The effect of local environment on photoluminescence: a TD-DFT study of silanone groups on the surface of silica nanostructures
| Autor: | Zwijnenburg, M. A., Sokol, A. A., Sousa Romero, Carmen, Bromley, Stefan Thomas |
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| Jazyk: | angličtina |
| Rok vydání: | 2009 |
| Předmět: | |
| Zdroj: | Dipòsit Digital de la UB Universidad de Barcelona |
| Popis: | The optical absorption spectrum and lowest photoluminescence PL signal for silanone terminated silica nanostructures are studied using time-dependent density functional theory calculations on a range of realistic low energy silica nanocluster models. We show that the broad experimental absorption spectrum for silanone centers V. A. Radtsig and I. M. Senchenya Russ. Chem. Bull. 45, 1849 1996 is most likely the result of a synergetic combination of inhomogeneous broadening, thermal broadening and the small energy differences between different excitations. We further demonstrate that upon relaxation of the excited state the excited electron and hole localize on only one silanone center, and that there is a clear and distinct link between the local environment of a silanone center and its absorption and PL spectra. Finally, we provide strong evidence that the silanone center does not have a double bond between the constituent silicon and oxygen atoms but rather can be probably more aptly described as the =Si+-O− charge-transfer species. |
| Databáze: | OpenAIRE |
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