@article { ISI:000227393300019, title = {Phase transfer of oleic acid capped NicoreAgshell nanoparticles assisted by the flexibility of oleic acid on the surface of silver}, journal = {Journal of Colloid and Interface Science}, volume = {283}, number = {2}, year = {2005}, month = {MAR}, pages = {422-431}, publisher = {ACADEMIC PRESS INC ELSEVIER SCIENCE}, type = {Article}, address = {525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA}, abstract = {

The phase transfer protocols in vogue for the oleic acid capped silver nanoparticles, viz., salt-induced precipitation and redispersion or phosphoric acid-induced method, are examined and compared thoroughly. A comprehensive evaluation with respect to the mechanistic aspects involved is made and the merits and demerits of the different procedures are delineated. It is found that the salt-induced precipitation and redispersion is more versatile in that the precipitate can actually be redispersed in both aqueous and organic media. However, in terms of mechanism both the routes seem to be very similar wherein the orientational change of oleic acid on the silver surface in the two different environments-organic and aqueous-plays a crucial role in the adaptability of the system to the different environments. Subsequently, this change of orientation of oleic acid on silver surface in aqueous and organic media has been utilized to phase transfer Ni-based nanoparticulate systems. The nascent oleic acid-capped Ni nanoparticles, which were synthesized by a foam-based protocol, were dispersible in water but not in nonpolar organic media such as cyclohexane or toluene. Then, just by coating a thin shell of silver on them we could achieve complete phase transfer of the NicoreAgshell from aqueous to organic media following similar procedures used for oleic acid-capped silver nanoparticles. Here, the phase transfer seems to be facilitated by the orientational flexibility of oleic acid on the silver surface as opposed to other metal surfaces as evidenced from the infrared and thermogravimetric analyses of oleic acid-capped Ni and NicoreAgshell nanoparticles. This orientation-assisted phase transfer method could be generalized and can be adapted to other systems where, if the nascent nanoparticles cannot be phase transferred as is, they can be coated by a silver shell and oleic acid making them suitable for dispersion in both aqueous and organic media. (C) 2004 Elsevier Inc. All rights reserved.

}, keywords = {(1) HNMR, FTIR, Phase transfer, transmetalation core-shell nanoparticles, UV-Vis}, issn = {0021-9797}, doi = {10.1016/j.jcis.2004.09.018}, author = {Bala, Tanushree and Swami, A. and Bhagavatula L. V. Prasad and Sastry, M.} } @article { ISI:000263733200011, title = {Preparation of nearly monodisperse nickel nanoparticles by a facile solution based methodology and their ordered assemblies}, journal = {Journal of Physical Chemistry C}, volume = {113}, number = {9}, year = {2009}, month = {MAR}, pages = {3426-3429}, publisher = {AMER CHEMICAL SOC}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {

Nickel nanoparticles have been synthesized by a simple wet chemical reduction technique in the presence of a surfactant sodium dodecyl sulfate (SDS) and a capping agent oleic acid. Varying the concentration of the surfactant and the capping agent has been found to critically govern the nature of the nanoparticles prepared. It is observed that at an optimum concentration of SDS and oleic acid, nearly monodisperse Ni nanoparticles are obtained that form highly ordered hexagonally close-packed structures on electron microscopy grids by a simple drop coating procedure. It is also shown that the presence of oleic acid is necessary for the stability of the Ni nanoparticles synthesized. Structural and magnetic characterizations of the nanoparticles are also presented.

}, issn = {1932-7447}, doi = {10.1021/jp807542w}, author = {Sidhaye, Deepti S. and Bala, Tanushree and Srinath, S. and Srikanth, H. and Poddar, Pankaj and Sastry, Murali and Bhagavatula L. V. Prasad} } @article { ISI:000341226500016, title = {pH-Dependent single-step rapid synthesis of cuo and cu2o nanoparticles from the same precursor}, journal = {Crystal Growth \& Design}, volume = {14}, number = {9}, year = {2014}, month = {SEP}, pages = {4329-4334}, publisher = {AMER CHEMICAL SOC}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {

A single-step protocol to prepare Cu2O and CuO nanocrystalline particles from the same precursor by microwave irradiation has been developed using the pH of the solution as the only variable parameter. The utility of different bivalent Cu-precursors for synthesis of CuO and Cu2O nanoparticles was also investigated. The morphology, phase purity, and optical properties of these nanoparticles were analyzed using TEM, SEM, XRD, and optical spectroscopy. The band edges were determined using cyclic voltammetry. Field effect transistors based on CuO nanoparticles showed a hole mobility of 3.5 x 10(-2) cm(2) V-1 s(-1), making them a suitable candidate for energy-related applications. The effect of hydrazine vapor exposure on the IV-characteristics of CuO nanoparticles was also investigated. This revealed a decrease in source current with respect to time.

}, issn = {1528-7483}, doi = {10.1021/cg500394p}, author = {Nikam, Arun V. and Arulkashmir, Arulraj and Krishnamoorthy, Kothandam and Kulkarni, Amol A. and Bhagavatula L. V. Prasad} } @article { ISI:000354028700005, title = {Preparation of Ag(Shell)-Au(Core) nanoparticles by anti-galvanic reactions: are capping agents the {\textquoteleft}{\textquoteleft}real heroes{\textquoteright}{\textquoteright} of reduction?}, journal = {Colloids and Surfaces A-Physicochemical and Engineering Aspects}, volume = {478}, year = {2015}, month = {AUG}, pages = {30-35}, publisher = {ELSEVIER SCIENCE BV}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

The formation of Ag(shell)-Au(core) nanoparticles by the reduction of Ag+ ions on preformed Au NPs, mediated by the capping agents like dodecylamine is described. We clearly established that while monodisperse Ag(shell)-Au(core) structures can be formed in presence of weak surface binding ligands such as amines, strong binding ligands such as thiols, lead to formation of separate monometallic Au and Ag particles. Apart from highlighting the influence of metal-ligand binding strength on the formation of core-shell nanoparticle architectures, our study also provides an easy means to produce Ag( shell)-Au( core) structures. (C) 2015 Elsevier B.V. All rights reserved.

}, keywords = {Ag(shell)-Au(core) nanoparticles, Anti-Galvanic reactions}, issn = {0927-7757}, doi = {10.1016/j.colsurfa.2015.03.028}, author = {Sahu, Puspanjali and Bhagavatula L. V. Prasad} } @article {42673, title = {Preparation of Ni3S2 and Ni3S2-Ni nanosheets via solution based processes}, journal = {Crystal Growth \& Design}, volume = {15}, year = {2015}, month = {MAY}, pages = {2584{\textendash}2588}, abstract = {

An easy and convenient preparation of nanometer-thick sheets of Ni3S2 and Ni3S2{\textendash}Ni from solution processed molecularly thin sheets of Ni-thiolates is described. Both the Ni3S2 and Ni3S2{\textendash}Ni possessed sheet-like morphologies and displayed room temperature ferromagnetic characteristics. The ferromagnetic nature of these samples was also confirmed by MFM studies, and AFM/TEM investigations substantiated the sheet-like morphology of the samples.

}, doi = {10.1021/acs.cgd.5b00307}, author = {Busupalli, Balanagulu and Date, Kalyani S. and Datar, Suwarna and Bhagavatula L. V. Prasad} }