Photochemistry on Metal Nanoparticles

Watanabe, Kenji; Menzel, D.; Nilius, Niklas; Freund, Hans‐Joachim

doi:10.1021/cr050167g

Cited by 457 publications

(319 citation statements)

References 210 publications

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“…Recently, nanoparticles have attracted considerable attention as a key material in nanomaterial science and technology [1][2][3][4][5][6]. Their application is particularly important in biological fields such as bioseparation [7,8], diagnostics [9,10], bioimaging [11,12] and therapy [13][14][15].…”

Section: Introductionmentioning

confidence: 99%

Engineering of poly(ethylene glycol) chain-tethered surfaces to obtain high-performance bionanoparticles

Nagasaki

2010

Science and Technology of Advanced Materials

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A poly(ethylene glycol)-b-poly [2-(N,N-dimethylamino)ethyl methacrylate] block copolymer possessing a reactive acetal group at the end of the poly(ethylene glycol) (PEG) chain, that is, acetal-PEG-b-PAMA, was synthesized by a proprietary polymerization technique. Gold nanoparticles (GNPs) were prepared using the thus-synthesized acetal-PEG-b-PAMA block copolymer. The PEG-b-PAMA not only acted as a reducing agent of aurate ions but also attached to the nanoparticle surface. The GNPs obtained had controlled sizes and narrow size distributions. They also showed high dispersion stability owing to the presence of PEG tethering chains on the surface. The same strategy should also be applicable to the fabrication of semiconductor quantum dots and inorganic porous nanoparticles. The preparation of nanoparticles in situ, i.e. in the presence of acetal-PEG-b-PAMA, gave the most densely packed polymer layer on the nanoparticle surface; this was not observed when coating preformed nanoparticles. PEG/polyamine block copolymer was more functional on the metal surface than PEG/polyamine graft copolymer, as confirmed by angle-dependent x-ray photoelectron spectroscopy. We successfully solubilized the C 60 fullerene into aqueous media using acetal-PEG-b-PAMA. A C 60 /acetal-PEG-b-PAMA complex with a size below 5 nm was obtained by dialysis. The preparation and characterization of these materials are described in this review.

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Section: Introductionmentioning

confidence: 99%

Engineering of poly(ethylene glycol) chain-tethered surfaces to obtain high-performance bionanoparticles

Nagasaki

2010

Science and Technology of Advanced Materials

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“…Hereby, possible energy-exchange mechanisms between particle plasmons and single-electron excitations in molecules and the oxide support need to be explored, as they form the basis for processes occurring in photo-catalytically active or dye-sensitized oxide systems. 15,139 As demonstrated in the previous paragraphs, the STM is a powerful tool to investigate the structural, electronic, vibrational and optical properties of oxide materials at the nanometer scale. A large number of examples that will demonstrate this potential will be given in the following chapters.…”

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confidence: 99%

Properties of oxide thin films and their adsorption behavior studied by scanning tunneling microscopy and conductance spectroscopy

Nilius

2009

Surface Science Reports

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The preparation of thin oxide films on metal supports is a versatile approach to explore the properties of oxide materials that are otherwise inaccessible to most surface science techniques due to their insulating nature. Although substantial progress has been made in the characterization of oxide surfaces with spatially averaging techniques, a local view is often essential to provide comprehensive understanding of such systems. The scanning tunneling microscope (STM) is a powerful tool to obtain atomic-scale information on the growth behavior of oxide films, the resulting surface morphology and defect structure.

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“…In this work, Au plasmonic nanopyramid (NPY) structures, prepared via self-assembled nanosphere lithography, are introduced into a narrow bandgap organic solar cell to examine the effect of tunable plasmonic resonance and surface passivation on light absorption and exciton dissociation. With this setup, the plasmonic near-field created by the Au NPYs under illumination acts as the antenna to influence the resonant optical absorption of the nearby photoactive layer, consisting of a silole-thiophene conjugated polymer (P3) and [6,6]-phenyl-C61-butyric acid methyl ester (PCBM). We specifically selected P3 as the photoactive polymer.…”

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Surface-passivated plasmonic nano-pyramids for bulk heterojunction solar cell photocurrent enhancement

et al. 2012

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We report that self-assembled gold (Au) nanopyramid arrays can greatly enhance the photocurrent of narrow bandgap organic solar cells using their plasmonic near-field effect. The plasmonic enhanced power conversion efficiency exhibited up to 200% increase under the AM 1.5 solar illumination.Organic thin film photovoltaic devices have attracted enormous attention in recent years due to their low-cost, easy processing, lightweight and flexible properties. 1,2 For an ideal solar cell to have high power conversion efficiency, adequate light absorption in the photoactive layer is required. To achieve this, increasing the thickness of the photoactive layer is an effective method. However, the increased photoactive layer thickness causes a decrease in the inner electric field, which slows down charge drift and increases the possibility of recombination, and hence reduces charge carrier collection. 3 Designing an efficient solar cell with high light absorption at a relatively small film thickness is a challenge to be resolved.Previously, it was found that the absorption and emission properties of photoactive materials can be effectively influenced by the nearby resonant plasmon from metal nanostructures which enhance not only Raman scattering, 4 fluorescence, 5 and photochemistry, 6 but also photovoltaic response. 7 The plasmonic near-field enhancement or improved coupling to guided modes in metal nanostructures will induce resonant absorption in neighboring organic photoactive materials and thus increase the concentration of excitons. 8 It was shown by theoretical investigation that optical absorption in thin film organic solar cells was greatly enhanced by up to 50% under the plasmonic effect of metallic gratings. 4 Kulkarni et al. 4 showed that charge carrier generation could be enhanced more than 3 times if a thin film of silver nanoprisms was introduced under the organic photovoltaic materials, which could in principle be used to increase photocurrent in organic thin film solar cells. By blending Au nanoparticles with poly(3,4-ethylenedioxythiophene)-poly-(styrenesulfonate) (PEDOT:PSS), Yang et al. 10 showed that plasmonic optical absorption can be used to enhance the photovoltaic performance of tandem structured organic solar cells. However, early studies have not shown the improved energy conversion efficiency in organic solar cells when plasmonic metal nanostructures were embedded into the photoactive layer, although plasmon resonant enhanced optical absorption existed; this is due to the reduced hole mobility caused by disturbed ordering in the polymer phase, or the quenching of excited states in the photoactive polymers. 11 Compared with spherical nanoparticles, triangular shaped nanoparticles show a strong plasmonic resonance at the tips, from both theory 12 and experiments. 9 The plasmonic resonance peak of triangular shaped metal NPs can also be tuned across the entire visible region and even into the near-infrared (NIR), which cannot be easily done with spherical particles. 13 The well-defined and tunable ...

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Photochemistry on Metal Nanoparticles

Cited by 457 publications

References 210 publications

Engineering of poly(ethylene glycol) chain-tethered surfaces to obtain high-performance bionanoparticles

Engineering of poly(ethylene glycol) chain-tethered surfaces to obtain high-performance bionanoparticles

Properties of oxide thin films and their adsorption behavior studied by scanning tunneling microscopy and conductance spectroscopy

Surface-passivated plasmonic nano-pyramids for bulk heterojunction solar cell photocurrent enhancement

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