ABSTRACT
Abstract ................................................................................................. 136 7.1 Introduction .................................................................................. 136 7.2 Experimental ................................................................................ 137 7.3 Characterization ........................................................................... 138 7.4 Results and Discussion ................................................................ 140 7.5 Conclusions .................................................................................. 142 Keywords .............................................................................................. 142 References ............................................................................................. 143
ABSTRACT
In this contribution, we investigated the wavelength dependence of surface-enhanced Raman scattering (SERS) spectra of pyrene. For this purpose, three different excitation wavelengths have been applied: l=514.5 nm, l=647.0 nm and l=785.0 nm. To achieve comparable experimental conditions, tailor-made SERS substrates were prepared, consisting of silver or gold nanoparticles on sapphire supports. The tailoring is based on control of the mean shape and size of the nanoparticles, which permits a precise tuning of their localized surface plasmon polariton resonance in the vicinity of the excitation wavelength, used for the SERS measurements. We demonstrate that greatly enhanced SERS spectra were obtained for all wavelengths. However, only for the excitation wavelength of l=785 nm, almost background free SERS spectra of pyrene with an excellent signal-to-noise ratio were obtained.
