Identification of oxygen vacancy types from Raman spectra of SnO₂ nanocrystals

Raman spectra acquired from spherical SnO 2 nanocrystals prepared by pulsed laser ablation and hydrothermal synthesis exhibit three oxygen‐vacancy‐related Raman modes at 234, 573, and 618 cm −1 . The peak location and intensity vary with annealing temperature under O 2 finally approaching those of bulk materials. Density functional calculation discloses that the three Raman modes stem from subbridging, in‐plane, and bridging oxygen vacancies, respectively. Raman spectra can thus be used to discern different types of oxygen vacancies in SnO 2 nanocrystals.