Optical Spectroscopy and Upconversion Studies of Ho3+-Doped Bulk and Nanocrystalline Y2O3

By J. Capobianco, J. Boyer, F. Vetrone, A. Speghini, Marco Bettinelli. 2002

159 citations recorded by the source corpus.

In this paper we report on the optical spectroscopy and upconversion studies of Ho3+-doped nanocrystalline and bulk Y2O3, as a function of holmium concentration (0.1, 0.5, 1, 2, 5, and 10 mol %). Emission in the blue, green, red, and NIR portions of the spectrum is recorded after 457.9-nm excitation. Red (646 nm) pumping results in blue and green emission through a two-photon excited-state absorption (ESA) upconversion process. NIR (754 nm) pumping results in blue, green, and red emission. Overall luminescence of the nanocrystalline samples under one-photon excitation or 646-nm pumping is severely reduced when compared to that of the bulk sample, or nonexistent in the case of the 754-nm pumping, which is attributed to adsorbed atmospheric carbon dioxide and/or water on the surface of the nanocrystals. A quenching of the green (5F4, 5S2) → 5I8 emission is noted with increasing Ho3+ concentration that is attributed to a cross-relaxation mechanism involving two holmium ions.

Subfields: Ceramics and Composites, Materials Chemistry, Radiation

View Paper: https://www.semanticscholar.org/paper/f949e09b73c9727306f32a395b44156952ae6726