Figure 1: Phase-dependent absorption spectra of CdSe NCs.
From: Optical determination of crystal phase in semiconductor nanocrystals
(a,b) XRD patterns of CdSe NCs with five different E0 transitions, matched between ZB (a) and WZ (b). Bulk patterns are shown below the experimental spectra with vertical dotted lines corresponding to the major diffraction peaks. (c) Experimental absorption spectra of ZB and WZ CdSe NCs, with matched E0 transitions. Prominent crystal phase-specific E1 bands are apparent at ∼4.9 eV for ZB and ∼5.1 eV for WZ. (d) Measured relationship between E0 and E1 for ZB (red triangles) and WZ (green circles) CdSe NCs with linear fits (black lines), showing little quantum confinement effects for E1 in comparison with E0 and a greater size-dependent shift of E1 for ZB compared with WZ. (e) DFT-simulated absorption coefficient (α) spectra of ZB (red) and WZ (green) CdSe NCs, showing similar E0 transitions and phase-distinct E1 bands in the 5–6 eV range. The structures used in the simulations are depicted in the plot inset.
