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

摘要

In the present work, the Tb /Eu co-activated sol-gel glass-ceramic materials (GCs) containing MF (M = Y, La) nanocrystals were fabricated during controlled heat-treatment of silicate xerogels at 350 °C. The studies of Tb → Eu 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 4f –4f optical transitions of Tb ( D → F , J = 6–3) as well as Eu ions ( D → F , J = 0–4). Based on recorded decay curves, it was found that there is a significant prolongation in luminescence lifetimes of the D (Tb ) and the D (Eu ) levels after the controlled heat-treatment of xerogels. Moreover, for both types of prepared GCs, an increase in ET efficiency was also observed (from η ≈ 16% for xerogels up to η = 37.3% for SiO -YF GCs and η = 60.8% for SiO -LaF GCs). The changes in photoluminescence behavior of rare-earth (RE ) dopants clearly evidenced their partial segregation inside low-phonon energy fluoride environment. The obtained results suggest that prepared SiO -MF :Tb , Eu GC materials could be considered for use as optical elements in RGB-lighting optoelectronic devices operating under near-ultraviolet (NUV) excitation.