Добірка наукової літератури з теми "Ruthenium based-photosensitizer"

In this study, a novel photosensitizer having two perylenediimide units and a phenanthroline ruthenium(ii) coordination moiety (Ru-BP)has been developed for photodynamic therapy (PDT) of cancer cells.

Three thiocyanate-free ruthenium (II) sensitizers, [RuII(dcppy)(L1-L3)](PF6)] where dcppy = 4, 4-dicarboxylic acid-2, 2-bipyridine, L1 = 2-(2,4-difluorophenyl)-5-(trifluoromethyl) pyridine, L2 = 2-(2,4-difluorophenyl) pyridine and L3 = 2-phenyl-5-(trifluoromethyl) pyridine were synthesized and applied for dye-sensitized solar cells (DSSCs). The structures of ruthenium complexes were characterized by 1H, 13C NMR and IR spectra. The absorption was studied by UV-Vis spectroscopy and the electrochemical property was determined by cyclic voltammetry. The surface morphology of ruthenium complexes on mica was examined by atomic force microscopy. The performance of this complexes as photosensitizer in TiO2 based dye sensitized solar cells is studied under standard AM 1.5 sunlight and by using an electrolyte.

Since early 1990s dye-sensitized solar cells (DSSC) has been developed by many research groups all over the World. This paper presents a review of researches focusing on photosensitizer influence on DSSC efficiency. Variety of dye substance has been analyzed. The highest efficiency around 11.2% has been noted for ruthenium-based DSSC devices. Natural dyes allowed to reach 4.6%. The most metal-free organic dyes resulted in efficiency ranged from 5% to 9%, however, some of them (e.g. Y123) allowed to obtain devices with efficiencies equal to 10.3%. Co-sensitization is the new approach which results in efficiencies up to 14.3%.

We investigated regulation of intracellular Ca2+ induced by photodynamic therapy (PDT) with a new chlorin-based photosensitizer, DH-II-24, in human gastric adenocarcinoma cells. DH-II-24-mediated PDT induced necrotic cell death according to post-irradiation time, and produced intracellular reactive oxygen species (ROS) in an irradiation time-dependent manner. PDT also increased intracellular Ca2+ , and this Ca2+ elevation was largely inhibited by BAPTA-AM but not by EGTA. BAPTA-AM inhibited the ROS production by PDT, whereas NAC and Trolox had no effect on the PDT-induced Ca2+ response. In the presence of EGTA, pre-incubation with thapsigargin, Gly-Phe-β-naphthylamide or brefeldin A had no significant effect on the PDT-induced elevation in intracellular Ca2+ . However, ruthenium red affected the initial and late Ca2+ responses to PDT. Thus, DH-II-24-mediated PDT produces intracellular ROS via elevation in intracellular Ca2+ , contributed, at least in part, by mitochondria, which results in necrotic death of the human gastric adenocarcinoma cells.

Dye-sensitized photoelectrochemical cells based onTiO2mesoporous films, a ruthenium bipyridyl derivative as photosensitizer and aSiO2/poly(ethylene glycol)-200 nanocomposite thin film as electrolyte support, have been constructed.TiO2films have been deposited on conductive transparent Indium-Tin Oxide glass slides by means of a sol-gel procedure carried out in reverse-micellar solutions. The photosensitizer has been adsorbed on titania films from ethanolic solutions while the electrolyte layer has been synthesized by a sol-gel procedure. The presence of silica in the nanocomposite electrolyte gel provides the gelifying agent, the compound that holds the cell together in a sandwich form and the sealing agent that protects the cell and secures its long-term function. PEG-200 makes the organic subphase which provides the ionic conductivity. The present work describes the construction of the cell and the study of its efficiency. A variant of the cell has also been made by incorporatingAg+andRu3+ions into titania particles, but these dopants did not improve cell efficiency, either in their oxidized or in their reduced form.

