@article { ISI:000229664600004, title = {Electronic structure and ferromagnetism of polycrystalline Zn1-xCoxO (0 <= x <= 0.15)}, journal = {Solid State Communications}, volume = {134}, number = {10}, year = {2005}, month = {JUN}, pages = {665-669}, publisher = {PERGAMON-ELSEVIER SCIENCE LTD}, type = {Article}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND}, abstract = {

The electronic structure of polycrystalline ferromagnetic Zn1-x,CoxO (0.05 \<= x \<= 0.15) and the oxidation state of Co in it, have been investigated. The Co-doped polycrystalline samples are synthesized by a combustion method and are ferromagnetic at room temperature. XPS and optical absorption studies show evidence for Co2+ ions in the tetrahedral symmetry, indicating, substitution of Co2+ in the ZnO lattice. However, powder XRD and electron diffraction data shock the presence of Co metal in the samples. This give evidence to the fact that some Co2+ ion are incorporated in the ZnO lattice which gives changes in the electronic structure whereas ferromagnetism comes from the Co metal impurities present in the samples. (c) 2005 Elsevier Ltd. All rights reserved.

}, keywords = {Magnetically ordered materials, Optical properties, Semiconductors}, issn = {0038-1098}, doi = {10.1016/j.ssc.2005.03.013}, author = {Deka, Sasanka and Joy, Pattayil Alias} } @article { ISI:000244008300028, title = {Influence of surfactant on ZnO varistors}, journal = {Ceramics International}, volume = {33}, number = {2}, year = {2007}, month = {MAR}, pages = {289-291}, publisher = {ELSEVIER SCI LTD}, type = {Article}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND}, abstract = {

ZnO varistors with and without surfactant such as sodium dodecyl sulphate (SIDS) are prepared by nitrate-combustion process. The samples were identically heat treated and sintered at 1000 degrees C for 12 h to study the influence of the surfactant on the nonlinear electrical properties of polycrystalline ZnO. It is observed that the nonlinear coefficient decreases marginally (alpha = 35) for samples prepared with surfactant, whereas breakdown field (E-B = 130 V/mm) decreased significantly. The corresponding parameters for the samples synthesized without surfactant are alpha = 45 and E-B = 400 V/mm. Hence, this method can be used for the manufacture of varistors with low to moderate breakdown fields. (c) 2005 Elsevier Ltd and Techna Group S.r.l. All rights reserved.

}, keywords = {Chemical synthesis, Semiconductors, X-ray methods, ZnO}, issn = {0272-8842}, doi = {10.1016/j.ceramint.2005.08.010}, author = {Dhage, S. R. and Navale, S. C. and Ravi, V.} } @article { ISI:000259420300006, title = {Facile synthesis and gas sensing properties of nanotriangular tin oxide}, journal = {Materials Letters}, volume = {62}, number = {28}, year = {2008}, month = {NOV}, pages = {4328-4331}, publisher = {ELSEVIER SCIENCE BV}, type = {Article}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

In the present study we report a simple and convenient chemical route using pentaerythritol as a structure-directing agent for the synthesis of crystalline nanotriangular SnO2. We propose the scheme for the formation of nanotriangular structures wherein the preliminary spherical nanocrystallites are formed due to the low surface energy associated with them. These spherical nanocrystallites grow into the various linear intermediate shapes like Y, bi and tripods, which finally lead to the triangles, pyramids and bipyramids. Such variation in the structure occurs due to the structure directing pentaerythritol. These polycrystalline SnO2 nanomaterials with structural peculiarities were tested for the gas sensing characteristics. Their response towards ethanol vapor, H-2 and LPG were investigated. It was found to exhibit high response towards ethanol vapors at the operating temperature of 250 degrees C. (C) 2008 Elsevier B.V. All rights reserved.

