Radiation and Photochemistry Division

BARC, India

Radiation and Photochemistry Division

BARC, India
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Shinde S.K.,Shivaji University | Dubal D.P.,Shivaji University | Ghodake G.S.,Dongguk University | Lee D.S.,Kyungpook National University | And 3 more authors.
Materials Letters | Year: 2014

Cd1-XFeXSe thin films were electrodeposited onto fluorine doped tin oxide coated conducting glass (FTO) and stainless steel (SS) substrates at various bath compositions with X=0.1 to 0.5 in an aqueous electrolytic bath containing CdSO4, FeSO4 and SeO 2. The effects of different compositions on physico-chemical properties of Cd1-XFeXSe thin films have been systematically investigated. The X-ray diffraction (XRD) analysis reveals the polycrystalline in nature of Cd1-XFeXS thin films. Field emission scanning electron microscopy (FE-SEM) micrographs shows the variation in the nanostructure with varying compositions. The Cd1-XFeXSe thin films exhibited the water contact angles in hydrophilic range. Optical absorption measurements are used to estimate the band gap value of Cd1-XFeXSe thin films deposited at various bath compositions. The dramatic changes in surface morphology, as a consequence of different composition of Fe in CdSe matrix, significantly alter the conversion efficiency of Cd1-XFe XSe films. © 2014 Elsevier B.V. All rights reserved.

Maiti N.,Radiation and Photochemistry Division | Thomas S.,High Pressure and Synchrotron Radiation Physics Division | Debnath A.,Bhabha Atomic Research Center | Kapoor S.,Radiation and Photochemistry Division
RSC Advances | Year: 2016

This is the first report on the surface-enhanced Raman scattering (SERS) and X-ray photoelectron spectroscopic (XPS) studies of taurine adsorbed on the surface of silver nanoparticles. Taurine, the sulphonic acid analogue of β-alanine participates in numerous biological and physiological functions in the human body and is a potent antioxidant. The interpretation of the SERS spectrum based on the "surface selection rules", XPS studies and DFT calculations has clearly indicated that the gauche tautomer of taurine is predominant on the silver nanoparticle surface. Taurine is directly bound to the silver surface through the sulphonate group along with interactions from the NH2 group that lies in close proximity to the metal surface. The binding of taurine through the oxygen atoms of the sulphonate group is confirmed by the XPS studies which show the presence of 71% Ag-O in taurine functionalized silver nanoparticles. © 2016 The Royal Society of Chemistry.

Kawade V.A.,University of Pune | Kumbhar A.S.,University of Pune | Naik D.B.,Radiation and Photochemistry Division | Butcher R.J.,Howard University
Dalton Transactions | Year: 2010

Complexes of the type [Co(pic)2(LL)], where pic = picolinate; LL = (H2O)2 (1), 2,2′-bipyridine (bpy) (2), 1,10-phenanthroline (phen) (3) and dipyrido[3,2-a:2′,3′-c]phenazine (dppz) (4) have been synthesized and characterized by elemental analysis, IR, UV-visible and 1H-NMR spectroscopy. Complex 2 crystallized from a mixture of chloroform and methanol in orthorhombic crystal system, space group Iba2. Complex 3 crystallizes from chloroform in monoclinic crystal system, space group P121/a1 and in a mixture of water and methanol in triclinic crystal system, space group P1. Co(II)/Co(iii) oxidation potentials have been determined by cyclic voltammetry and the concomitant spectral changes measured by spectroelectrochemistry. The reactions of one electron reducing (e -aq, (CH3)2COH and CO 2-) and one electron oxidizing (OH) radicals with the above metal complexes have been studied by pulse radiolysis. The rate constants for the reaction of e-aq and OH radicals with the complexes are of the order of 1010 and 109 dm3 mol-1 s-1, respectively. The reaction of hydrated electron (e-aq) with the complexes results in the formation of a ligand radical anion species which decays by either protonation of ligand or reduction of metal by intramolecular electron transfer resulting in cobalt(i) species. The reaction of OH radical forms the OH-adducts of the ligand. © 2010 The Royal Society of Chemistry.