Dans ce travail, différents systèmes catalytiques nanostructurés ont été synthétisés par une approche organométallique pour obtenir des nanoparticules de petite taille et de distribution de taille étroite, et leur activité catalytique dans la réaction d'oxydation de l'eau a été évaluée. Premièrement, des NPs de fer stabilisées par l'acide oléique ont été synthétisées qui présentaient une taille moyenne d'env. 10 nm ± 1,1 nm. Une couche d'oxyde, gamma-Fe_2O_3, d'env. 2,6 nm d'épaisseur a été formée à leur surface pour obtenir des structures cœur-coquille Fe@FeOx d'env. 11,5 ± 2,3 nm de diamètre. Malgré leur hydrophobicité, ces nanoparticules ont montré une bonne activité électrocatalytique en conditions alcalines. La coquille d'oxyde gamma-Fe_2O_3 étant bien adaptée au greffage de groupements phosphoniques, ces NPs Fe@FeOx ont été greffées avec différents acides aminophosphoniques afin de les transférer dans l'eau. Une évaluation préliminaire de leur activité catalytique montre une amélioration lorsque les NPs sont greffées avec l'acide 3-aminopropyl phosphonique, ce qui ouvre des perspectives prometteuses. En outre, un photosensibilisateur, un complexe Ru-phénanthroline avec un groupe phosphonate pendant, a été synthétisé et greffé sur les NPs Fe@FeOx pour former une photoanode hybride et catalyser la photoélectrodécomposition de l'eau. Des processus mono et biphasiques ont été étudiés pour greffer le complexe à la surface des nanoparticules. Le processus monophasique s'est avéré plus efficace car il a fourni une densité de greffage plus élevée (respectivement 56 et 9 Ru par NP pour les processus mono et biphasiques). Des mesures photoélectrochimiques ont montré que le nanocatalyseur hybride comprenant la teneur en Ru la plus élevée était env. 9 fois plus actif qu'un simple mélange entre un photosensibilisateur au ruthénium sans fonction de greffage et les nanoparticules Fe@FeOx, et env. 40 fois plus actif que les NPs Fe@FeOx. L'amélioration des performances pourrait être attribuée à un transfert d'électrons plus efficace entre le photosensibilisateur et le catalyseur Fe@FeOx grâce à la liaison covalente entre ces deux composants. Le greffage covalent s'est avéré améliorer non seulement l'activité photocatalytique mais également la stabilité du système. Enfin, des NPs NiFe amorphes (diamètre env. 4 nm) avec deux compositions différentes (Ni_0,5Fe_0,5 NPs et Ni_0,68Fe_0,32 NPs) ont été synthétisées, oxydées à l'air et fonctionnalisées avec de l'acide 3-aminopropyl phosphonique. L'activité électrocatalytique de ces NP hydrosolubles a été étudiée en milieu alcalin, en comparaison avec des NPs NiOx, FeOx et Ni_0.1Fe_0.9Ox. Les NPs hydrosolubles contenant 32% de Fe (Ni_0,68Fe_0,32Ox) ont montré l'activité la plus élevée et une bonne durabilité en solution alcaline. Ces caractéristiques rendent ces NP amorphes potentiellement applicables dans les cellules photoélectrochimiques pour la photodécomposition de l'eau
In this work, different nanostructured catalytic systems have been synthesized by an organometallic approach to produce nanoparticles (NPs) of small size and narrow size distribution, and their catalytic activity in the water oxidation reaction has been evaluated. First Fe NPs stabilized by oleic acid were synthesized that displayed an average size of ca. 10 nm ± 1.1 nm. A gamma-Fe_2O_3 oxide layer ca. 2.6 nm thick has been formed at their surface to obtain Fe@FeOx core-shell structure of ca. 11.5 ± 2.3 nm in diameter. Despite their hydrophobicity, these nanoparticles showed good electrocatalytic activity in alkaline conditions. As the gamma-Fe_2O_3 oxide shell is well adapted to the grafting of phosphonic groups, these Fe@FeOx NPs were grafted with different aminophosphonic acids in order to transfer them into water. Preliminary assessment of their catalytic activity showed improved activity for the NPs functionalized by 3-aminopropylphosphonic acid which opens promising prospects. Subsequently, a Ru-phenanthroline light-harvester with a pendant phosphonate group was synthesized and grafted onto the Fe@FeOx core/shell NPs to afford a novel hybrid photoanode for solar-driven water splitting. Mono- and biphasic processes were investigated to graft the Ru-complex at the surface of the NPs. The monophasic process was found to be more efficient as it provided a higher grafting density at the surface of the NPs (respectively 56 and 9 Ru per nanoparticles for the mono and biphasic processes). Photoelectrochemical measurements showed that the hybrid nanocatalyst comprising the highest Ru content was ca. 9-fold more catalytically active than a simple mixture between a ruthenium polypyridyl photosensitizer bearing no grafting group and the Fe@FeOx nanoparticles, and 40-fold more active than the pristine Fe@FeOx NPs. The performance enhancement could be attributed to a more efficient electron transfer between the ruthenium polypyridyl photosensitizer and the Fe@FeOx water oxidation catalyst thanks to the covalent bonding between these two components. The covalent grafting was found to improve not only the photocatalytic activity but also the stability of the system. Finally, amorphous NiFe NPs (diameter ca. 4 nm) with two different ratios between Ni and Fe (Ni_0.5Fe_0.5 NPs and Ni_0.68Fe_0.32 NPs) were synthesized, oxidized in air and grafted with 3-aminopropylphosphonic acid in order to obtain hydrophilic systems. The electrocatalytic activity of these water-soluble NPs was studied in alkaline solution, in comparison with that of crude NiOx NPs, FeOx NPs, and Ni_0.1Fe_0.9Ox NPs. The water soluble NPs containing 32 % of Fe (Ni_0.68Fe_0.32Ox) showed the highest activity and a good durability in alkaline solution. These characteristics make these amorphous NPs potentially applicable in photoelectrochemical cells for water splitting

碩士
國立中央大學
化學研究所
95
Two new ruthenium complexes (SJW-E1, and CYC-B3) with the general chemical formula of [Ru(dcbpy)(L)(NCS)2] where dcbpy is 4,4’-dicarboxylic acid-2,2’-bipyridine and L is 4,4’-bis-(4’-octyl-3,4- ethylenedioxythiophene-2-yl)-2,2’-bipyridine or 4,4’-bis-(4’-octyl-tri- thiophen-2-yl)-2,2’-bipyridine were prepared and well characterized. The performance of these two dye sensitized dye-sensitized solar cells (DSCs) was also explored. These complexes were synthesized via the typical one-pot synthesis and identified with NMR, IR and Mass spectroscopies. In addition, the localizations of HOMOs and LUMOs of these Ru-complexes were calculated with the semi-empirical computation (ZINDO/1) in order to understand the effects of the frontier orbitals on the light harvesting capability of the photosensitizers. Under the illumination of AM1.5 stimulated light, the photon-to-current conversion efficiency of SJW-E1 and CYC-B3 sensitized cells was 9.02 % and 7.39 % whereas 8.42 % is obtained for the N3 sensitized cell. The efficiency of SJW-E1 sensitized solar cell is higher than that of CYC-B3 sensitized solar cell, because of the ethylene-dioxy group on the ancillary ligand of SJW-E1 is able to offer extra conjugated length to thiophene. Therefore, the SJW-E1 has its λmax more red-shifted and higher absorbance coefficient compared to CYC-B3. In addition, the ethylene-dioxy group could avoid electron-hole recombination due to its good electron donating ability. These characteristics make SJW-E1 a good photesensitizer for DSCs.