Publicaciones 2011-2020

@article{RN365,
title = {Polymer-Based Nanocomposites: In Situ Generation and Immobilization of Gold Nanoparticles on Poly(N-Vinyl-2-Pyrrolidone) and Poly(Epsilon-Caprolactone) Thin Films},
author = { M. Mendez-Lopez and C. Saldias and M. Urz\'{u}a and V. Villalobos and M. Schmidt and D. Radic and A. Leiva},
url = {/brokenurl#<Go to ISI>://WOS:000417111000053},
doi = {10.1166/jnn.2017.13868},
issn = {1533-4880},
year = {2017},
date = {2017-01-01},
journal = {Journal of Nanoscience and Nanotechnology},
volume = {17},
number = {12},
pages = {9074-9080},
abstract = {In this work, we report an interesting method for simultaneous obtaining and immobilization of gold nanoparticles onto polymer thin films. Polymer-based nanocomposites were generated by spontaneous adsorption and reduction of Au III ions onto polymeric films surfaces. Poly(N-vinyl-2-pyrrolidone) and poly(epsilon-caprolactone), polymers that have shown their capability to reduce Au III and stabilize the generated gold nanoparticles, were used. The polymer film thickness and hydrophilic or hydrophobic nature of the solid substrate on which the polymers are deposited, directly affect the quantity and characteristics of the gold nanoparticles incorporated in films. Therefore, these parameters can be used to obtain nanocomposites with modulated features. The method presented is a simple route to produce nanocomposites with a high potential for use in diverse technological applications.},
keywords = {chemistry, copolymers, films, gold growth metal nanocomposites, nanoparticles, polymer reducing silver stabilization, step synthesis, thin},
pubstate = {published},
tppubtype = {article}
}

@article{RN302,
title = {Molybdenum Trioxide Thin Films Doped with Gold Nanoparticles Grown by a Sequential Methodology: Photochemical Metal-Organic Deposition (Pmod) and Dc-Magnetron Sputtering},
author = { C. Castillo and G. Buono-Core and C. Manzur and N. Yutronic and R. Sierpe and G. Cabello and B. Chornik},
url = {/brokenurl#<Go to ISI>://WOS:000378145500014},
doi = {10.4067/S0717-97072016000100014},
issn = {0717-9707},
year = {2016},
date = {2016-01-01},
journal = {Journal of the Chilean Chemical Society},
volume = {61},
number = {1},
pages = {2816-2820},
abstract = {Gold nanoparticles (AuNPs) were deposited by DC-magnetron sputtering onto molybdenum trioxide (MoO3) thin films grown by Photochemical Metal-Organic Deposition (PMOD) on Si(100) and borosilicate glass substrates. The chemical, optical and morphology properties of the films were studied by UV/Vis Spectroscopy, Scanning Electron Microscopy (SEM), X-Ray Photoelectron Spectroscopy (XPS), and X-Ray Diffraction (XRD). SEM revealed that AuNPs formed after 5 s of sputtering. AuNPs are spherical and have both an average diameter of 18 nm and a relatively narrow size distribution. As the deposition time increases, larger structures are formed by an aggregation of AuNPs. XPS studies of the AuNP/MoO3 films on Si(100) showed the presence of Mo(VI) and Mo(V), which indicated that the films were primarily non-stoichiometric molybdenum oxides. The occurrence of oxygen vacancies in the substrate play an important role to stabilize the AuNPs.},
keywords = {catalysis, diffraction, films, moo3, nanostructures, optical-properties, oxidation, oxide-films, oxides, photoelectron resonance, selective size, spectroscopy, sputtering, support, surface-plasmon temperature, thin x-ray xps},
pubstate = {published},
tppubtype = {article}
}

