Luminescent Properties and Energy Transfer Mechanism of Gd3+ and Eu2+ Co-doped Phosphate Glasses

Abstract

The phosphate glasses doped with Eu 2? , Gd 3? , respectively, and co-doped with Gd 3? and Eu 2? were prepared by high-temperature melting method. The transmission spectra, the excitation spectra, the emission spectra and the fluorescent decay time were investigated. The energy transfer process between Gd 3? and Eu 2? was studied. From the excitation spectra and the emission spectra of the phosphate glasses doped with Eu 2? , we observed that the emission intensity of Eu 2? shows higher for 0.02 mol% Eu 2? -doped phosphate glass. According to the excitation spectra and the emission spectra and the fluorescence decay curves, when the concentration of Eu 2? was 0.02 mol%, the optimal concentration of Gd 3? was 0.3 mol%. Based on Dexter theory, it is shown that the energy transfer between Gd 3? and Eu 2? was nonradiation energy transfer by analyzing the energy-level diagram. The fluorescence decay curves of Gd 3? were expressed by the Inokuti-Hirayama's model and were used to analyze energy transfer mechanism between Gd 3? and Eu 2? . And the energy transfer efficiency was also calculated.

Associated Aspects on Structure, Morphology and Photoluminescence of MgAl2O4:x% Gd3+ Nanophosphor Prepared via Citrate Sol–Gel Method

“…The peak shift from 385 to 392 nm is certainly attributed to arise from the host since the emission at around 385 -392 nm (violet) is not the characteristic of the Gd 3+ spectroscopy. [37][38][39][40] Therefore, the results suggest that as the Gd 3+ concentration is increased, the defects levels within the host responsible for the 385 nm is slightly modified or shifted a little bit downwards within the Eg. Thus, it is reasonable to conclude that Gd 3+ serves as a very unique foreign candidate into the host crystal structure, which donates the observed emission located at 315 nm.…”

“…23 The emission band at 315 nm is related to transitions of Gd 3+ ion corresponding to the 6 P7/2→ 8 S7/2. [37][38][39][40] . The emission at 628 nm can either be attributed to the 6 G7/2→ 8 P3/2 (Gd 3+ transition) or second order emission of 6 P7/2→ 8 S7/2 (315 nm).…”

Luminescence Properties of Eu2+/Eu3+Activated Barium Aluminate Phosphors with Gd3+Concentration Variation

“…In this way energy sinks in the lattice. 30 The emission spectra of annealed compounds at 1000 o C show the same PL behaviour, however, the intensity of 498 nm band increases three folds for BaAl 2 O 4 :Eu 3+ (1%):Gd 3+ (1%) than that for BaAl 2 O 4 :Eu 3+ (1%). This increase in brightness indicates that the energy absorbed by Gd 3+ ions can be transferred efficiently to Eu 3+ due to some energy matching.…”

“…30 Some other lattices have also been reported which involve energy transfer from Gd 3+ to Eu 2+ . 31,32 Thus increase in brightness by the addition of Gd 3+ ion up to 1 mol% is due to the sensitizing action of Gd 3+ .…”

Synthesis, Structural and Luminescence Studies of Europium Doped Borate Glasses

“…Glasses doped with RE ions are of larger interest due to their use in infrared-to-visible up-converters, solidstate lasers, bulk lasers, waveguide lasers, planar waveguides, temperature sensors, flat panel displays, field emission displays, optical fiber amplifiers, high-density memory devices, high-density frequency domain optical data storage, color display devices and electroluminescent devices [1][2][3]. Among all RE ions, europium is a unique component because of the divalent or trivalent valence state.…”