Thombare J.V.,Shivaji University | Rath M.C.,Radiation and Photochemistry Division | Han S.H.,Hanyang University | Fulari V.J.,Shivaji University
Journal of Semiconductors | Year: 2013

Polypyrrole (PPy) thin films were deposited on stainless steel and ITO coated glass substrate at a constant deposition potential of 0.8 V versus saturated calomel electrode (SCE) by using the electrochemical polymerization method. The PPy thin films were deposited at room temperature at various monomer concentrations ranging from 0.1 M to 0.3 M pyrrole. The structural and optical properties of the polypyrrole thin films were investigated using an X-ray diffractometer (XRD), FTIR spectroscopy, scanning electron microscopy (SEM), and ultraviolet - visible (UV - vis) spectroscopy. The XRD results show that polypyrrole thin films have a semi crystalline structure. Higher monomer concentration results in a slight increase of crystallinity. The polypyrrole thin films deposited at higher monomer concentration exhibit high visible absorbance. The refractive indexes of the polypyrrole thin films are found to be in the range of 1 to 1.3 and vary with monomer concentration as well as wavelength. The extinction coefficient decreases slightly with monomer concentration. The electrochemically synthesized polypyrrole thin film shows optical band gap energy of 2.14 eV. © 2013 Chinese Institute of Electronics.

Thombare J.V.,Shivaji University | Rath M.C.,Radiation and Photochemistry Division | Han S.H.,Hanyang University | Fulari V.J.,Shivaji University
Journal of Semiconductors | Year: 2013

The optical properties of polypyrrole (Ppy) thin films upon 2 MeV electron beam irradiation changes with different doses. The induced changes in the optical properties for Ppy thin films were studied in the visible range 300 to 800 nm at room temperature. The optical band gap of the pristine Ppy was found to be 2.19 eV and it decreases up to 1.97 eV for a 50 kGy dose of 2 MeV electron beam. The refractive index dispersion of the samples obeys the single oscillator model. The obtained results suggest that electron beam irradiation changes the optical parameters of Ppy thin films. © 2013 Chinese Institute of Electronics.

Chougale U.M.,Shivaji University | Han S.H.,Hanyang University | Rath M.C.,Radiation and Photochemistry Division | Fular V.J.,Shivaji University
Materials Physics and Mechanics | Year: 2013

Herein we report electrochemical synthesis of the silver selenide (Ag 2Se) thin films using simple and economical electrodeposition method in potentiostatic mode at room temperature (~ 27 °C). Growth of rhombohedral Ag2Se nanocrystals having size 63 to 75 nm were observed in (201) direction. Band gap energy of Ag2Se decreased from 1.3 eV to 1.1 eV and contact angle increases from 58° to 74° with increase in bath concentration from 3 to 5 mM. A possible mechanism for the growth and stress of compact granular Ag2Se nanocrystals is discussed with DEHI technique. Compared with previous methods, present method shows simple and easiest way to synthesize nanosized Ag2Se particles in one step. © 2013, Institute of Problems of Mechanical Engineering.

Lohar G.M.,Shivaji University | Jadhav S.T.,Shivaji University | Takale M.V.,Shivaji University | Patil R.A.,National Dong Hwa University | And 3 more authors.
Journal of Colloid and Interface Science | Year: 2015

The Fe2+ doped ZnSe nanorods are synthesized using simple potentiostatic mode of electrodeposition on the ITO substrate. In order to study the doping effect of Fe2+ in ZnSe, varied the doing percent such as 0.5%, 1%, 1.5%. These films are characterized for structural, compositional, morphological, optical and electrochemical properties using the X-ray diffraction study (XRD), X-ray photoelectron spectroscopy, field emission scanning electron microscopy, UV-vis spectroscopy and electrochemical spectroscopy. Along with these Raman spectroscopy and photoluminescence spectroscopy have been studied for understanding the characteristics vibrations of ZnSe and luminescence of ZnSe nanorods. FE-SEM shows the nanorods like morphology. Photoelectrochemical cell performance studied using the J-V measurement and it shows the maximum efficiency at 1% Fe2+ doped ZnSe nanorods. The observed maximum efficiency of Fe2+ doped ZnSe nanorods is 0.32%. © 2015.