@article{RN267,
title = {Shell-Isolated Nanoparticle-Enhanced Fluorescence (Shinef) of Cdte Quantum Dots},
author = { M. Ramirez-Maureira and C.V. Vargas and A. Riveros and P.J.G. Goulet and I.O. Osorio-Roman},
url = {/brokenurl#<Go to ISI>://WOS:000348263600048},
doi = {10.1016/j.matchemphys.2014.12.003},
issn = {0254-0584},
year = {2015},
date = {2015-01-01},
journal = {Materials Chemistry and Physics},
volume = {151},
pages = {351-356},
publisher = {2014 Elsevier B.V.},
abstract = {We report shell-isolated nanoparticle-enhanced fluorescence (SHINEF) of CdTe quantum dots. Enhanced spectra are obtained after Ag SHINs were spread onto homogenous CdTe quantum dot/polyelectrolyte layer-by-layer (LbL) films on quartz. The thin silica shell of the SHINs effectively isolates the Ag cores, preventing short-range quenching to the metal and enabling plasmon enhancement of the quantum dot fluorescence (ca. 35 fold).},
keywords = {cdse chemical coatings, films, nanostructures, semiconductors, spectrum, surface, synthesis, thin},
pubstate = {published},
tppubtype = {article}
}

@article{RN151,
title = {Thin Films of Amphiphilic Polyelectrolytes. Soft Materials Characterized by Kelvin Probe Force Microscopy},
author = { X. Briones and M. Urz\'{u}a and H. Rios and F.J. Espinoza-Beltran and R. Dabirian and M. Yazdani-Pedram},
url = {/brokenurl#<Go to ISI>://WOS:000326204200035},
doi = {10.1016/j.polymer.2013.07.066},
issn = {0032-3861},
year = {2013},
date = {2013-01-01},
journal = {Polymer},
volume = {54},
number = {21},
pages = {5733-5740},
publisher = {2013 Elsevier Ltd.},
abstract = {Hydrophobically modified amphiphilic polyelectrolyte films derived from poly (maleic anhydride-altstyrene) containing hydrophobic aryl-alkyl type side chains such as phenyl-ethyl, phenyl-butyl, naphthyl-ethyl and naphthyl-butyl were studied by Kelvin probe force microscopy. These films were adsorbed from polyelectrolyte solutions at 0.001 mol/L and 0.1 mol/L NaCl onto silicon wafers modified with 3-aminopropyltrimethoxysilane. At high ionic strength, the work function was dependent on the hydrophobic character of the side chain. At low ionic strength this behavior was determined by the spacer group in the side chain. The fractal analysis of the films indicated self-affinity surfaces whereas the fractal dimensions of the surface topography follow a similar trend as the electronic work function with the ionic strength. This behavior can be explained by the increasing hydrophobic character of the side chain with naphthyl moieties. Relationship between the molecular structure and the fractal dimensions with the work function of the adsorbed polyelectrolytes was found.},
keywords = {architectures, dimensions, films, force fractal function, kelvin microscopy, monolayers polyelectrolyte probe work},
pubstate = {published},
tppubtype = {article}
}

