X-ray-induced production of gold nanoparticles on a SiO2/Si system and in a poly(methyl methacrylate) matrix

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buir.contributor.authorSüzer, Şefik
dc.citation.epage442en_US
dc.citation.issueNumber1en_US
dc.citation.spage437en_US
dc.citation.volumeNumber21en_US
dc.contributor.authorKaradas, F.en_US
dc.contributor.authorErtas, G.en_US
dc.contributor.authorOzkaraoglu, E.en_US
dc.contributor.authorSüzer, Şefiken_US
dc.date.accessioned2016-02-08T10:24:30Z
dc.date.available2016-02-08T10:24:30Z
dc.date.issued2005en_US
dc.departmentDepartment of Chemistryen_US
dc.description.abstractProlonged exposure to X-rays of HAuCl4 deposited from an aqueous solution onto a SiO2/Si substrate or into a poly(methyl methacrylate) (PMMA) matrix induces reduction of the Au3+ ions to Au0 and subsequent nucleation to gold nanoclusters as recorded by X-ray photoelectron spectroscopy. The corresponding major oxidation product is determined as chlorine {HAuCl4(ads) + X-rays -Au(ads) + (3/2)Cl 2(ada) + HCl(ads)}, which is initially adsorbed onto the surface but eventually diffuses out of the system into the vacuum. The reduced gold atoms aggregate (three-dimensionally) into gold nanoclusters as evidenced by the variation in the binding energy during X-ray exposure, which starts as 1.3 eV but approaches a value that is 0.5 eV higher than that of the bulk gold. The disappearance of the oxidation product (Cl2p signal) and the growth of the nanoclusters (related to the measured binding energy difference between the Si2p of the oxide and Au4f of the reduced gold) exhibit first-order kinetics which is approximately 3 times slower than the reduction of Au3+, indicating that both of the former processes are diffusion controlled. Similarly, gold ions incorporated into PMMA can also be reduced and aggregated to gold nanoclusters using 254 nm deep UV irradiation in air evidenced by UV - vis - NIR absorption spectrocopy.en_US
dc.identifier.doi10.1021/la0478604en_US
dc.identifier.issn0743-7463
dc.identifier.urihttp://hdl.handle.net/11693/24127
dc.language.isoEnglishen_US
dc.publisherAmerican Chemical Societyen_US
dc.relation.isversionofhttp://dx.doi.org/10.1021/la0478604en_US
dc.source.titleLangmuiren_US
dc.subjectBinding energyen_US
dc.subjectIrradiationen_US
dc.subjectOxidationen_US
dc.subjectReaction kineticsen_US
dc.subjectSilicaen_US
dc.subjectSubstratesen_US
dc.subjectX ray photoelectron spectroscopyen_US
dc.subjectFirst - order kineticsen_US
dc.subjectFormer processesen_US
dc.subjectGold atomsen_US
dc.subjectGold nanoparticlesen_US
dc.subjectGold compoundsen_US
dc.subjectAdsorptionen_US
dc.subjectBindingen_US
dc.titleX-ray-induced production of gold nanoparticles on a SiO2/Si system and in a poly(methyl methacrylate) matrixen_US
dc.typeArticleen_US

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