@article{eac33fa3c592460f9ab3ab7131eef271,
title = "X-ray luminescence of LaF3: Tb3+ and LaF3: Ce3+, Tb3+ water-soluble nanoparticles",
abstract = "We report x-ray luminescence from La F3: Ce3+, Tb3+ and La F3: Tb3+ water-soluble nanoparticles. The x-ray luminescence is dominated by emission from Tb3+ ions, similar to photoluminescence spectra of the nanoparticle aqueous solutions and spectra from nanoparticle powders precipitated from the aqueous samples. Coating the nanoparticles with an insulating inorganic La F3 or organic H2 N- (C H2)10 -COOH layer can enhance the x-ray luminescence from the aqueous nanoparticles. This enhancement is most likely due to the decreased energy loss due to the particle-solvent interactions.",
author = "Yuanfang Liu and Wei Chen and Shaopeng Wang and Joly, {Alan G.} and Sarah Westcott and Woo, {Boon Kuan}",
note = "Funding Information: Financial support from the U.S. Army Medical Research Acquisition Activity (USAMRAA) under Contract No. W81XWH-05-C-0101 is acknowledged. W.C. would like to thank the Startup and LERR Funds from UTA and the support from the NSF and DHS joint program (CBET-0736172). Part of the research described was performed at the W.R. Wiley Environmental Molecular Sciences Laboratory, a National Scientific User Facility sponsored by the Department of Energy{\textquoteright}s Office of Biological and Environmental Research and located at the Pacific Northwest National Laboratory (PNNL). PNNL is operated by Battelle for the U.S. Department of Energy under Contract No. DE-AC06-76RLO1830. We thank Dr. Paul Weckler for help on the x-ray measurements at the Biosystems & Agricultural Engineering Department, Oklahoma State University. Table I. Luminescence lifetimes. Luminescence lifetime(ms) Wavelength(nm) 489 542 584 621 0.035 M La F 3 : Ce Tb 4.6 4.7 4.0 3.9 0.035 M La F 3 : Tb 3.3 3.3 3.3 3.4 Powder La F 3 : Ce Tb 3.1 3.8 3.6 3.6 Powder La F 3 : Tb 1.1 1.3 1.2 1.2 0.04 M La F 3 : Tb ∕ A A 11 3.2 3.8 3.6 3.6 0.04 M La F 3 : Tb ∕ La F 3 3.2 3.5 3.3 3.3 FIG. 1. An x-ray powder diffraction spectrum of La F 3 : Tb nanoparticles. FIG. 2. TEM images of nanoparticles (A) La F 3 : Ce , Tb ; (B) La F 3 : Tb ; (C) La F 3 : Tb ∕ La F 3 ; and (D) La F 3 : Tb ∕ A A 11 . The inserts display high resolution TEM images of the corresponding nanoparticles. Scale bar, 100 nm ; scale bar for inserts, 5 nm . FIG. 3. PL spectra of La F 3 : Ce , Tb nanoparticles aqueous solutions [(a) and (b)] and solid powder sample (c) with excitation wavelength at 260 nm . FIG. 4. PL spectra of (A) 0.035M La F 3 : Tb and (B) solid La F 3 : Tb with excitation wavelength at 260 nm . FIG. 5. X-ray excited luminescence of (a) La F 3 : Ce , Tb suspensions with different concentrations; (b) La F 3 : Tb nanoparticles with different concentrations. FIG. 6. X-ray excited luminescence of 0.4 M and 0.08 M aqueous solutions of as-synthesized La F 3 : Tb nanoparticles with organic stabilizer [ A A 11 : H 2 N – ( C H 2 ) 10 – C O O H ], and La F 3 : Tb ∕ La F 3 core∕shell nanoparticles. FIG. 7. Luminescence lifetimes recorded at 488 nm following 260 nm excitation of 0.035 M La F 3 : Ce , Tb (upper), 0.04 M La F 3 : Tb ∕ La F 3 (middle), and 0.035 M La F 3 : Tb (lower). ",
year = "2008",
doi = "10.1063/1.2890148",
language = "English (US)",
volume = "103",
journal = "Journal of Applied Physics",
issn = "0021-8979",
publisher = "American Institute of Physics Publising LLC",
number = "6",
}