Raman characterization and photoluminescence properties of La1-xTbxPO4·nH2O and La1-xTbxPO4 phosphor nanorods prepared by microwave-assisted hydrothermal synthesis. Issue 14 (1st October 2017)

• Record Type: Journal Article
• Authors: Colomer, M.T.; Bartolomé, J.; Ortiz, A.L.; de Andrés, A.
• Is Part Of: Ceramics international. Volume 43:Issue 14(2017)
• Page Start: 10840
• Page End: 10847
• Publication Date: 2017-10-01
• Subjects: A. Processing: microwave processing -- C. Properties: optical properties -- E. Applications: functional applications -- Powders: chemical preparation; Ceramics -- Periodicals; Céramique industrielle -- Périodiques; Ceramics; Periodicals; Electronic journals; 666
• DOI: 10.1016/j.ceramint.2017.05.110
• Languages: English
• ISSNs: 0272-8842

Abstract

Abstract: The effect of the Tb 3+ –doping content (in the range 0–100 mol%) on the structure (using Raman spectroscopy) and photoluminescence (PL) properties of both rhabdophane-type La1- x Tb x PO4 · n H2 O and monazite-type La1- x Tb x PO4 single-crystal nanorods was investigated. La1- x Tb x PO4 · n H2 O was directly obtained by microwave-assisted hydrothermal synthesis and La1- x Tb x PO4 by calcination of La1- x Tb x PO4 · n H2 O at 700 °C in air for 2 h. It was found that the characteristic Raman bands shift to higher wavenumbers and become broader with increasing Tb 3+ concentration, which is attributed to attendant unit-cell volume reduction. The PL due to the Tb 3+ f-f transitions has been studied with continuous and pulsed excitations. The PL intensity increases with doping and is maximum for La0.80 Tb0.20 PO4 · n H2 O and La0.85 Tb0.15 PO4, i.e., for rhabdophane and monazite-type structures, respectively. A quenching effect is detected for concentrations below x =0.05, but constant efficiency is obtained at higher doping. The calcination increases the efficiency by a factor around 2 due to the combined effects of water molecules and defect elimination. The PL decay curves reveal a long lifetime attributable to single Tb 3+ ions which is almost independent of doping for monazite nanorods (5–4.5 ms), and a shorter one around 0.2 ms most likely due to Tb 3+ dimmers.