using XRD, Raman spectroscopy, XPS, thickness profiler, SEM, EDAX and UV-Visible spectroscopy and Hall parameters measurement. The structural studies showed the formation of pure cubic CdTe in resultant films with crystallite size=32nm. The texture coefficient TC(hkl) indicated preferential orientation of films along [311] and [511] directions. The SEM image showed almost spherical granules with average size of 0.25μm. From UV-Visible spectral data, the maximum absorbance and direct band gap obtained using Tauc plot are found to be 0.94 and Eg=1.44eV respectively for films having thickness, t=3.2μm. The Hot probe experiment, Hall coefficient RH=1.478×103cm3/C, and resistivity ρ=2.228×101Ωcm confirmed the p-type semiconducting behavior of CdTe films. The mobility of majority charge carriers - holes is found to be μ=6.63×101cm2/Vs. The films processed using present work can be treated as possible p-type candidate for fabrication of hetero-junction solar cell. © 2013 Elsevier Ltd.


More P.S.,Institute of Science | Khollam Y.B.,Anantrao Pawar College | Ghuge C.S.,Institute of Science | Sonone R.S.,Institute of Science
Asian Journal of Chemistry | Year: 2013

A miniaturized, non-destructive, non-toxic porous silicon based sensor is investigated as a sensing material to detect leaf moisture at very low moisture concentration. The porous silicon layer (pore size = 10 nm) is obtained by electrochemical etching of p-type silicon wafer. The polyethylene oxide modified porous silicon is obtained by dip-coating method. The difference in sensitivity in green (SF = 55) and yellow (SF = 40) hibiscus leaves indicated that the moisture content in green leaf is more as compared to yellow leaf. In this study, we intend to demonstrate moisture representing the influence of the technological parameters on the porous structure and the device sensitivity. © Asian Journal of Chemistry 2013.


Gunjal S.D.,University of Pune | Khollam Y.B.,Anantrao Pawar College | Arote S.A.,University of Pune | Shelke P.N.,BaburaojiGholap College | And 3 more authors.
Advanced Science Letters | Year: 2014

The present work is focused on the deposition of conducting and transparent fluorine (F)-doped tin oxide, SnO2:F (FTO) films by using spray pyrolysis technique at different substrate temperature (Ts) varying from 400 to 525 °C in a step of 25 °C and stannic chloride (SnCl4 • 5H2O) and ammonium fluoride (NH4F) as precursor materials. The structural, optical and electrical properties of resultant FTO films are investigated as a function of substrate temperature (Ts). The resultant FTO films are characterized by using X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), energy dispersive analysis of X-rays, surface profilometer, UV-Visible spectroscopy and Hall Effect measurement. The structural analysis indicated the preferred orientation along [200] direction with pure tetragonal symmetry in the resultant FTO films. The crystallinity of films is noted to be improved with increasing TS. The values of thickness of FTO films are observed to be between 208 nm and 845 nm. The SEM results indicated nanocrystalline nature of FTO films with average particle size in the range of 18-27 nm. The Hall Effect measurements showed the lowest sheet resistance = 16.04 Ω and better mobility of majority charge carriers (μ) = 22.04 cm2/Vs for the films deposited at 425 °C. The UV-visible spectroscopic studies showed the highest average transmittance = 88.92% in the visible region (λ = 400 to 800 nm) for the films deposited at 425 °C. All above results indicates that FTO films deposited in present work are useful in solar cell device fabrication applications. © 2014 American Scientific Publishers. All rights reserved.


Sarode M.T.,Commerce and Science College | Khollam Y.B.,Anantrao Pawar College | Jadkar S.R.,University of Pune | Kale B.B.,CMET - Photonics And Advanced Materials Laboratory | Mohite K.C.,University of Pune
Solar Energy | Year: 2014

Herein, we report the thickness dependent optical and eosin-Y dye sensitized solar cell (DSSC) characteristics of nanocrystalline anatase (nc-a) TiO2 films deposited on indium tin oxide (ITO) substrates by using sol-gel dip-coating method with C12H28O4Ti (TTIP) (0.05 and 0.10M) as Ti-precursor. The as-deposited films were heated at 400°C/2h in air. The XRD and Raman spectroscopy characterization studies revealed the formation of pure single anatase TiO2 phase in resultant films. The HRTEM studies reflected uniform size distribution of spherical TiO2 nanoparticles (average size ~20nm) with crystalline grains of diameters=15-20nm in a structured matrix. This is consistent with XRD results of crystallite size=10-25nm. A profound effect of variation of film thickness on optical and eosin-Y sensitized photovoltaic characteristics of nc-a TiO2 films is observed. With increasing the film thickness, the % optical transmission (T), absorption coefficient (α), refractive index (n) and optical conductivity (σopt) are found to be decreasing whereas, porosity ratio (% P) and photoconversion efficiency (η) are found to be increasing. The optical indirect band gap is found to be between 3.20 and 3.21eV. The better photovoltaic performance: open-circuit voltage of 0.554V, short circuit current of 1.291mA, fill factor of 41.57% and conversion efficiency (η) of 1.10% is obtained for eosin-Y DSSC using redox polyiodide (1M KOH+1M KI+0.5M iodine) electrolyte in actonitrile. © 2013 .


Sarode M.T.,Mahatma Phule Asc College | Khollam Y.B.,Anantrao Pawar College | Jadkar S.R.,University of Pune | Kale B.B.,CMET - Photonics And Advanced Materials Laboratory | Mohite K.C.,University of Pune
Asian Journal of Chemistry | Year: 2013

Different thickness of dye sensitized solar cells of TiO2 thin films prepared by modified sol-gel method with Eosin-Y and Rose Bengal dyes are investigated in present communication. As deposited films 1, 3 and 5 layer coating were annealed 400 °C/2 h. The resultant films were characterized by using XRD, Raman spectroscopy, SEM, TEM and UV-visible spectroscopy. The structural studies revealed the evolution of pure anatase TiO2 phase in resultant films. The morphological studies with SEM indicated nearly uniform size distribution of spherical agglomerates in resultant films. The TEM studies indicated nanocrystalline state of films (average particle size ~1 25 nm) consistent with XRD results of crystallite size = 20-30 nm. The better optical properties: indirect band gap energy, absorbance coefficient, transmittance, refractive index and porosity ratio are 3.22 eV, 2.8 × 104 cm-1, 86 %, 2.02 and 43.50 % respectively of the 5 layer coating film annealed at 400 °C/2 h. The better photovoltaic performance: VOC = 0.70 V, JSC = 1.82 mA/cm2, FF = 68.3 % and η = 0.87 % using Eosin-Y dye with polyiodide electrolyte are obtained for the dye sensitized solar cells of TiO2 films generated from 5 layer coated film annealed at 400 °C/2 h. The conversion efficiency increases with increasing thickness of film and it is greater for Eosin-Y than Rose Bengal dye. © Asian Journal of Chemistry 2013.

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