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Takeuchi I.,Japan National Institute of Advanced Industrial Science and Technology | Asaka K.,Japan National Institute of Advanced Industrial Science and Technology | Kiyohara K.,Japan National Institute of Advanced Industrial Science and Technology | Sugino T.,Japan National Institute of Advanced Industrial Science and Technology | And 2 more authors.
Journal of Physical Chemistry C | Year: 2010

In this paper, bucky-gel electrodes containing various ionic liquid species were prepared by casting, using "bucky gel", a gelatinous room-temperature ionic liquid (IL) containing single-walled carbon nanotubes (SWCNT). Their electrochemical impedance responses were measured and analyzed. Also, the electromechanical responses of the actuators composed of two bucky-gel electrodes sandwiching an ionic liquid gel layer were studied by measuring the displacement due to an applied sinusoidal voltage at various frequencies. All impedance data were successfully simulated by the equivalent circuit model of a porous electrode based on the transmission line circuit model. By using the same parameter values of the porous electrode model, the frequency dependence of the strain generated in the bucky-gel actuators can be simulated. On the basis of the experimental and simulation results, the electromechanical responses of the bucky-gel actuator were analyzed by taking into account the electrochemical properties of the bucky-gel electrode. Accordingly, an electromechanical model for a bucky-gel actuator was obtained. © 2010 American Chemical Society. Source


Zheng R.,Lanzhou University | Shi Y.,Lanzhou University | Jia Z.,Lanzhou University | Zhao C.,Lanzhou University | And 4 more authors.
Chemical Society Reviews | Year: 2010

This tutorial review highlights the mechanism of a novel non-enzymatic fast repair of DNA damage, which refers exclusively to repair DNA radicals including DNA-OH adducts, DNA radical cations and anions by various endogenous, natural and synthetic compounds. The repair rate constants are as high as 109 M-1 s-1. In cells, when the enzymatic repair system was inhibited or before the enzymatic repair mechanism was initiated, DNA oxidative damage was significantly reduced by natural polyphenols. This decrease of DNA damage is assigned to the fast repair. Fast repair takes place through an electron transfer process, and docking of polyphenol into the DNA minor groove could be the essential step. © 2010 The Royal Society of Chemistry. Source


Perrier A.,CNRS Laboratory of Interfaces, Processing, Organization and System Dynamics | Maurel F.,CNRS Laboratory of Interfaces, Processing, Organization and System Dynamics | Ciofini I.,Ecole Nationale Superieure de Chimie de Paris | Jacquemin D.,University of Nantes | Jacquemin D.,University of Namur
Chemical Physics Letters | Year: 2011

This Letter is a theoretical investigation of the ground and excited-state properties of diarylethenes coupled through a platinum-containing bridge. Our simulations are performed using (Time-Dependent) Density Functional Theory in conjunction with the Polarisable Continuum Model and aim at characterising the coupling between the two photochromes. It turns out that theory provides results in very good agreement with experiment for the IR, NMR and UV/Vis spectroscopies. The states and orbitals involved in the relevant UV transitions are analysed, allowing to obtain insights regarding the successive electro-cyclisations, the second probably using a triplet pathway. © 2010 Elsevier B.V. All rights reserved. Source


Perrier A.,CNRS Laboratory of Interfaces, Processing, Organization and System Dynamics | Maurel F.,CNRS Laboratory of Interfaces, Processing, Organization and System Dynamics | Jacquemin D.,University of Nantes
Journal of Physical Chemistry C | Year: 2011

The structures and electronic features of five complex multiphotochromic molecules incorporating two or three diarylethene units are investigated with quantum mechanical approaches. Four out of the five systems only display partial photochromism, and it is shown that the interplay between steric and electronic effects might explain this outcome. For a spiro-bonded system (I), the doubly closed isomer is reachable because the two photochromes are essentially independent and undergo no specific geometric stress. For a tetrathiafilvalene- bridged derivative (II), there is no steric hindrance, but promoting the electron toward the reactive orbital is not possible. In dimers sharing a central thiophene ring (III and IV), the absence of the closed-closed derivative can be understood by either the compactness of the molecule or by a combination of conformational and electronic (lack of photochromic orbital) factors. Eventually, the reactivity of the trimer, V, is related to the variations of the distances between reactive carbon atoms. This contribution therefore paves the way toward an atomic-scale description of elaborated coupled switches and gives hints for the design of more efficient multiaddressable structures, by proposing a new architecture. © 2011 American Chemical Society. Source


Le Bahers T.,Ecole Nationale Superieure de Chimie de Paris | Labat F.,Ecole Nationale Superieure de Chimie de Paris | Pauporte T.,Ecole Nationale Superieure de Chimie de Paris | Laine P.P.,CNRS Laboratory of Interfaces, Processing, Organization and System Dynamics | Ciofini I.,Ecole Nationale Superieure de Chimie de Paris
Journal of the American Chemical Society | Year: 2011

A step-by-step theoretical protocol based on density functional theory (DFT) and time-dependent DFT at both the molecular and periodic levels is proposed for the design of dye-sensitized solar cell (DSSC) devices including dyes and electrolyte additives. This computational tool is tested with a fused polycyclic pyridinium derivative as a novel dye prototype. First, the UV-vis spectrum of this dye alone is computed, and then the electronic structure of the system with the dye adsorbed on an oxide semiconductor surface is evaluated. The influence of the electrolyte part of the DSSC is investigated by explicitly taking into account the electrolyte molecules co-adsorbed with the dye on the surface. We find that tert-butylpyridine (TBP) reduces the electron injection by a factor of 2, while lithium ion increases this injection by a factor of 2.4. Our stepwise protocol is successfully validated by experimental measurements, which establish that TBP divides the electronic injection by 1.6 whereas Li + multiplies this injection by 1.8. This procedure should be useful for molecular engineering in the field of DSSCs, not only as a complement to experimental approaches but also for improving them in terms of time and resource consumption. © 2011 American Chemical Society. Source

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