Energy Transfer Study on Tb3+/Eu3+ Co-Activated Sol-Gel Glass-Ceramic Materials Containing MF3 (M = Y, La) Nanocrystals for NUV Optoelectronic Devices

Abstract

In the present work, the Tb3+/Eu3+ co-activated sol-gel glass-ceramic materials (GCs) containing MF3 (M = Y, La) nanocrystals were fabricated during controlled heat-treatment of silicate xerogels at 350 °C. The studies of Tb3+ → Eu3+ energy transfer process (ET) were performed by excitation and emission spectra along with luminescence decay analysis. The co-activated xerogels and GCs exhibit multicolor emission originated from 4fn–4fn optical transitions of Tb3+ (5D4 → 7FJ, J = 6–3) as well as Eu3+ ions (5D0 → 7FJ, J = 0–4). Based on recorded decay curves, it was found that there is a significant prolongation in luminescence lifetimes of the 5D4 (Tb3+) and the 5D0 (Eu3+) levels after the controlled heat-treatment of xerogels. Moreover, for both types of prepared GCs, an increase in ET efficiency was also observed (from ηET ≈ 16% for xerogels up to ηET = 37.3% for SiO2-YF3 GCs and ηET = 60.8% for SiO2-LaF3 GCs). The changes in photoluminescence behavior of rare-earth (RE3+) dopants clearly evidenced their partial segregation inside low-phonon energy fluoride environment. The obtained results suggest that prepared SiO2-MF3:Tb3+, Eu3+ GC materials could be considered for use as optical elements in RGB-lighting optoelectronic devices operating under near-ultraviolet (NUV) excitation.

Electrodeposition and Characterization of Lanthanide Elements on Carbon Sheets

“…Eu element with two oxidation states of 2+ and 3+ was selected because Eu(III) ion only exhibits unique 5 D 0 → 7 F 0,1,2,3,4 transitions between 550 and 750 nm. In addition, when the 5 D 0 → 7 F 2 transition is strong, the material with Eu(III) ion exhibits a red color [20,37,45]. On the other hand, Eu(II) ion exhibits a blue color around 400 nm under UV light excitation [20,37].…”

Electrochemical Recovery and Behaviors of Rare Earth (La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, and Yb) Ions on Ni Sheets

“…To further confirm the oxidation state of Eu elements, photoluminescence spectroscopy was employed for the Eu electrodeposited sample because Eu(III) ion has unique 5 D 0 → 7 F 0,1,2,3,4 transitions in the visible region between 550 and 720 nm [ 37 , 38 , 39 , 40 ], while Eu(II) shows no visible light emission under an excitation of UV light. Figure 7 shows excitation and emission spectra for a thick electrodeposited Eu sample and the corresponding 2D- and 3D-PL contour mapping images.…”

“…The PL intensity of the direct transition to an Eu(III) excited energy level was found to be stronger than that of the indirect transition. Several PL peak positions were commonly observed at 578, 590, 613, 647, and 698 nm, commonly associated to the 5 D 0 → 7 F 0 , 5 D 0 → 7 F 1 , 5 D 0 → 7 F 2 , 5 D 0 → 7 F 3 , and 5 D 0 → 7 F 4 , transitions, respectively [ 37 , 38 , 39 , 40 ]. The 5 D 0 → 7 F 2 transition was observed to be the most intense.…”

Electrochemistry, Electrodeposition, and Photoluminescence of Eu (III)/Lanthanides (III) on Terpyridine-Functionalized Ti Nanospikes

“…It was quite interesting that the electrodeposited Eu, Eu + Gd, and Eu + Tb samples showed strong emission signals, while other PL emission signals were very weak. Several sharp peaks were observed and attributed to the 5 D 0 → 7 F J transitions [25,38]; 5 D 0 → 7 F 0 (578.5 nm), 5 D 0 → 7 F 1 (587.2 nm, 594.6 nm), 5 D 0 → 7 F 2 (612.6 nm, 615.4 nm, 619.2 nm, and 623.1 nm), 5 D 0 → 7 F 3 (649.3 nm and 653.6 nm), and 5 D 0 → 7 F 4 (686.8 nm, 691.9 nm, 699.4 nm, and 703.4 nm). Several peaks for each 5 D 0 → 7 F J transition were attributed to the 2J+1 sublevel splittings under crystal field potential.…”