Energy-transfer from Gd(III) to Tb(III) in (Gd,Yb,Tb)PO4 nanocrystals

The photoluminescence properties of (Gd,Yb,Tb)PO4 nanocrystals synthesized via a hydrothermal route at 150 °C are reported. Energy-transfer from Gd(3+) to Tb(3+) is witnessed by the detailed analyses of excited-state lifetimes, emission quantum yields, and emission and excitation spectra at room tem...

Full description

Saved in:
Bibliographic Details
Published in:Physical chemistry chemical physics : PCCP 2013-10, Vol.15 (37), p.15565-15571
Main Authors: DEBASU, Mengistie L, ANANIAS, Duarte, ROCHA, João, MALTA, Oscar L, CARLOS, Luís D
Format: Article
Language:English
Subjects:
Chemistry
Energy Transfer
Exact sciences and technology
Gadolinium - chemistry
General and physical chemistry
Luminescent Agents - chemistry
Nanoparticles - chemistry
Nanoparticles - ultrastructure
Phosphates - chemistry
Terbium - chemistry
Ytterbium - chemistry
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:The photoluminescence properties of (Gd,Yb,Tb)PO4 nanocrystals synthesized via a hydrothermal route at 150 °C are reported. Energy-transfer from Gd(3+) to Tb(3+) is witnessed by the detailed analyses of excited-state lifetimes, emission quantum yields, and emission and excitation spectra at room temperature, for Tb(3+) concentrations ranging from 0.5 to 5.0 mol%. Absolute-emission quantum yields up to 42% are obtained by exciting within the (6)I7/2-17/2 (Gd(3+)) manifold at 272 nm. The room temperature emission spectrum is dominated by the (5)D4 → (7)F5 (Tb(3+)) transition at 543 nm, with a long decay-time (3.95-6.25 ms) and exhibiting a rise-time component. The (5)D3 → (7)F6 (Tb(3+)) rise-time (0.078 ms) and the (6)P7/2 → (8)S7/2 (Gd(3+)) decay-time (0.103 ms) are of the same order, supporting the Gd(3+) to Tb(3+) energy-transfer process. A remarkably longer lifetime of 2.29 ms was measured at 11 K for the (6)P7/2 → (8)S7/2 (Gd(3+)) emission upon excitation at 272 nm, while the emission spectrum at 11 K is dominated by the (6)P7/2 → (8)S7/2 transition line, showing that the Gd(3+) to Tb(3+) energy-transfer process is mainly phonon-assisted with an efficiency of ~95% at room temperature. The Gd(3+) to Tb(3+) 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 (6)I7/2 and (6)P7/2 levels of Gd(3+) and the Tb(3+ 5)I7, (5)F2,3 and (5)H5,6,7 manifolds and the radial overlap integral values.
ISSN:1463-9076
1463-9084
DOI:10.1039/c3cp52365a