Figure 1.

Optical absorption and RRS characterization of SQ encapsulation in SWCNTs. Normalized absorption spectra of the (a) LV950 and (b) LV950-ATPE samples. SQ@SWCNT samples are denoted by red traces and reference DCM@SWCNT samples by black traces. The spectrum for the encapsulated SQ dye, obtained by subtraction of the DCM@SWCNT spectrum from the SQ@SWCNT spectrum, is identified by the blue traces. The spectrum for free SQ dye in toluene is denoted by the green trace. Ranges for the excitonic transitions for semiconducting (S₁₁, S₂₂, S₃₃) and metallic (M₁₁) SWCNTs and phonon side bands (X₁₁) are indicated, and the region where a strong D₂O absorption band complicates the background subtraction is identified by an asterisk. (c) Absorbance contribution due to encapsulated SQ for all five SWCNT samples, estimated by subtraction of the DCM@SWCNT spectrum from the SQ@SWCNT spectrum and compared to the absorption spectrum of SQ freely dissolved in toluene. (d) Raman spectra of the SQ@LV950 (red trace) and DCM@LV950 (black trace) samples excited at 676.4 nm. The spectrum of encapsulated SQ (blue trace) is obtained by subtracting the Raman spectra of DCM@LV950 from the SQ@LV950 spectrum (see SI, section 6, for other excitation wavelengths). The Raman spectrum of the pure SQ powder (gray trace) obtained at 514.5 nm is also shown.