Surface-Enhanced Raman Scattering of a Single Nanodumbbell: Dibenzyldithio-Linked Silver Nanospheres
| Autor: | V. A. Apkarian, Mayukh Banik, A. Rodriguez Perez, N. Guarrotxena, Amit Nag, Patrick Z. El-Khoury, Guillermo C. Bazan |
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| Rok vydání: | 2012 |
| Předmět: |
Chemistry
Atomic force microscopy Analytical chemistry Surfaces Coatings and Films Electronic Optical and Magnetic Materials symbols.namesake Cross section (physics) General Energy Signal strength Polarizability symbols Molecule Physical and Theoretical Chemistry Polarization (electrochemistry) Raman spectroscopy Raman scattering |
| Zdroj: | The Journal of Physical Chemistry C. 116:10415-10423 |
| ISSN: | 1932-7455 1932-7447 |
| DOI: | 10.1021/jp302013k |
| Popis: | We describe combined AFM/Raman measurements on single nanodumbbells, consisting of silver nanospheres linked with dibenzyl-4,4′-dithiol (DBDT). The measured surface-enhanced Raman scattering (SERS) enhancement factor, EFexp = 3 × 107 at 532 nm, corresponds to the observed signal strength of a single DBDT molecule, the Raman cross section of which was determined to be dσ/dΩ = 6 × 10–28 cm2/sr. We show that the product of the local field enhancement, EFP = (Ei/E0)2(Es/E0)2= 3 × 106, and the chemical contribution due to reduced detuning, EFC = (Δ0/Δ)2 = 12, account for the observed effect. The chemical contribution is assessed by exploring model structures Agn–S–DB–S–Agm (n, m = 0, 3, 7, 20). The π–π* transition at 287 nm, which determines the polarizability of the bare molecule, acquires a DBDT-to-silver charge-transfer character upon binding to silver. The CT transition near 400 nm reduces the detuning but remains nonresonant at 532 nm. We observe a soft polarization dependence, which suggests optical acti... |
| Databáze: | OpenAIRE |
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