}, keywords = {Nanomaterials, Oxides, Semiconductors, sensors}, issn = {0167-577X}, doi = {10.1016/j.matlet.2008.07.021}, author = {Deshmukh, Rupali G. and Badadhe, Satish S. and Vaishampayan, Mukta V. and Mulla, Imtiaz S.} } @article { ISI:000262886200019, title = {Epitaxially grown zinc-blende structured Mn doped ZnO nanoshell on ZnS nanoparticles}, journal = {Materials Research Bulletin}, volume = {44}, number = {2}, year = {2009}, month = {FEB}, pages = {339-344}, publisher = {PERGAMON-ELSEVIER SCIENCE LTD}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND}, abstract = {

Zinc oxide in the bulk as well as in the nanocrystalline form is thermodynamically stable in the wurtzite structure. However, zinc oxide in the zinc-blende structure is more useful than that in the wurtzite structure due to its superior electronic properties as well as possibility of efficient doping. Therefore, zinc oxide shell is grown epitaxially on zinc sulphide core nanoparticles having zinc-blende structure. It is shown that doping of manganese could be achieved in zinc oxide nanoshell with zinc-blende structure. (C) 2008 Elsevier Ltd. All rights reserved.

}, keywords = {Chemical synthesis, Luminescence, Nanostructures, Semiconductors, X-ray diffraction}, issn = {0025-5408}, doi = {10.1016/j.materresbull.2008.05.015}, author = {Limaye, Mukta V. and Singh, Shashi B. and Date, Sadgopal K. and Gholap, Ramkrishna S. and Kulkarni, Sulabha K.} } @article { ISI:000262987800024, title = {Solid state synthesis and room temperature magnetic properties of iron phosphide nanoparticles}, journal = {Journal of Nanoparticle Research}, volume = {11}, number = {2}, year = {2009}, month = {FEB}, pages = {491-497}, publisher = {SPRINGER}, address = {VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS}, abstract = {

Room temperature magnetic properties have been achieved for nano-crystalline iron phosphide synthesized from the direct solid state reaction of iron chloride and tri-octylphosphine (TOP). The magnetization continuously increased with higher magnetic fields, indicating a super-paramagnetic behavior. It is observed that room temperature magnetism is possible for the material showing antiferromagnetic nature at low temperatures. In the present synthesis, TOP acted as a source of phosphorus as well as a surfactant. X-ray diffraction (XRD) studies revealed that the black powder is a mixture of FeP and Fe(2)P. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) showed elongated as well spherical particles. Energy dispersion X-ray analysis (EDAX) confirmed a non-stoichiometric iron phosphide. Presence of TOP was confirmed by infra-red (IR) spectroscopy, and thermo-gravimetric analysis (TGA) indicated about 6\% wt. loss due to presence of organics.

}, keywords = {Iron phosphide, Semiconductors, Solid state reaction, synthesis, XRD}, issn = {1388-0764}, doi = {10.1007/s11051-008-9458-0}, author = {Singh, N. and Khanna, P. K. and Joy, Pattayil Alias} } @article { ISI:000275170800011, title = {One-pot synthesis of oleic acid-capped cadmium chalcogenides (CdE: E = Se, Te) nano-crystals}, journal = {Journal of Nanoparticle Research}, volume = {12}, number = {1, SI}, year = {2010}, month = {JAN}, pages = {101-109}, publisher = {SPRINGER}, address = {VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS}, abstract = {

Surface-capped CdSe and CdTe nano-crystals (NCs) have been synthesized using cadmium acetate, oleic acid and respective tri-octylphosphine chalcogenide (TOPE; E = Se/Te) in diphenyl ether (DPE). Well-dispersed CdSe particles showed two absorption bands at the region of 431-34 and 458-60 nm in optical absorption study. A band-edge emission resulted at 515 nm with an excitation energy of 400 nm, in its photoluminescence (PL) spectrum. Similarly, UV-visible absorption study of CdTe revealed an absorption band at \< 700 nm. The broadened X-ray diffraction (XRD) pattern showed that at higher reaction temperature cubic CdSe but hexagonal CdTe can be obtained with crystallite size of \< 10 nm. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) revealed that agglomerated particles are of spherical nature. The inter-planar spacing in CdTe was measured to be 0.406 nm, a characteristic of (100) lattice plane in hexagonal CdTe. X-ray photoelectron spectroscopy (XPS) showed that CdSe NCs have better air stability stable than CdTe. Presence of organic moiety around the semiconductor particles was confirmed by infrared (IR) spectroscopy.