Naik A.B.,Karnatak University | Naik L.R.,Karnatak University | Kadadevarmath J.S.,Karnatak University | Pal H.,Radiation and Photochemistry Division | Rao V.J.,Indian Institute of Chemical Technology
Journal of Photochemistry and Photobiology A: Chemistry | Year: 2010

Fluorescence quenching of anthrylvinyl acetate by carbon tetrachloride (CCl4) was carried out in both polar and non-polar solvents at room temperature to understand the role of quenching mechanism. The negative deviation in normal Stern-Volmer (S-V) plots was observed in almost all solvents used for λex 345 nm, 365 nm and 385 nm. The bimolecular quenching rate constant (kq) estimated using the measured values of quenching constants and decay times were found to be dependent on the polarity of the solvent. Further, it is found that quenching efficiency increases with increasing polarity of the solvent. The negative deviations from the normal Stern-Volmer (S-V) plots shown in the fluorescence quenching of anthrylvinyl acetate by carbon tetrachloride is interpreted in terms of the existence of different conformers of the solute in the ground-state. Fluorescence decay of the solute before quenching showed bi-exponential behavior and the analysis yielded two decay components, respectively, in the range 2.11-7.22 ns and 5.17-12 ns in all solvents except n-propanol and methanol. Based on the steady state and fluorescence lifetime measurements emission band I (408 nm) is assigned due to locally (LE) excited state (Trans form), band II (430 nm) due to isomer state of Cis form. © 2010 Elsevier B.V. All rights reserved.

Verma S.,Radiation and Photochemistry Division | Aute S.,CSIR - National Chemical Laboratory | Das A.,CSIR - National Chemical Laboratory | Ghosh H.N.,Radiation and Photochemistry Division
Journal of Physical Chemistry B | Year: 2015

Hydrogen bonding interaction plays an essential role in the early phases of molecular recognition and colorimetric sensing of various anions in aprotic media. In this work, the host-guest interaction between fac-[Re(CO)3Cl(L)] with L = 4-([2,2′-bipyridin]-4-yl)phenol and fluoride ions is investigated for the hydrogen bond dynamics and the changing local coordination environment. The stoichiometric studies using 1H NMR and ESI-MS spectroscopies have shown that proton transfer in the H-bonded phenol-fluoride complex activates the dissociation of the CO ligand in the Re(I) center. The phenol-to-phenolate conversion during formation of HF2 - ion induces nucleophilic lability of the CO ligand which is probed by intraligand charge transfer (ILCT) and ligand-to-metal charge transfer (LMCT) transitions in transient absorption spectroscopy. After photoexcitation, phenol-phenoxide conversion rapidly equilibrates in 280 fs time scale and the ensuing excited state [ReII(bpy•- - phenolate¯) (CO)3Cl]∗ undergoes CO dissociation in the ultrafast time scale of ∼3 ps. A concerted mechanism of hydrogen cleavage and coordination change is established in anion sensing studies of the rhenium complex. © 2015 American Chemical Society.

Lohar G.M.,Shivaji University | Shinde S.K.,Shivaji University | Rath M.C.,Radiation and Photochemistry Division | Fulari V.J.,Shivaji University
Materials Science in Semiconductor Processing | Year: 2014

The present investigation describes that the iron (Fe) doped ZnSe hexagonal nanorods were successfully synthesized via chemical synthesis specifically galvanostatic mode of electrodeposition and addition of Fe in order to improve the PEC performance of ZnSe electrodes using a galvanostatic mode. These crystalline Fe doped ZnSe hexagonal nanorods electrodes are characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and optical properties, such as UV-vis spectroscopy, photoluminescence spectroscopy, electrochemical impedance spectroscopy (EIS), Raman spectroscopy and photoelectrochemical properties. It is seen that at 5% Fe doped ZnSe hexagonal nanorods show the open circuit voltage (Voc) was 100 mV, and short circuit current (Isc) was 110 μA. The observed fill factor and efficiency were found to be 44% and 0.15%, respectively. © 2014 Elsevier Ltd.

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