Publicaciones 2011-2020

@article{orellana2017palmitic,
title = {Palmitic Acid and Hexadecylamine Molecules Assdsorbed on Titania Surface in Hybrid Composites. Effect of Surfactants Using Density Functional Theory},
author = { C. Orellana and F. Mendizabal and G. Gonz\'{a}lez and S. Miranda-Rojas and L. Barrientos-Poblete},
url = {/brokenurl#<Go to ISI>://WOS:000401679900007},
doi = {10.1016/j.comptc.2017.04.006},
issn = {2210-271x},
year = {2017},
date = {2017-01-01},
journal = {Computational and Theoretical Chemistry},
volume = {1110},
pages = {50-59},
publisher = {2017 Elsevier B.V.},
abstract = {A complete theoretical characterization of the factors involved in the stabilization of hybrid laminar composites is reported, with the purpose of understanding the main interactions involved in the formation of these types of systems. The models were built using two different surfactants: hexadecylamine (HDA) and palmitic acid (PAc), on a cluster of titania (TiO2) which represents its anatase crystalline phase. We explored the relevance of the titania-surfactant and surfactant-surfactant interactions, and of the protonation state of the palmitic acid in the stabilization of the hybrid laminar composites. The results were rationalized using energy decomposition analysis (EDA) and the non-covalent interaction index (NIC). The interaction energies between HDA and the TiO2 surface without the contribution of the dispersion forces were -25 kcal/mol and -29 kcal/mol for the (1 0 0) and (1 01) surfaces, respectively. These results suggest the formation of a donor-acceptor bond between HDA-TiO2 allowing its stabilization. On the other hand, the interaction energy between PAc and the TiO2 (1 0 1) surface was about -45 kcal/mol without the dispersion term. Thus, the PAc-TiO2 model has a higher covalent character than the HDA-TiO2 interaction, as confirmed by the energy decomposition analyses. The results suggest new hybrid laminar composites which are better when carboxylic acid was used instead of amines. Therefore, the use of surfactants with the carboxyl functional group yielded more stable TiO2 hybrid composites. The interaction energy between surfactant chains was about -13 kcal/mol, confirming the importance of dispersion forces in the stabilization of these types of systems. The study of systems with palmitic acid was complemented by building some anionic models to show the importance of acid protons in those systems. However, when the acidic hydrogens were removed, the interaction energy between the PAc molecules considering the dispersion correction increased to 45 kcal/mol, with a highly repulsive character. These results suggest that the acid hydrogens of the PAc surfactants play a fundamental role in terms of correctly representing the carboxylic acid-TiO2 interface and the stabilization of the laminar hybrid composites.},
keywords = {basis-sets, bsse, calculations, catalysis, clusters, compounds, dft dft, dioxide dispersion enzymatic hexadecylamine, hydrogen-bonds, interactions, laminar n-body noncovalent palmitic photocatalysis properties, sensitized solar-cells, spectroscopic strong term, tio2, titanium},
pubstate = {published},
tppubtype = {article}
}

@article{RN307,
title = {Improvement of Photovoltaic Performance by Substituent Effect of Donor and Acceptor Structure of Tpa-Based Dye-Sensitized Solar Cells},
author = { N. Inostroza and F. Mendizabal and R. Arratia-P\'{e}rez and C. Orellana and C. Linares-Flores},
url = {/brokenurl#<Go to ISI>://WOS:000369312100025},
doi = {10.1007/s00894-015-2893-9},
issn = {1610-2940},
year = {2016},
date = {2016-01-01},
journal = {Journal of Molecular Modeling},
volume = {22},
number = {1},
abstract = {We report a computational study of a series of organic dyes built with triphenylamine (TPA) as an electron donor group. We designed a set of six dyes called (TPA-n, where n=0-5). In order to enhance the electron-injection process, the electron-donor effect of some specific substituent was studied. Thus, we gave insights into the rational design of organic TPA-based chromophores for use in dye-sensitized solar cells (DSSCs). In addition, we report the HOMO, LUMO, the calculated excited state oxidized potential E-dye*(eV) and the free energy change for electron-injection Delta G(inject)(eV), and the UV-visible absorption bands for TPA-n dyes by a time-dependent density functional theory (TDDFT) procedure at the B3LYP and CAM-B3LYP levels with solvent effect. The results demonstrate that the introduction of the electron-acceptor groups produces an intramolecular charge transfer showing a shift of the absorption wavelengths of TPA-n under studies.},
keywords = {approximation, cells, density design, dye-sensitized electron-transfer, electronic energy-levels, free functional molecular organic organic-dyes, porphyrins, semiconductor, solar spectra, surface theory, tio2},
pubstate = {published},
tppubtype = {article}
}

