Ce³⁺-Sensitized GdPO₄:Tb³⁺ Nanorods: An Investigation on Energy Transfer, Luminescence Switching, and Quantum Yield

Abstract

Herein we report the enhanced green emission from Tb 3+ -doped GdPO 4 nanorods sensitized with Ce 3+ . The increase in the rate of nonradiative transition processes in sensitizer due to efficient energy transfer to activator is realized from steady-state and dynamic luminescence studies. Luminescence quenching due to cross relaxation is least significant up to 20 at. % Ce 3+ and 7 at. % Tb 3+ concentration. The quantum yield of the sample with maximum luminescence, i.e., GdPO 4 :Tb 3+ (5 at. %)/Ce 3+ (7 at. %), is found to be 28%. Also, samples are readily redispersible in water and could be easily incorporated in polymer-based films that show strong green light emission under UV excitation. The luminescence switching (ON and OFF) behavior is examined using alternately an oxidizing agent (KMnO 4 ) and then a reducing agent (ascorbic acid) through a redox reaction (Ce 3+ /Ce 4+ ). Both GdPO 4 :Tb 3+ and GdPO 4 :Tb 3+ / Ce 3+ are observed to be paramagnetic.

Preparation and luminescent properties of GdOF:Ce, Tb nanoparticles and their transparent PMMA nanocomposites

“…Because there is a suitable electronic transitions energy levels between Ce 3+ and Tb 3+ ions, the energy can be absorbed by Ce 3+ ions and transferred to Tb 3+ ions, and the nanoparticles finally emit green light due to the relaxation of 7 D 4 ? 7 F J (J = 6-3) transitions in Tb 3+ ions, which has been explained in detail by many researches [9,[27][28][29][30][31][32]. As shown in the inset of Fig.…”

Synthesis of $$\hbox {Tb}^{3+ }$$ Tb 3 + ion doped $$\hbox {ZnWO}_{4}$$ ZnWO 4 phosphors and investigation of their photoluminescence properties: concentration effect

“…It is revealed from figure 5a that the strongest intensity is observed upon excitation at 270 nm; this result further supported the effective energy transfer from the host lattice to the Tb 3+ ions. The spectra consist of emission peaks originating from the 5 D 3 and 5 D 4 energy states with little background emission from the host lattice; the peaks observed in the range between 400 and 467 nm originate from the 5 D 3 state and can be ascribed to the 5 D 3 -7 F 5 (423 nm), 5 D 3 -7 F 4 (437 nm), 5 D 3 -7 F 3 (45 nm) and 5 D 3 -7 F 2 (467 nm) transitions whereas the peaks centred at 489, 544, 585 and 621 nm originate from the 5 D 4 state and they can be attributed to the 5 D 4 -7 F 6 , 5 D 4 -7 F 5 , 5 D 4 -7 F 4 and 5 D 4 -7 F 3 transitions, respectively [16,31,32]. Figure 5b shows the emission spectra of ZnWO 4 :xTb 3+ (x = 1, 3, 5, 7, 10 and 12 at%) obtained by monitoring the excitation wavelength at 270 nm, this wavelength was chosen because the strongest emission was observed upon excitation at this wavelength.…”

Room-temperature synthesis and photoluminescence of hexagonal CePO4 nanorods

“…Rare earth phosphate nanomaterials have been extensively reported due to their high-performance photoluminescence [1,2]. Especially, pure and rare-earth ion doped CePO 4 nanomaterials have received a lot of research interest [3][4][5][6].…”