The Experts below are selected from a list of 34278 Experts worldwide ranked by ideXlab platform
Hiromasa Nishikiori - One of the best experts on this subject based on the ideXlab platform.
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observation of photoinduced proton transfer between the titania surface and Dye Molecule
Journal of Physical Chemistry C, 2020Co-Authors: Hiromasa Nishikiori, Hayato Kondo, Yosuke Kageshima, Nasrin Hooshmand, Sajanlal R Panikkanvalappil, David A Valverdechavez, Carlos Silva, Mostafa A Elsayed, Katsuya TeshimaAbstract:The photocatalyst titania film surface acquires a high hydrophilicity after it is exposed to UV light, which is induced by changes in the densities of the surface hydroxyl groups and charge. A xanthene Dye, fluorescein, was deposited from a solution onto a titania film after UV irradiation in order to probe the titania surface change. The change in the surface acidity was confirmed by the ratio of the dianion to monoanion of fluorescein by Raman spectroscopy. The ratio increased by the UV irradiation, indicating that the surface became more basic. Transient absorption spectroscopy revealed the transformation from the monoanion to the dianion via the excited states, i.e., photoinduced proton transfer from the fluorescein to the titania surface. The UV irradiation increases the basic hydroxyl groups on the titania surface, which accepts protons from the water Molecules or proton donors on the surface and has a positive charge.
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observation of photoinduced proton transfer between the titania surface and Dye Molecule
The Journal of Physical Chemistry, 2020Co-Authors: Hiromasa Nishikiori, Hayato Kondo, Yosuke Kageshima, Nasrin Hooshmand, Sajanlal R Panikkanvalappil, David A Valverdechavez, Carlos Silva, Mostafa A Elsayed, Katsuya TeshimaAbstract:The photocatalyst titania film surface acquires a high hydrophilicity after it is exposed to UV light, which is induced by changes in the densities of the surface hydroxyl groups and charge. A xanthene Dye, fluorescein, was deposited from a solution onto a titania film after UV irradiation in order to probe the titania surface change. The change in the surface acidity was confirmed by the ratio of dianion to monoanion of fluorescein by Raman spectroscopy. The ratio increased by UV irradiation, indicating that the surface became more basic. Transient absorption spectroscopy revealed the transformation from the monoanion to dianion via the excited states, that is, photoinduced proton transfer from fluorescein to the titania surface. The UV irradiation increases the basic hydroxyl groups on the titania surface, which accepts protons from the water Molecules or proton donors on the surface and has a positive charge.
Sheng Hsien Lin - One of the best experts on this subject based on the ideXlab platform.
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enhanced photovoltaic performance of Dye sensitized solar cells by the adsorption of zn porphyrin Dye Molecule on tio2 surfaces
Journal of Alloys and Compounds, 2019Co-Authors: Yanming Lin, Chaoyuan Zhu, Zhenyi Jiang, Yali Zhao, Qi Wang, Ruiqin Zhang, Sheng Hsien LinAbstract:Abstract The electronic structure, optical absorption and charge transfer performances of Zn-porphyrin (ZnPP) Dye Molecule adsorbed on anatase (101) and rutile (110) TiO2 surfaces have been investigated systematically using spin-polarized density functional theory calculations. The calculated results indicate that the strong interactions of ZnPP Dye Molecule and TiO2 surfaces cause an obvious variation of the conduction band minimum and valence band maximum for ZnPP Dye Molecule adsorbed on TiO2 surfaces, and the valence band of adsorption systems has a large bandwidth compared with that of the TiO2 bulk and surfaces, which induces a red-shift of the optical absorption edge and improves greatly the optical absorption of adsorption systems in the ultraviolet and visible light regions. Moreover, the change of charge density indicates that the photoelectrons transfer from the ZnPP Dye Molecule to TiO2 across the interface, and a built-in electric field is formed at the interface, which effectively enhances the separation of photogenerated electron-hole pairs. These results suggest that the sensitized actions of ZnPP Dye Molecule on TiO2 surfaces can generate an excellent photovoltaic performance of TiO2 photoanode in DSSCs.
André D. Taylor - One of the best experts on this subject based on the ideXlab platform.
