Fluorescence Quenching of Raman Spectra by Carbon Materials

We focused on the fact that carbon materials have absorption in the visible light region, and attempted to suppress the increase in the baseline derived from fluorescence during Raman spectral measurements by utilizing this property. In the experiment, a sample of epoxy resin containing a fluorescent agent and carbon material was used. The relative Raman intensity was defined as the Raman intensity of the epoxy resin relative to the fluorescence intensity, and the effects of carbon material concentration and carbon species were investigated. The higher the relative Raman intensity, the more effective the suppression of fluorescence by the carbon material. The results of the study showed that carbon black exhibited the highest relative Raman intensity at a concentration of 3.0 mass % with respect to the sample, which suppressed the baseline increase due to fluorescence. Among the eight carbon materials, Ketjen black showed the highest relative Raman intensity. The absorption coefficients of the carbon materials in the visible light region were investigated, and the relative Raman intensity was higher for the carbon materials with higher absorption coefficients. Therefore, we speculate that the absorption of fluorescence by carbon materials is closely related to the suppression of baseline increase due to fluorescence using carbon materials.