}, keywords = {Chemical synthesis, photoluminescence, Semiconductors, Surface capping}, issn = {1388-0764}, doi = {10.1007/s11051-008-9581-y}, author = {Khanna, P. K. and Rao, K. Srinivasa and Patil, K. R. and Singh, V. N. and Mehta, B. R.} } @article { ISI:000274839100053, title = {Synthesis and characterization of nickel selenide thin films deposited by chemical method}, journal = {Journal of Alloys and Compounds}, volume = {490}, number = {1-2}, year = {2010}, month = {FEB}, pages = {228-231}, publisher = {ELSEVIER SCIENCE SA}, address = {PO BOX 564, 1001 LAUSANNE, SWITZERLAND}, abstract = {

Nickel selenide thin films have been deposited using chemical bath method on non-conducting glass substrates in a tartarate bath containing nickel sulphate octahydrate, hydrazine hydrate, sodium seleno-sulphate in an aqueous alkaline medium. The grown films were uniform, well adherent and black in color. The films were characterized using X-ray diffraction, scanning electron microscopy, optical absorption and electrical measurements. The nickel selenide thin film revealed polycrystalline nature with hexagonal system. The direct optical band gap of the film was found to be 1.61 eV. Electrical resistivity of film was observed in the order of 10(3) (Omega cm) with p-type conduction mechanism. (C) 2009 Elsevier B.V. All rights reserved.

}, keywords = {Crystal growth, Semiconductors, Thin films, X-ray diffraction}, issn = {0925-8388}, doi = {10.1016/j.jallcom.2009.09.132}, author = {Hankare, P. P. and Jadhav, B. V. and Garadkar, K. M. and Chate, P. A. and Mulla, Imtiaz S. and Delekar, S. D.} } @article { ISI:000288529500015, title = {Role of lattice defects and crystallite morphology in the UV and visible-light-induced photo-catalytic properties of combustion-prepared TiO2}, journal = {Materials Chemistry and Physics}, volume = {126}, number = {3}, year = {2011}, month = {APR}, pages = {546-554}, publisher = {ELSEVIER SCIENCE SA}, address = {PO BOX 564, 1001 LAUSANNE, SWITZERLAND}, abstract = {

The physico-chemical, photo-physical and micro-structural properties responsible for the strikingly different photocatalytic behavior of combustion-prepared TiO2 (c.TiO2) and Degussa P25 (d.TiO2) samples are elucidated in this study. Electron microscopy and selected area electron diffraction micrographs revealed that the two samples exhibited different morphologies. The grains of c.TiO2 were spherical and comprised of 5-6 nm size primary particle. On the other hand, d.TiO2 consisted of large (0.5-3.0 mu m) size and irregular shape aggregates having primary particles of 15-40 nm cross-sectional diameter. The ESR study revealed that the presence of certain defect states in c.TiO2 helped in stabilization of O-. and Ti3+-OH type species during room-temperature UV-irradiation. No such paramagnetic species were however formed over d.TiO2 under similar conditions. C1s and Ti 2p XPS spectra provide evidence for the presence of some lattice vacancies in c.TiO2 and also for the bulk Ti4+ -\> Ti3+ conversion during its UV-irradiation. Compared to d.TiO2, c.TiO2 displayed considerably higher activity for discoloration of methyl orange but very poor activity for splitting of water, both under UV and visible light radiations. This is attributed to enhanced surface adsorption of dye molecules over c.TiO2, because of its textural features and also the presence of photo-active ion-radicals. On the other hand, the poor activity of c.TiO2 for water splitting is related to certain defect-induced inter-band charge trapping states in the close vicinity of valence and conduction bands of c.TiO2, as revealed by thermoluminescence spectroscopy. Further, the dispersion of nanosize gold particles gave rise to augmented activity of both the catalysts, particularly for water splitting. This is explained by the promotional role of Au-0 or Au-0/TiO2 interfacial sites in the adsorption and charge-adsorbate interaction processes. (C) 2011 Elsevier B.V. All rights reserved.

