Semiconductor crystals generally exhibit notable facet-dependent electrical conductivity and photocatalytic activity properties. If semiconductor nanocrystals of different shapes are available, their light absorption and emission bands can also display facet dependence, although bulk plus surface absorption combines to give the recorded spectra. All these physical phenomena can be understood, assuming a thin surface layer exists with slight structural deviations as predicted by density functional theory (DFT) calculations to give dissimilar band structures and hence different degrees of band bending and barriers to charge transport across a particular crystal face. This layer thereby tunes light absorption. Recent X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HR-TEM) analyses begin to suggest the presence of the proposed surface layer.