Probing plasmonic system by the simultaneous measurement of Raman and fluorescence signals of dye molecules

Abstract

Abstract. The simultaneous measurement of Raman and fluorescence signals was proposed to find out the molecule-metal distance. The ratio between Raman and fluorescence intensities was used to estimate molecule-metal distance in nanometer scale. A low-value intensity of the fluorescence of the dye molecules was found using the photobleaching effect. Made was a comparison of experimental results with a theoretical model, which showed well agreement.

Self-Organized SERS Substrates with Efficient Analyte Enrichment in the Hot Spots

“…In the previous works on SERS of fluorescent molecules (dyes), the ratio of the PL and Raman peak intensity in the SERS experiments has been shown to be proportional (average) to the distance between the plasmonic nanoparticle and analyte molecule. 82 , 83 Therefore, in our case, at a relatively high analyte concentration, presumably ≥10 –7 M for our type of substrates, the number of analyte molecules is much larger than the number of hot spots (which is constant for the given substrate). As a result, only a small fraction of the molecules gets located in the hot spots, where their Raman spectrum is greatly enhanced and PL is quenched.…”

Fluorescence of molecules placed near a spherical particle: Rabi splitting

“…A spectral shift [21] of molecular fluorescence near Ag surface was displayed too, however, it should be noted the other possible for the shift, namely, molecular aggregations. The decrease of the molecule fluorescence intensity, caused by the energy transfer to the metal surface, leads to a change of the ratio between Raman and fluorescence intensities [22] and was proposed to extract the enhancement factors of SERS [23] and to determine the fluorescence time [24] and molecule-metal distance [25,26]. If the resonance frequency ω r of ( )…”