@article{RN92,
title = {Structural Aspects of Polyanion and Hydrophobically Modified Polycation Multilayers on Hydrophilic or Hydrophobic Surfaces},
author = { J. Amim and F.C.B. Maia and P.B. Miranda and M. Urz\'{u}a and D.F.S. Petri},
url = {/brokenurl#<Go to ISI>://WOS:000304665400008},
doi = {10.1039/c2sm25658d},
issn = {1744-683x},
year = {2012},
date = {2012-01-01},
journal = {Soft Matter},
volume = {8},
number = {24},
pages = {6462-6470},
abstract = {Multilayer films of carboxymethylcellulose (CMC), a polyanion, and bromide salts of poly(4-vinylpyridine) quaternized with linear aliphatic chains of 2 (ethyl) and 5 (pentyl) carbon atoms, coded as QPVP-C2 and QPVP-C5, respectively, were fabricated by layer-by-layer (LbL) self-assembly onto Si/SiO2 wafers (hydrophilic substrate) or polystyrene, PS, films (hydrophobic substrate). The films were characterized by means of ex situ and in situ ellipsometry, atomic force microscopy (AFM), contact angle measurements and sum frequency generation vibrational spectroscopy (SFG). Antimicrobial tests were used to assess the exposure of pyridinium moieties to the aqueous medium. In situ ellipsometry indicated that for Si/SiO2 the chains were more expanded than the PS films and both substrates systems composed of QPVP-C5 were thicker than those with QPVP-C2. For dried layers, the alkyl side group size had a small effect on the thickness evolution, regardless of the substrate. At pH 2 the multilayers showed high resistance, evidencing that the build-up is driven not only by cooperative polymer-polymer ion pairing, but also by hydrophobic interactions between the alkyl side chains. The LbL films became irregular as the number of depositions increased. After the last deposition, the wettability of QPVP-C2 or QPVP-C5 terminated systems on the Si/SiO2 wafers and PS films were similar, except for QPVP-C2 on Si/SiO2 wafers. Unlike the morphology observed for LbL films on Si/SiO2 wafers, PS induced the formation of porous structures. SFG showed that in air the molecular orientation of pyridinium groups in multilayers with QPVP-C5 was stronger than in those containing QPVP-C2. The exposure of pyridinium moieties to the aqueous medium was more pronounced when the LbL were assembled on Si/SiO2 wafers.},
keywords = {behavior, buildup, by-layer deposition, films, multilayers, polyelectrolyte surfaces, terminated virus},
pubstate = {published},
tppubtype = {article}
}

@article{RN28i,
title = {Influence of the Nature of the Absorption Band on the Potential Performance of High Molar Extinction Coefficient Ruthenium(Ii) Polypyridinic Complexes as Dyes for Sensitized Solar Cells},
author = { F. Gajardo and M. Barrera and R. Vargas and I. Crivelli and B. Loeb},
url = {/brokenurl#<Go to ISI>://WOS:000292010000012},
doi = {10.1021/ic1020862},
issn = {0020-1669},
year = {2011},
date = {2011-01-01},
journal = {Inorganic Chemistry},
volume = {50},
number = {13},
pages = {5910-5924},
abstract = {When tested in solar cells, ruthenium polypyridinic dyes with extended pi systems show an enhanced light-harvesting capacity that is not necessarily reflected by a high (collected electrons)/(absorbed photons) ratio. Provided that metal-to-ligand charge transfer bands, MLCT, are more effective, due to their directionality, than intraligand (IL) pi-pi* bands for the electron injection process in the solar cell, it seems important to explore and clarify the nature of the absorption bands present in these types of dyes. This article aims to elucidate if all the absorbed photons of these dyes are potentially useful in the generation of electric current. In other words, their potentiality as dyes must also be analyzed from the point of view of their contribution to the generation of excited states potentially useful for direct injection. Focusing on the assignment of the absorption bands and the nature of the emitting state, a systematic study for a series of ruthenium complexes with 4,4'-distyryl-2,2'-dipyridine (LH) and 4,4'-bis[p-(dimethylamino)-alpha-styryl]-2,2'-bipyridine (LNMe2) "chromophoric" ligands was undertaken. The observed experimental results were complemented with TDDFT calculations to elucidate the nature of the absorption bands, and a theoretical model was proposed to predict the available energy that could be injected from a singlet or a triplet excited state. For the series studied, the results indicate that the percentage of MLCT character to the anchored ligand for the lower energy absorption band follows the order [Ru(deebpy)(2)(LNMe2)](PF6)(2) > [Ru(deebpy)(2)(LH)] (PF6)(2) > [Ru(deebpy)(LH)(2)](PF6)(2), where deebpy is 4,4'-bis(ethoxycarbonyl)-2,2'-bipyridine, predicting that, at least from this point of view, their efficiency as dyes should follow the same trend.},
keywords = {charge-transfer conversion, correlation-energy, density, excited-states, films, light, nanocrystalline optical-properties, sensitizers, tio2},
pubstate = {published},
tppubtype = {article}
}