resumo
Cubic Gd2O3:Eu3+ (0.30, 1.01, 2.78, and 4.60 mol %) nanorods with an average diameter of ca. 14 nm were synthesized at ambient pressure and mild temperature (70 degrees C), using a simple and cost-effective wet-chemical route. The emission-decay curves of the D-5(1) and D-5(0) levels, hereafter referred to as D-5(1) (C-2) and D-5(0)(C-2), were investigated. Although the decay time of the D-5(0) level of the Eu3+ ions residing in the C-2 site of cubic Gd2O3:Eu3+ nanostructures were previously reported, little is known about the rise time component in the D-5(0) emission-decay curve and the energy-transfer pathways responsible for it. The D-5(0)(C-2) rise time and the D-5(1)(C-2) decay time exhibit similar and strong dependence on the Eu3+ concentration and temperature. The D-5(1)(C-2) decay time matches well the rise time extracted from the rising component of the D-5(0)(C-2) emission-decay curve. The decay time of the D-5(0)(C-2) level (ranging from 1.4 to 2.1 ms, depending on the filing factor of the nanorods) is longer than that of the bulk counterpart mainly due to the reduction in the size of the nanorods, which introduces an effective-refractive index smaller than the refractive index of Gd2O3.
palavras-chave
GADOLINIUM OXIDE NANOPARTICLES; LUMINESCENT PROPERTIES; RADIATIVE LIFETIME; EXCITED STATES; NANOCRYSTALS; IONS; EU3+; RELAXATION; LATTICE; SITES
categoria
Chemistry; Science & Technology - Other Topics; Materials Science
autores
Debasu, ML; Ananias, D; Macedo, AG; Rocha, J; Carlos, LD
nossos autores
Duarte Ananias
Investigador Auxiliar
João Rocha
Prof. Catedrático
Luís Carlos
Professor Catedrático
Mengistie Leweyehu Debasu
Investigadoragradecimentos
We thank FCT for the financial support (Grant Reference SFRH/BD/67108/2009) and RNME-Pole University of Aveiro-FCT Project REDE/1509/RME/2005 for the access of STEM and TEM images. The help of RAS Ferreira (University of Aveiro, CICECO) in the time-resolved experiments is gratefully acknowledged.