'Eu POT.3+' photoluminescence enhancement due to thermal energy transfer in 'Eu IND.2''O IND.3'-doped Si'O IND.2'-'B IND.2''O IND.3'-Pb'O IND.2' glasses system

In this work, Eu3+-doped lead borosilicate glasses (SiO2-B2O3-PbO2) synthesized by fusion method had their optical properties investigated as a function of temperature. Atomic Force Microscopy images obtained for a glass matrix annealed at 350 and 500 °C show a precipitated crystalline phase with sizes 11 and 21 nm, respectively. Besides, as the temperature increases from 350 to 300 K a strong Eu3+ photoluminescence (PL) enhancement takes place. This anomalous feature is attributed to the thermally activated carrier transfer process from nanocrystals and charged intrinsic defects states to Eu3+ energy levels. In addition, the PL peaks in this temperature range were assigned to the Eu3+ transitions 5D0→7F2, at 612 nm, 5D0→7F1, at 595 nm, and 5D0→7F0, at 585 nm. It was also observed that the 5D0→7F3 and 5D0→7F4 PL bands at 655 and 700 nm, respectively, show a continuous decrease in intensity as the temperature increases.CAPESMCT/CNPqFAPEMI

Thermoluminescence, structural and magnetic properties of a Li(2)O-B(2)O(3)-Al(2)O(3) glass system doped with LiF and TiO(2)

A Li(2)O-B(2)O(3)-Al(2)O(3) glass system, un-doped and doped with LiF, and/or TiO(2) was synthesized by the fusion method and its physical properties were investigated by thermoluminescence (TL), X-ray diffraction (XRD), electron paramagnetic resonance (EPR), atomic force microscopy (AFM) and differential thermal analysis (DTA). The samples were subjected to gamma-rays from a colbalt-60 ((60)Co) source. These techniques provided evidence of LiF and LiF doped with Ti crystal formation in the glass system. A TL glow peak at about 433 K was sensitive to (60)Co gamma-rays and showed good linearity with doses and consequently could be used to quantify radiation doses. Crown Copyright (C) 2011 Published by Elsevier B.V. All rights reserved.Brazilian agency: CNPqConselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de Minas Gerais (FAPEMIG)Brazilian agency: FAPEMIGCoordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Brazilian agency: CAPE