Absorption spectra of CdSe nanocrystals before and after ligand exchange.
Representative resonance Raman spectra of CdSe NCs in chloroform at the indicated excitation wavelengths. The LO phonon fundamental and overtone are labeled; the other three strong peaks are from the chloroform solvent. Concentrations are 22.9 μM for the 457.9 and 488 nm spectra and 8.86 μM for the 532 nm spectrum.
Total Raman spectrum (parallel plus perpendicular) in the LO fundamental region at two excitation wavelengths.
Comparison of the absorption spectrum (black curve, arbitrarily scaled), quantum yield for the LO Raman fundamental (blue, left-hand axis), and quantum yield for photoluminescence (red, right-hand axis).
Experimental and calculated absorption spectrum, fundamental Raman excitation profile, fundamental Raman depolarization ratio, and overtone to fundamental ratio for a model assuming an inhomogeneous width of 1000 cm−1 (FWHM) and three electronic transitions having center frequencies of 17 925, 19 025, and 21 850 cm−1, homogeneous widths of 50, 50, and 2900 cm−1, transition lengths of 2.54, 1.05, and 4.79 Å, and Huang-Rhys factors of 0.0021, 0.0021, and 0.91, respectively.
Same as Figure 5 , but assuming zero inhomogeneous broadening. The three electronic transitions have center frequencies of 17 925, 19 000, and 21 850 cm−1, homogeneous widths of 750, 1100, and 3000 cm−1, transition lengths of 2.47, 1.11, and 4.77 Å, and Huang-Rhys factors of 0.91, 0.405, and 1.05, respectively.
Experimental absorption spectrum and the eight components of the calculated absorption spectrum as given by the fitting parameters of Table I . Thick and thin lines indicate z-polarized and xy-polarized transitions, respectively. Grey, red, and blue curves represent states having zero, small, and large Huang-Rhys factors, respectively. The xy-polarized transitions are twice as intense as the corresponding z-polarized transitions because of their degeneracy.
Final modeling parameters. a
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