}, keywords = {Band-structure, Interfaces, Microstructure, Nanostructures, Semiconductors}, issn = {0254-0584}, doi = {10.1016/j.matchemphys.2011.01.029}, author = {Deshpande, Aparna and Madras, Giridhar and Gupta, N. M.} } @article { ISI:000303485400020, title = {Effects of grain morphology, microstructure and dispersed metal cocatalyst on the photoreduction of water over impurity-doped LaInO3}, journal = {Materials Research Bulletin}, volume = {47}, number = {5}, year = {2012}, month = {MAY}, pages = {1217-1228}, publisher = {PERGAMON-ELSEVIER SCIENCE LTD}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND}, abstract = {

The single phase lanthanum indates doped with Ga (for La) and N (for O), i.e. La1-xGaxInO3 (0 \<= x \<= 0.2) and LaInO1-yNy (y similar to 0.6), exhibit significant activity for photoreduction of water; the yield of H-2 produced depending on dopant, excitation source, and addition of a sacrificial reagent. The two-step H-2 evolution observed for this reaction corresponds with the two distinct absorbance regimes displayed by these materials, one in UV-region due to bandgap excitation and the other in visible region arising from the transitions involving sub-bandgap donor or acceptor energy states. The photocatalytic activity of these d(10) metal oxides increases on coating with a metal/metal oxide co-catalyst, gold exhibiting superior activity to Pt and NiO, irrespective of excitation source and sample composition. The preparation-controlled particle morphology, doping-induced lattice imperfections, and metal/semiconductor hetero-junctions are envisaged to play a key role in the absorption characteristics and photocatalytic water reduction activity of metal/LaInO3 nanocomposites. (C) 2012 Elsevier Ltd. All rights reserved.

}, keywords = {Catalytic properties, Chemical synthesis, Electron microscopy, Interfaces, Semiconductors}, issn = {0025-5408}, doi = {10.1016/j.materresbull.2012.01.031}, author = {Dhanasekaran, P. and Gupta, N. M.} } @article { ISI:000372156200013, title = {Synthesis of Sn-containing anatase (TiO2) by sol-gel method and their performance in catalytic water splitting under visible light as a function of tin content}, journal = {Materials Letters}, volume = {171}, year = {2016}, month = {MAY}, pages = {50-54}, publisher = {ELSEVIER SCIENCE BV}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

Sol-gel route was employed to prepare a series of Sn-containing anatase with different molar (Ti/Sn) ratios ranging from 49 to 1. Samples were characterized by powder XRD, UV-vis, XPS, SEM, EDAX, low temperature N-2 sorption technique and Raman Spectroscopy. Except anatase phase, no other crystalline phase was observed when Ti/Sn molar ratio was varied from 49 to 9 and for Sn free sample. However, further decrease in the ratio lead to the appearance of additional SnO2 phase whose peak intensities were increased with the increase in the tin content. Irrespective of tin content, all samples showed red-shift in UV-vis spectra. Moreover, samples showed Raman shift to higher vibration side from 143 cm(-1) to 147 cm(-1) indicating the doping of Sn2+ into TiO2. By virtue of low band gap, anatase crystallite size and an absence of XRD visible SnO2, ST (19) has shown maximum photocatalytic activity upon 1 wt\% Pt loading. It has exhibited the highest rate (0.1264 mmole/g/h) for visible light induced hydrogen evolution by water splitting. (C) 2016 Elsevier B.V. All rights reserved.

}, keywords = {Semiconductors, Sn2+ doped titania, SnO2/TiO2, Sol-gel preparation, visible light, water splitting}, issn = {0167-577X}, doi = {10.1016/j.matlet.2016.02.055}, author = {Tangale, N. P. and Niphadkar, P. S. and Samuel, V. and Deshpande, Suvarna S. and Joshi, P. N. and Awate, S. V.} }