Excitons at the (001) surface of anatase: Spatial behavior and optical signatures

Physical Review B 84, 073404 (BR) (2011)

Excitons at the (001) surface of anatase: Spatial behavior and optical signatures

G. Giorgi, M. Palummo, L. Chiodo, K. Yamashita,

Within an ab initio study, based on the application of Many-Body Perturbation Theory approaches on top of ground-state Density Functional Theory calculations, we study the optical behavior of the TiO2 anatase (001) surface. We focus on the (1 × 1) and the (1 × 4) reconstructions, both experimentally observed, which reveal a different optical response and an anisotropy, in the (001) plane, not present in the bulk phase. The determination of the spatial behavior of the electron-hole photoexcited couple provides a possible explanation of the observed enhanced photocatalytic activity of TiO2 anatase nanostructures with a high percentage of (001)-(1 × 1) exposed facets.

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We acknowledge the CINECA Award Nos.HP10BWKN81, 2010 and HP10BGKRNN, 2010 for the availability of high performance computing resources and support. M.P. and L.C. acknowledge E.C. e-I3 ETSF project (INFRA-2007-1.2.2:n.211956), G.G. the KAKENHI Grant (No. 21245004) and the Global COE Progr. Chem. Innov. from MECSST of Japan. Authors thank P. Monachesi for carefully reading the manuscript.

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