Photoluminescence and Raman studies of Sm3+ and Nd3+ ions in zirconia matrices: Example of energy transfer and host-guest interactions

Photoluminescence and Raman studies on Sm3+- and Nd 3+-doped zirconia are reported. The Raman studies indicate that the monoclinic (m) phase dominates up to a 10 at.% lanthanide level, while stabilization of the cubic phase is attained at ∼20 and ∼25 at.% of Sm3+ and Nd3+, respectively. Both systems are strongly luminescent under photo-excitation. The emission spectrum at 77 K of the ZrO2:Sm3+ system consists of a broad band at 505 nm, that corresponds to the zirconia matrix. At room temperature the band maximum blue-shifts to 490 nm. Sharper bands corresponding to f-f transitions within the Sm3+ion are also exhibited in the longer wavelength region of the spectrum. Exclusive excitation of the zirconia matrix provides sensitized emission from the acceptor Sm3+ ion. The excitation profile is dominated by a broad band at 325 nm when monitored either at the zirconia or at one of the Sm3+ emissions. A spectral overlap between the 6H5/2→4G7/2 absorption of the Sm3+ ion with the zirconia emission leads to an efficient energy transfer process in the systems. Multiple facets of the spectral behavior of the Sm3+ or Nd3+ in the zirconia matrices, as well as the effects of compositions on the emission and Raman properties of the materials, and the role of defect centers in photoluminescence and the energy transfer processes are discussed. Published by Elsevier B.V.