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Colorful Organic Solar Cells Employing Förster Resonance Energy Transfer Dye Molecule
2018 IEEE 7th World Conference on Photovoltaic Energy Conversion (WCPEC) (A Joint Conference of 45th IEEE PVSC 28th PVSEC & 34th EU PVSEC), 2018Co-Authors: Jaemin Kong, Nilay Hazari, Megan Mohadjer Beromi, André D. TaylorAbstract:We demonstrate color tunable polymer solar cells by employing an energy transfer Dye Molecule in a polymerpolymer binary photoactive system. The guest Dye Molecule functions as energy transfer donor to the host photoactive system allowing the solar cell color to range from blue green to purple red without any significant efficiency decrease. In this proceeding we re-empathize the importance of the results and discussions which were published in Nano Energy in 2017 [1].
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Colorful polymer solar cells employing an energy transfer Dye Molecule
Nano Energy, 2017Co-Authors: Jaemin Kong, Megan Mohadjer Beromi, Tenghooi Goh, Marina Mariano, Francisco Antonio, Nilay Hazari, André D. TaylorAbstract:Over the past decade, there has been significant improvement in the performance of polymer solar cells (PSCs). Devices with power conversion efficiency (PCE) well over 10% have been developed and in some cases the estimated device lifetime is approaching 10 years. In contrast, there has been limited research into the aesthetics of PSCs, which may be crucial to successful commercialization. Here, we report a variety of colored polymer solar cells by employing different amounts of an energy transfer Dye Molecule in a polymer-polymer binary photoactive system. In fact, by varying the amount of the Dye Molecule in the device, PSCs covering one third of the Munsell standard color chart (in this case green to red) are observed. Additionally, the Dye Molecule serves as an energy transfer donor to the host photoactive system which leads to 10% enhancement in PCE. Our approach may broaden the appeal of PSCs in applications where aesthetics are important.
Takayoshi Kobayashi - One of the best experts on this subject based on the ideXlab platform.
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circa conservation of vibrational energy among three strongly coupled modes of a cyanine Dye Molecule studied by quantum beat spectroscopy with a 7 fs laser
Chemical Physics Letters, 2008Co-Authors: Takayoshi Kobayashi, Ying Wang, Zhuan Wang, Izumi IwakuraAbstract:Real-time energy exchange among the three vibrational modes forming a triplet with frequencies x1, x2, and x3 satisfying a ‘circa sum-frequency relation’, namely x1 + x2 ffi x3 in a cyanine Dye Molecule has been studied with a 7-fs pulse laser. There are two triplets with average frequencies of the components of (146, 279, 432 cm � 1 ) and (279, 432, 738 cm � 1 ). Even though the circa sum-frequency relation is satisfied, circa-conservation of the vibrational energy holds among the three components only in the latter triplet. The difference between the two is ascribed to the symmetry of the molecular vibrational modes. 2008 Elsevier B.V. All rights reserved.
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wave packet dynamics in a cyanine Dye Molecule excited with femtosecond chirped pulses
Journal of Chemical Physics, 2000Co-Authors: Kazuhiko Misawa, Takayoshi KobayashiAbstract:Femtosecond vibrational wave-packet dynamics in a cyanine Molecule is observed to be strongly dependent on the chirp direction of the excitation pulse. The slow-decay component associated with an oscillatory structure, which corresponds to the excited-state lifetime and a vibrational mode of 160±10 cm−1, respectively, is measured by the femtosecond time-resolved transmission spectroscopy. The excited-state population is substantially decreased and enhanced in the cases of negatively chirped (NC) and positively chirped (PC) excitations, respectively. A quantum mechanical calculation by means of the split operator scheme is performed to reproduce the wave-packet propagation after the chirped pulse excitation. The calculation shows that the spatial distribution of the wave packet for the NC case is narrower than that for the PC case during the excitation, and that the overlap integral between the excited- and ground-state wave packets determines the efficiency of the population dumping.
Koji Kimoto - One of the best experts on this subject based on the ideXlab platform.
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Microscopic observation of Dye Molecules for solar cells on a titania surface.
Scientific reports, 2016Co-Authors: Shogo Koshiya, Shunsuke Yamashita, Koji KimotoAbstract:The lateral distribution and coverage of Ru-based Dye Molecules, which are used for Dye-sensitized solar cells (DSCs), were directly examined on a titania surface using high-resolution scanning transmission electron microscopy (STEM). The clean surface of a free-standing titania nanosheet was first confirmed with atomic resolution, and then, the nanosheet was used as a substrate. A single Dye Molecule on the titania nanosheet was visualized for the first time. The quantitative STEM images revealed an inhomogeneous Dye-Molecule distribution at the early stage of its absorption, i.e., the aggregation of the Dye Molecules. The majority of the titania surface was not covered by Dye Molecules, suggesting that optimization of the Dye Molecule distribution could yield further improvement of the DSC conversion efficiencies.
