We believe that, for the first time, the UV-visible optical reflectivity of nanocrystalline ceria with various particle sizes has been measured, and their optical absorption characteristics have been studied by Kramers–Kronig transformation. The wide absorption band in the 200–480-nm range consisted of two narrow bands. This wide band was designated as the charge transfer of O2p–Ce4f while both narrow bands, which overlapped in this wide band, were due to the well-known 2F5/2–2F7/2 spin-orbit splitting of the Ce 4f1 state. With a decrease in the particle sizes of the samples, the bandwidth expanded distinctly and a red shift in the wide band was observed. On the other hand, the band gap between the narrow bands showed a remarkable increase. All of these phenomena resulted from the effects of quantum size and the interface of nanostructured materials.
© 1997 Optical Society of America
Liu Fangxin, Wang Chengyun, Su Qingde, Zhao Tianpeng, and Zhao Guiwen, "Optical properties of nanocrystalline ceria," Appl. Opt. 36, 2796-2798 (1997)