Synthesis of a Broad-Band Excited and Multicolor Tunable Phosphor Gd₂SiO₅:Ce³⁺,Tb³⁺,Eu³⁺for Near-Ultraviolet Light-Emitting Diodes

Abstract

Broad-band near-ultraviolet (NUV)-excited and multicolor-emitting Gd2SiO5:Ce3+,Tb3+,Eu3+ phosphors were synthesized by solid-state reaction. The emission color of the phosphors can be tuned from blue (0.153, 0.091) to green (0.325, 0.495) and eventually to red (0595, 0.370) through efficient Ce3+ → (Tb3+) n → Eu3+ energy transfer. NUV light was strongly absorbed by the Ce3+ ions, and the excited energy was transferred to Tb3+ ions, which produced intense green emission peaks. Finally, the excited energy was transferred from Tb3+ to Eu3+ ions, which is attributed to red emission peaks. These multicolor tunable Gd2SiO5:Ce3+,Tb3+,Eu3+ phosphors are promising materials for applications in NUV light-emitting diodes.

Influence of Cu+ cations on photoluminescence properties of Tb3+ in Cu+–Na+ ion-exchanged sodium-borosilicate glasses

“…In contrast, it is notable that an additional excitation band centered at around 286 nm was observed in the PLE spectrum (λ em = 545 nm) of GTbCu20, compared with GCu20 and GTb samples. The above observation strongly indicates that an energy transfer from Cu + to Tb 3+ cations occurs in GTbCuy (y = 10-40) glasses [2,13]. Interestingly, with increasing IET, the doping content of Cu + is increased, and the additional excitation band of Cu + in GTbCuy shows a red shift from 264 to 286 nm with an energy difference of about 2913 cm −1 .…”

“…The broad band extending from 200 to 260 nm with a maximum at about 233 nm is attributed to the spin-allowed 4f 8 → 4f 7 5d transition of the Tb 3+ cations [1]. Meanwhile, the line-shaped absorption peaks in the range of 285-510 nm are ascribed to the forbidden intra-4f transitions of Tb 3+ [13,27]. The PLE spectrum monitored with 545 nm of GCu20 exhibits almost no absorption in the wavelength range of 200-520 nm.…”

“…4(b) [2,4,13]. The PL spectra (λ ex = 286 nm) and the PLE spectra (λ em = 447, 545 nm) of GCu10 and GTbCu10 samples are illustrated as a reference.…”

“…It is noticed that all the decay curves are in the nonexponential mode. The decay processes of these glass samples are characterized by an average fluorescence lifetime τ avg À Á , which can be estimated by using the following equation [2,13]:…”

“…Thus, it is an interesting work to exploit new sensitizers, which possess strong absorption in the UV wavelength range. Currently, Eu 2+ and Ce 3+ ions with intense parity-allowed 4f 7 → 4f 6 5d 1 transitions in the UV region have been used to sensitize the photoluminescence of RE cations in multi-activators co-doped compounds, such as Sr 3 AlO 4 F:Ce 3+ ,Tb 3+ [12], Sr 3 Y(PO 4 ) 3 :Eu 2+ ,Tb 3+ ,Sm 3+ [7], and Gd 2 SiO 5 :Ce 3+ ,Tb 3+ ,Eu 3+ [13].…”