Title: Room temperature synthesis of β-NaGdF 4 : RE 3+ (RE= Eu, Er) nanocrystallites and their luminescence

Abstract

In this study, a room temperature synthesis was developed for phase pure β-NaGdF₄ nanocrystallites as well as 5, 10, and 20% Eu³⁺ or 5% Er³⁺ doped material. Rare earth acetates and NaCl react in a 1:2 M ratio with a variable excess of NH₄F in ethylene glycol within 24 hours. Since the thermodynamic stability of the hexagonal phase decreases along the lanthanide series, a larger excess of NH₄F was required for the synthesis of luminescent samples doped with the smaller Er³⁺ ions than for Eu³⁺ doped or pure β-NaGdF₄. The materials were characterized by powder X-ray diffraction, electron microscopy, and luminescence spectroscopy. The Eu³⁺-doped samples show ⁵D₀→⁷F_J and ⁵D₁→⁷F_J luminescence after Eu³⁺ excitation at 394 nm or Gd³⁺ excitation at 273 nm and 308 nm. The ratio of ⁵D₁ vs. ⁵D₀ luminescence is influenced by the excitation wavelength and the Eu³⁺ concentration. Lastly, the Er³⁺-doped samples show green and red upconversion luminescence, respectively, from the ²H_11/2+⁴S_3/2→⁴I_15/2 and ⁴F_9/2→⁴I_15/2 transitions after 970 nm excitation.

Authors:

Tessitore, Gabriella; Mudring, Anja-Verena; Kr?mer, Karl W.

Publication Date:

Fri Sep 01 00:00:00 EDT 2017

Research Org.:

Ames Lab., Ames, IA (United States)

Sponsoring Org.:

USDOE; European Union (EU)

OSTI Identifier:

1355356

Report Number(s):

IS-J-9034
Journal ID: ISSN 0022-2313; PII: S0022231316305324

Grant/Contract Number:  

AC02-07CH11358; 316906

Resource Type:

Accepted Manuscript

Journal Name:

Journal of Luminescence

Additional Journal Information:

Journal Volume: 189; Journal Issue: C; Journal ID: ISSN 0022-2313

Publisher:

Elsevier

Country of Publication:

United States

Language:

English

Subject:

36 MATERIALS SCIENCE; β-NaGdF4; Nanoparticles; Room temperature synthesis; Europium; Erbium