Luminescent Terbium Doped Aluminate Particles: Properties and Surface Modification with Asparagine

• Autor(a) principal: Caiut,José M. A.
• Data de Publicação: 2015
• Outros Autores: Messaddeq,Younes, Dexpert,Hervé, Verelst,Marc, Ribeiro,Sidney J. L., Dexpert-Ghys,Jeannette
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Journal of the Brazilian Chemical Society (Online)
• Texto Completo: http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0103-50532015001202536
• topic: hybrid; spray pyrolysis; alumina; rare earth; terbium luminescence

New luminescent organic-inorganic hybrid particles based on Tb-doped aluminates and asparagine (Asn) surface modifiers were investigated. The Tb3+ doped inorganic core was obtained by spray pyrolysis, at 200 ºC γ-AlOOH (BOE:Tbx%) or at 700 ºC γ-Al2O3 (γTA:Tbx%). The reaction of Asn with boehmite in water disaggregated the sub-micronic boehmite particles to give stable dispersion of surface modified nanoparticles Asn:BOE:Tbx% (x = 1 or 5). Concerning the Asn:γTA:Tbx% system, an Asn film wrapping alumina particles was observed. Photoluminescence spectra exhibited the bands assigned to Tb3+5D4 → 7FJ = 6-3 transitions. A broad absorption band (240 nm) was assigned to the host (aluminate) to ion (Tb3+) energy transfer. Efficient energy transfer was observed when active ions are incorporated in the defect-spinel structure of γTA, whereas it was relatively weak for BOE:Tb where Tb3+ are bonded to the hydroxyls groups at nanocrystals surface. It is noticeable that Asn strengthens the linkage of Tb3+ with the aluminate matrix, enhancing the host to dopant energy transfer.