Influence of Ag nanoparticle size and configuration on the sers signal of (CN)2 (PH)3
| Autor: | Baraldi, G., López-Tobar, Eduardo, Sánchez-Cortés, Santiago, Gonzalo, J. |
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| Rok vydání: | 2013 |
| Zdroj: | Digital.CSIC. Repositorio Institucional del CSIC instname |
| Popis: | Nanostructures containing noble metal nanoparticles (NPs) are of great interest as substrates for surface enhanced vibrational Raman scattering and infrared absorption spectroscopies (SERS and SEIRA) since they are appropriate for building lab-on-a-chip sensors. In particular, the excitation of the Surface Plasmon Resonance (SPR) at specific wavelengths by external electromagnetic (EM) fields, and the consequent intensification of EM field in the vicinity of the NP allows a huge enhancement of the signal in the case of SERS. In this work, we study the dependence of the SERS signal of Triphenylene dicyanide ((CN)2 (PH)3) as a function of the configuration and size of Ag NPs. Either the molecule is suspended in a colloid containing Ag NPs (Ø=40 nm) or the molecule is deposited, by solution, on nanostructures consisting of Ag NPs deposited on amorphous Al2O3 layers grown by Pulser Laser Deposition. Two different NP sizes have been considered in this case (Ø=20 and 100 nm). In all cases, the peak of the SPR matches the SERS probing laser wavelength (¿=530 nm) to guarantee the largest enhancement. SERS spectra show that the molecule strongly attaches to colloidal Ag NPs as well as to the smallest NPs on the nanostructures, although the SERS signal is detected at different wavenumbers. However, no signal is observed for the largest NPs on the nanostructures. We discuss these results in terms of molecule orientation and size and distribution of Ag NPs in the case of the nanostructures |
| Databáze: | OpenAIRE |
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