resumo
A series of novel, colorless, and transparent sot-gel derived hybrid materials Ln-DBM-Si covalently grafted with Ln(DBM-OH)(3)center dot 2H(2)O (where DBM-OH = o-hydroxydibenzoylmethane, Ln = Nd, Er, Yb, and Sin) were prepared through the primary beta-diketone ligand DBM-OH. The structures and optical properties of Ln-DBM-Si were studied in detail. The investigation results revealed that the lanthanide complexes were successfully in situ grafted into the corresponding hybrids Ln-DBM-Si. Upon excitation at the maximum absorption of ligands, the resultant materials displayed excellent near-infrared luminescence. Meanwhile, a model for the indirect excitation mechanism was introduced to discuss the ligands-to-Ln(3+) intramolecular energy transfer. Furthermore, the radiative properties of the Nd(3+) ion and the Er(3+) ion in Ln-DBM-Si are evaluated by applying the Judd-Ofelt analysis.
palavras-chave
ORGANIC-INORGANIC HYBRIDS; OPTICAL-TRANSITION PROBABILITY; INTRAMOLECULAR ENERGY-TRANSFER; RARE-EARTH IONS; HIGHLY LUMINESCENT; EUROPIUM COMPLEXES; PHOTOSENSITIZED LUMINESCENCE; 4F-4F TRANSITIONS; CRYSTAL-STRUCTURE; CONTRAST AGENTS
categoria
Chemistry; Science & Technology - Other Topics; Materials Science
autores
Guo, XM; Guo, HD; Fu, LS; Carlos, LD; Ferreira, RAS; Sun, LN; Deng, RP; Zhang, HJ
nossos autores
Lianshe Fu
Investigador Auxiliar
Luís Carlos
Professor Catedráticoagradecimentos
This project is financially supported by the National Natural Science Foundation of China (Grants 20490210, 206301040, and 20602035) and the MOST of China (Grants 2006CB601103, 2006DFA42610). L.S.F. expresses his gratitude to the Fundacao para a Ciencia e a Tecnologia (Portugal) for the financial support of this work.