Dispersion and Solvation Effects on the Structure and Dynamics of N719 Adsorbed to Anatase Titania (101) Surfaces in Room-Temperature Ionic Liquids: An ab Initio Molecular Simulation Study
KAUST DepartmentPhysical Sciences and Engineering (PSE) Division
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AbstractAb initio, density functional theory (DFT)-based molecular dynamics (MD) has been carried out to investigate the effect of explicit solvation on the dynamical and structural properties of a [bmim][NTf2] room-temperature ionic liquid (RTIL), solvating a N719 sensitizing dye adsorbed onto an anatase titania (101) surface. The effect of explicit dispersion on the properties of this dye-sensitized solar cell (DSC) interface has also been studied. Upon inclusion of dispersion interactions in simulations of the solvated system, the average separation between the cations and anions decreases by 0.6 Å; the mean distance between the cations and the surface decreases by about 0.5 Å; and the layering of the RTIL is significantly altered in the first layer surrounding the dye, with the cation being on average 1.5 Å further from the center of the dye. Inclusion of dispersion effects when a solvent is not explicitly included (to dampen longer-range interactions) can result in unphysical "kinking" of the adsorbed dye's configuration. The inclusion of solvent shifts the HOMO and LUMO levels of the titania surface by +3 eV. At this interface, the interplay between the effects of dispersion and solvation combines in ways that are often subtle, such as enhancement or inhibition of specific vibrational modes. © 2015 American Chemical Society.
CitationByrne A, English NJ, Schwingenschlögl U, Coker DF (2016) Dispersion and Solvation Effects on the Structure and Dynamics of N719 Adsorbed to Anatase Titania (101) Surfaces in Room-Temperature Ionic Liquids: An ab Initio Molecular Simulation Study . The Journal of Physical Chemistry C 120: 21–30. Available: http://dx.doi.org/10.1021/acs.jpcc.5b08964.
SponsorsThe authors thank Dr. Clotilde Cucinotta, Dr. Marco Masia, and Dr. Pietro Ballone for useful discussions. This research has been supported by the Programme for Research in Third Level Institutions (PRTLI) Cycle 5 and cofunded by the European Regional Development Fund. We thank SFI, ICHEC, and KAUST for the provision of high-performance computing facilities. We also wish to thank Prof. Adrian Ottewill and the UCD Simulation Science Programme, the Erasmus Mundus Gulf Programme, and the EU Commission Marie Curie RISE "ENACT" Programme (grant number 643998). Research reported in this publication was supported by the King Abdullah University of Science and Technology (KAUST).
PublisherAmerican Chemical Society (ACS)