01616nas a2200193 4500008004100000022001400041245007500055210006900130260007100199300001400270490000700284520091900291100002001210700002001230700001501250700002001265700003001285856010701315 2005 eng d a0743-746300aGold nanoparticle networks with photoresponsive interparticle spacings0 aGold nanoparticle networks with photoresponsive interparticle sp a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcAUG a7979-79840 v213 a

Photoresponsive gold nanoparticle networks were prepared by functionalizing them with azobenzene derivatives. A network can be formed when a linker molecule constituting the azobenzene moiety suitably derivatized on either side with gold surface sensitive groups such as thiols and amines is added to the nanoparticle solution. It is shown that the interparticle spacing in the networks could be controlled by the reversible trans-cis isomerization of the azobenzene moiety induced by UV and visible light, respectively. The photoinduced variation in the interparticle spacings is inferred by the changes in the optical spectra of the gold nanoparticles which display a red or blue shift in the surface plasmon resonance peak depending on a decrease or increase in the interparticle spacing, respectively. Transmission electron microscopy images are in consonance with the evidence from the optical spectra.

1 aSidhaye, D., S.1 aKashyap, Sudhir1 aSastry, M.1 aHotha, Srinivas1 aPrasad, Bhagavatula L. V. uhttps://library.ncl.res.in/content/gold-nanoparticle-networks-photoresponsive-interparticle-spacings-001230nas a2200169 4500008004100000022001400041245003600055210003600091260011000127300001400237490000700251520065200258100003000910700002100940700002600961856007300987 2008 eng d a0306-001200aGold nanoparticle superlattices0 aGold nanoparticle superlattices aTHOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLANDbROYAL SOC CHEMISTRYcSEP a1871-18830 v373 a

Ordered metal nanoparticle assemblies-superlattices-have captivated and stirred the imagination of scientists and engineers alike and promise great prospect for future technologies. This potential though will greatly be determined by the understanding and control that can be exerted on the assembling processes. This tutorial review presents a brief account of the factors that govern the formation of superlattices and then presents several examples of gold nanoparticle superlattices that are distinguished by the size of participating particles, chain length/functional group of the capping agent, the substrates on which they form etc.

1 aPrasad, Bhagavatula L. V.1 aSorensen, C., M.1 aKlabunde, Kenneth, J. uhttps://library.ncl.res.in/content/gold-nanoparticle-superlattices-001545nas a2200193 4500008004100000022001400041245011300055210006900168260011000237300001200347490000600359520075400365100001801119700002301137700001501160700001801175700003001193856012801223 2012 eng d a2040-336400aGellan gum capped silver nanoparticle dispersions and hydrogels: cytotoxicity and in vitro diffusion studies0 aGellan gum capped silver nanoparticle dispersions and hydrogels  aTHOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLANDbROYAL SOC CHEMISTRYcOCT a563-5670 v43 a

The preparation of highly stable water dispersions of silver nanoparticles using the naturally available gellan gum as a reducing and capping agent is reported. Further, exploiting the gel formation characteristic of gellan gum silver nanoparticle incorporated gels have also been prepared. The optical properties, morphology, zeta potential and long-term stability of the synthesized silver nanoparticles were investigated. The superior stability of the gellan gum-silver nanoparticle dispersions against pH variation and electrolyte addition is revealed. Finally, we studied the cytotoxicity of AgNP dispersions in mouse embryonic fibroblast cells (NIH3T3) and also evaluated the in vitro diffusion of AgNP dispersions/gels across rat skin.

