Red-Shift Effects in Surface Enhanced Raman Spectroscopy: Spectral or Intensity Dependence of the Near-Field?
|Author(s)||Colas Florent1, 2, Cottat Maximilien2, Gillibert Raymond2, Guillot Nicolas2, Djaker Nadia2, Lidgi-Guigui Nathalie2, Toury Timothee3, Barchiesi Dominique4, Toma Andrea5, Di Fabrizio Enzo6, 7, 8, Gucciardi Pietro G.9, De La Chapelle Marc Lamy2|
|Affiliation(s)||1 : Detect Sensors & Measurements Lab, Technol Res & Dev Dept, IFREMER, F-29280 Plouzane, France.
2 : Univ Paris 13, Sorbonne Paris Cite, Lab CSPBAT, CNRS,UMR 7244, 74 Rue Marcel Cachin, F-93017 Bobigny, France.
3 : Univ Technol Troyes, UMR STMR CNRS 6279, ICD LNIO, 12 Rue Marie Curie, F-10000 Troyes, France.
4 : Univ Technol Troyes, Project UTT INRIA Gamma3, Project Grp Automat Mesh Generat & Adv Methods, 12 Rue Marie Curie, F-10000 Troyes, France.
5 : Ist Italiano Tecnol, Via Morego 30, I-16163 Genoa, Italy.
6 : King Abdullah Univ Sci & Technol, KAUST, Phys Sci & Engn Div, Thuwal 239556900, Saudi Arabia.
7 : King Abdullah Univ Sci & Technol, KAUST, BESE Div, Thuwal 239556900, Saudi Arabia.
8 : Magna Graecia Univ Catanzaro, BIONEM Lab, Campus Salvatore Venuta,Viale Europa, I-88100 Germaneto Catanzaro, Italy.
9 : CNR IPCF Ist & Proc Chim Fis, Viale F Stagno DAlcontres 37, I-98156 Messina, Italy.
|Source||Journal Of Physical Chemistry C (1932-7447) (Amer Chemical Soc), 2016-06 , Vol. 120 , N. 25 , P. 13675-13683|
|WOS© Times Cited||15|
|Abstract||Optimum amplification in Surface Enhanced Raman Scattering (SERS) from individual nanoantennas is expected when the excitation is slightly blue-shifted with respect to the Localized Surface Plasmon Resonance (LSPR), so that the LSPR peak falls in the middle between the laser and the Stokes Raman emission. Recent experiments have shown when moving the excitation from the visible to the near-infrared that this rule of thumb is no more valid. The excitation has to be red-shifted with respect to the LSPR peak, up to 80nm, to obtain highest SERS. Such discrepancy is usually attributed to a Near-Field (NF) to Far-Field (FF) spectral shift. Here we critically discuss this hypothesis for the case of gold nanocylinders. By combining multi-wavelength excitation SERS experiments with numerical calculations, we show that the red-shift of the excitation energy does not originate from a spectral shift between the extinction (FF) and the near-field distribution (NF), which is found to be not larger than 10nm. Rather, it can be accounted for by looking at the peculiar spectral dependence of the near-field intensity on the cylinders diameter, characterized by an initial increase, up to 180nm diameter, followed by a decrease and a pronounced skewness.|