Electronic Transition and Energy Transfer Processes in LaPO₄−Ce³⁺/Tb³⁺ Nanowires

Abstract

Ce3+ and Tb3+ coactivated LaPO4 nanowires and micrometer rods were synthesized by hydrothermal methods. Their fluorescent spectra and dynamics were systematically studied and compared. The results indicated that the extinction coefficients of Ce3+ and Tb3+ in nanowires were higher than those in micrometer rods. The electronic transition rates of Ce3+ and Tb3+ in nanowires had little variation in contrast to those in micrometer rods, and the energy transfer rate and efficiency of Ce3+ --> Tb3+ in nanowires were reduced greatly. It is important to observe that the brightness for the 5D4-7F5 green emissions of Tb3+ via energy transfer of Ce3+ --> Tb3+ in nanowires increased several times that in micrometer rods. This was attributed to the decreased energy loss in the excited states, being higher than 5D4 due to the hindrance of the boundary.

In situ preparation and luminescent properties of LaPO4:Ce3+, Tb3+ nanoparticles and transparent LaPO4:Ce3+, Tb3+/PMMA nanocomposite

“…6b. This indicates that an efficient energy transfer from Ce 3+ to Tb 3+ occurs in La 0.45 Ce 0.45 Tb 0.1 PO 4 nanoparticles, as reported previously [32][33][34][35][36][37][38][39][40]. However, for La 0.45 Ce 0.45 Tb 0.1 PO 4 /PMMA nanocomposite, the excitation spectrum is not well resolved, and only the strongest band around 290 nm of Ce 3+ is present (other shoulders present in that of the La 0.45 Ce 0.45 Tb 0.1 PO 4 nanoparticles cannot be seen clearly here).…”

“…LaPO 4 :Ce 3+ , Tb 3+ is mainly used as a green emitting phosphor for fluorescent lamp due to its high quantum efficiency, thermal stability at high temperature and sharp emission around 543 nm with high intensity [31]. La-PO 4 :Ce 3+ , Tb 3+ nanoparticles have been studied by several groups in recent years and synthesis procedures are well-established [32][33][34][35][36][37][38][39][40]. However, as far as we know, so far no reports have appeared concerning the integration of luminescent LaPO 4 :Ce 3+ , Tb 3+ nanoparticles into PMMA matrix.…”

Energy transfer processes in electrospun LaOCl:Ce/Tb nanofibres

“…Because of the fluorescence quenching effect of higher Ce 3þ concentrations at 10 mol% Tb 3þ ion concentration, the energy transfer from Ce 3þ to Tb 3þ is incomplete in LaOCl:Ce/Tb nanofibres. The fluorescence lifetimes for the 5 D 4 state in LaOCl:Ce/ Tb nanocrystals could be decreased upon increasing the Ce 3þ dopant concentration, similar to the effect seen in LaPO 4 :Ce/Tb nanowires [29,30].…”

Luminescent properties of nano-sized Y2O3:Eu fabricated by co-precipitation method

“…However, in those particles containing few or no traps, Eu 3+ luminescence quenches at high concentration or do not quench at all. Therefore, luminescence quenching occurs at higher concentration in nano-sized materials than in normal ones [17]. In addition, owing to the enlargement of the lattice constant of nanopowders, the phonon density may decrease.…”