1 aDhar, Sheetal1 aMurawala, Priyanka1 aShiras, A.1 aPokharkar, V.1 aPrasad, Bhagavatula L. V. uhttps://library.ncl.res.in/content/gellan-gum-capped-silver-nanoparticle-dispersions-and-hydrogels-cytotoxicity-and-vitro-001955nas a2200241 4500008004100000022001400041245019800055210006900253260007300322300001200395490000800407520098500415653001401400653001401414653001901428653001801447653002201465100002001487700001901507700002501526700003001551856013201581 2012 eng d a0927-775700aGold nanoparticle embedded hydrogel matrices as catalysts: better dispersibility of nanoparticles in the gel matrix upon addition of N-bromosuccinimide leading to increased catalytic efficiency0 aGold nanoparticle embedded hydrogel matrices as catalysts better aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcNOV a296-3010 v4143 a

A simple and convenient method for generating and immobilizing gold NPs into polyethylene glycol-polyurethane (PEGPU) matrices is presented. The gold NP immobilized PEGPU (Au NP-PEGPU) hydrogel matrices are easy to handle and can be used as catalysts. The efficiency, reusability and durability of the Au NP-PEGPU catalyst matrices were investigated using the reduction of 4-nitroaniline (4NA) to p-phenylenediamine (p-PDA) by sodium borohydride in the presence of the catalyst as a test reaction. The Au NPs in the PEGPU matrix got aggregated after 3 cycles of catalysis but dispersion could be regenerated by the addition of N-bromosuccinimide (NBS). After this regeneration process the Au NPs-PEGPU matrix showed excellent efficiency without any aggregation, leaching or degradation. The reusability of the catalyst for 28 cycles yielding a total turnover number of 3220 and turn over frequency of 0.152 s(-1) is demonstrated. (C) 2012 Elsevier B.V. All rights reserved.

10acatalysis10ahydrogels10aImmobilization10aNanoparticles10aTurn over numbers1 aRamtenki, Vilas1 aAnumon, V., D.1 aBadiger, Manohar, V.1 aPrasad, Bhagavatula L. V. uhttps://library.ncl.res.in/content/gold-nanoparticle-embedded-hydrogel-matrices-catalysts-better-dispersibility-nanoparticles-002129nas a2200181 4500008004100000245012800041210006900169260000800238300001400246490000700260520143600267100001801703700002201721700002701743700001901770700003001789856012801819 2018 eng d00aGeneric and scalable method for the preparation of monodispersed metal sulfide nanocrystals with tunable optical properties0 aGeneric and scalable method for the preparation of monodispersed cMAY a5788-57970 v343 a

A rational synthetic method that produces monodisperse and air-stable metal sulfide colloidal quantum dots (CQDs) in organic nonpolar solvents using octyl dithiocarbamic acid (C(8)DTCA) as a sulfur source, is reported. The fast decomposition of metal-C(8)DTCA complexes in presence of primary amines is exploited to achieve this purpose. This novel technique is generic and can be applied to prepare diverse CQDs, like CdS, MnS, ZnS, SnS, and In2S3, including more useful and in-demand PbS CQDs and plasmonic nanocrystals of Cu2S. Based on several control reactions, it is postulated that the reaction involves the in situ formation of a metal-C(8)DTCA complex, which then reacts in situ with oleylamine at slightly elevated temperature to decompose into metal sulfide CQDs at a controlled rate, leading to the formation of the materials with good optical characteristics. Controlled sulfur precursor's reactivity and stoichiometric reaction between C(8)DTCA and metal salts affords high conversion yield and large-scale production of monodisperse CQDs. Tunable and desired crystal size could be achieved by controlling the precursor reactivity by changing the reaction temperature and reagent ratios. Finally, the photovoltaic devices fabricated from PbS CQDs displayed a power conversion efficiency of 4.64% that is comparable with the reported values of devices prepared with PbS CQDs synthesized by the standard methods.

1 aBera, Abhijit1 aMandal, Debranjan1 aGoswami, Prasenjit, N.1 aRath, Arup, K.1 aPrasad, Bhagavatula L. V. uhttps://library.ncl.res.in/content/generic-and-scalable-method-preparation-monodispersed-metal-sulfide-nanocrystals-tunable