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http://hdl.handle.net/10773/19385
Title: | Energy-transfer from Gd(III) to Tb(III) in (Gd,Yb,Tb)PO4 nanocrystals |
Author: | Debasu, Mengistie L. Ananias, Duarte Rocha, Joao Malta, Oscar L. Carlos, Luis D. |
Keywords: | ORGANIC-INORGANIC HYBRIDS EMISSION QUANTUM YIELDS VUV-UV EXCITATION THEORETICAL APPROACH PHOTOLUMINESCENT PROPERTIES HYDROTHERMAL SYNTHESIS COORDINATION-COMPOUNDS LUMINESCENCE TB3+ NANOPARTICLES |
Issue Date: | 2013 |
Publisher: | ROYAL SOC CHEMISTRY |
Abstract: | The photoluminescence properties of (Gd,Yb,Tb)PO4 nanocrystals synthesized via a hydrothermal route at 150 degrees C are reported. Energy-transfer from Gd3+ to Tb3+ is witnessed by the detailed analyses of excited-state lifetimes, emission quantum yields, and emission and excitation spectra at room temperature, for Tb3+ concentrations ranging from 0.5 to 5.0 mol%. Absolute-emission quantum yields up to 42% are obtained by exciting within the (6I)7/2-17/2 (Gd3+) manifold at 272 nm. The room temperature emission spectrum is dominated by the D-5(4) -> F-7(5) (Tb3+) transition at 543 nm, with a long decay-time (3.95-6.25 ms) and exhibiting a rise-time component. The D-5(3) -> F-7(6) (Tb3+) rise-time (0.078 ms) and the P-6(7/ 2) -> S-8(7/2) (Gd3+) decay-time (0.103 ms) are of the same order, supporting the Gd3+ to Tb3+ energy-transfer process. A remarkably longer lifetime of 2.29 ms was measured at 11 K for the P-6(7/2) -> S-8(7/2) (Gd3+) emission upon excitation at 272 nm, while the emission spectrum at 11 K is dominated by the P-6(7/2) -> S-8(7/2) transition line, showing that the Gd3+ to Tb3+ energy-transfer process is mainly phonon-assisted with an efficiency of similar to 95% at room temperature. The Gd3+ to Tb3+ energy transfer is governed by the exchange mechanism with rates between 10(2) and 10(3) s(-1), depending on the energy mismatch conditions between the (6I)(7/2) and P-6(7/2) levels of Gd3+ and the Tb3+ I-5(7), F-5(2,3) and H-5(5,6,7) manifolds and the radial overlap integral values. |
Peer review: | yes |
URI: | http://hdl.handle.net/10773/19385 |
DOI: | 10.1039/c3cp52365a |
ISSN: | 1463-9076 |
Publisher Version: | 10.1039/c3cp52365a |
Appears in Collections: | CICECO - Artigos |
Files in This Item:
File | Description | Size | Format | |
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Energy-transfer from Gd(III) to Tb(III) in (GdYbTb)PO4 nanocrystals_10.1039c3cp52365a.pdf | 1.51 MB | Adobe PDF |
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