@article{RN251,
title = {Substituents Role in Zinc Phthalocyanine Derivatives Used as Dye-Sensitized Solar Cells. A Theoretical Study Using Density Functional Theory},
author = { C. Linares-Flores and F. Mendizabal and R. Arratia-Perez and N. Inostroza and C. Orellana},
url = {/brokenurl#<Go to ISI>://WOS:000365814400033},
doi = {10.1016/j.cplett.2015.09.025},
issn = {0009-2614},
year = {2015},
date = {2015-01-01},
journal = {Chemical Physics Letters},
volume = {639},
pages = {172-177},
publisher = {2015 Elsevier B.V.},
abstract = {A series of zinc phthalocyanine dyes with different electron-donating and electron-withdrawing substituents and using the COOH as the anchor group that interacts with the semiconductor (TiO2) surface, were studied employing DFT and TDDFT methodologies. Their HOMO and LUMO orbital energies and, the redox mediator position would facilitate the injection process toward the conduction band of TiO2. We tested the effect of some electron-donating or electron-withdrawing substituents over zinc phthalocyanine dyes in terms of the Hammett parameters (Sigma sigma). We obtained a linear correlation between the substituents properties versus the free energy change of the electron-injection (Delta G(inject)) process.},
keywords = {approximation, conversion, electronic-structure, hammett organic-dyes, parameters, porphyrins properties, spectroscopic states, surface, tio2},
pubstate = {published},
tppubtype = {article}
}

@article{RN93,
title = {Photocatalytic Thin Films Containing Tio2:N Nanopowders Obtained by the Layer-by-Layer Self-Assembling Method},
author = { L. Rojas-Blanco and M. Urz\'{u}a and R. Ramirez-Bon and F.J.E. Beltran},
url = {/brokenurl#<Go to ISI>://WOS:000298670300042},
doi = {10.1016/j.apsusc.2011.03.150},
issn = {0169-4332},
year = {2012},
date = {2012-01-01},
journal = {Applied Surface Science},
volume = {258},
number = {6},
pages = {2103-2106},
publisher = {2011 Elsevier B. V.},
abstract = {In this work, TiO2-N powders were synthesized by high-energy ball milling, using commercial titanium dioxide (TiO2) in the anatase phase and urea to introduce nitrogen into TiO2 in order to enhance their photocatalytic properties in the visible spectral region. Several samples were prepared by milling a mixture of TiO2-urea during 2, 4, 8, 12 and 24 h and characterized by spectroscopic and analytical techniques. X-ray diffraction (XRD) results showed the coexistence of anatase and high-pressure srilankite TiO2 crystalline phases in the samples. Scanning electron microscopy (SEM) revealed that the grain size of the powder samples decreases to 200 nm at 24 h milling time. UV-Vis diffuse reflectance spectroscopic data showed a clear red-shift in the onset of light absorption from 387 to 469 nm as consequence of nitrogen doping in the samples. The photocatalytic activity of the TiO2-N samples was evaluated by methylene blue degradation under visible light irradiation. It was found that TiO2-N samples had higher photocatalytic activity than undoped TiO2 samples, which could be assigned to the effect of introducing N atoms and XPS results confirm it. Using polyethylenimine (PEI), transparent thin films of TiO2-N nanoparticles were prepared by layer-by-layer self assembly method. UV-visible spectrophotometry was employed in a quantitative manner to monitor the adsorbed mass of TiO2 and PEI after each dip cycle. The adsorption of both TiO2 and PEI showed a saturation dip time of 15 min.},
keywords = {by degradation, doping, layer layer, nitrogen nitrogen-doped oxide, photocatalysis, photoelectrochemical properties, srilankite, tio2, titanium urea},
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}
}