abstract
Lanthanide (Eu and Nd)-doped hydrocalurnite has been prepared by a coprecipitation method. All samples, with Eu3+ and Nd3+ contents up to 4% (molar ratio), show a single crystallographic phase, without segregation of secondary lanthanide-containing phases. Calcination affords lime and mayenite, with lanthanide cations embedded in the structure. The photoluminescence spectra of the noncalcined samples consist of Eu3+ (in the visible region) and Nd3+ (in the NIR) intra-4f transitions and a broad band ascribed to Al-related defects. The Eu3+5D0 lifetime values and quantum efficiency of the Eu3+/Nd3+ codoped hydrocalumite decrease ca. 10%, relative to the single doped material, suggesting that the Nd3+ incorporation activates nonradiative channels for the D-5(0) depopulation. High-temperature stable ceramic pigments, prepared from Eu3+ and Nd3+ doped hydrocalumite precursors, afford multiwavelength luminescent materials emitting in large vis/NIR spectral region, with potential applications as barcodes and in broadband amplifiers. The emission spectra of the calcined samples give unequivocal attributed to Eu3+ sites in CaO and mayenite. Upon calcination, the absolute emission quantum yield of the Eu3+-doped sample increases from less than 0.01 to 0.06.
keywords
LAYERED DOUBLE HYDROXIDES; ORGANIC-INORGANIC HYBRIDS; ANIONIC CLAYS; HYDROTALCITE; PHOTOLUMINESCENCE; CATALYSTS; OXIDES; CALCINATION; CENTERS; YTTRIUM
subject category
Chemistry; Materials Science
authors
Dominguez, M; Perez-Bernal, ME; Ruano-Casero, RJ; Barriga, C; Rives, V; Ferreira, RAS; Carlos, LD; Rocha, J
our authors
João Rocha
Director
Luís António Ferreira Martins Dias Carlos
Full professor
Maria Rute de Amorim e Sá Ferreira André
Vice Directoracknowledgements
M.E.P.-B., R.J.R.-C., and V.R. acknowledge financial support from MICINN (Grant MAT2009-08526), Junta de Castilla gamma Leon (Grant SA111A09), and ERDF. R.A.S.F., L.D.C., and J.R. thank FCT and FEDER for financial support.