Fabrication And Luminescence Properties Of Ions Of Rare-earth Activated Ba₃La₆?SiO₄?₆ And K₂MgSiO₄ Fluorescent Material

In this paper, some novel fluorescent materials were synthesized by high temperate solid-state method with four kinds of trivalent rare earth ion Eu³⁺, Tb³⁺, and Sm³⁺ as the main activator, and Ba₃La₆?SiO₄?₆ and K₂MgSiO₄ as the main host. We studied their luminescent properties and the specific contents as follows:?1? The red phosphor Ba₃La₆?SiO₄?₆:Eu³⁺ was synthesized by high temperature solid state reaction and its luminescent characteristics were also investigated. The X-ray diffraction patterns indicated that the sample is a pure phase of Ba₃La₆?SiO₄?₆:Eu³⁺. The excitation spectrum includes a series of wide bands and the peaks which locate at 300 nm, 364 nm, 384 nm, 395 nm, 416 nm and 466 nm, and its main peak located at 395 nm. The phosphor exhibits intense emission at 619 nm?⁵D₀?⁷F₂? under 395 nm excitation. The effect of the doping concentration of Eu³⁺ was investigated. The result shows that the luminescent intensity first increases and then decreases with increasing of Eu³⁺ concentration, and reaches the maximal value at 13% in mole. The mechanism of concentration quenching was dipole-dipole interaction. The effect of the doping concentration and chromaticity coordinates of Bi³⁺ was investigated. The results reveal that Bi³⁺ can efficiently transfer excitation energy to Eu³⁺.?2? The green phosphor Ba₃La₆?SiO₄?₆:Tb³⁺ was synthesized by high temperature solid state reaction. The main emission peaks are located at 494nm?⁵D₄?⁷F₆? ?548nm? ⁵D₄?7F5? ?595nm?⁵D₄?7F4? and 627nm?⁵D₄?7F 3?, corresponding to the transitions of Tb³⁺ ions respectively. The best emission peak is located at 548 nm, which presents the emission of green light. The result shows that the luminescent intensity first increases and then decreases with increasing of Tb³⁺ concentration, and reaches the maximal value at 13% in mole. The mechanism of concentration quenching was q-q interaction. Sample color coordinate position did not change significantly with the amount of change Tb³⁺ doped, the sample fluorescence is located in the green zone.?3? The red phosphor Ba₃La₆?SiO₄?₆:Sm³⁺ was synthesized by high temperature solid state reaction and its luminescent characteristics were also investigated. The X-ray diffraction patterns indicated that the sample is a pure phase of Ba₃La₆?SiO₄?₆:Sm³⁺. Sample excitation spectrum is mainly composed of two parts: Between 200 nm to 300 nm is the harge transfer band, and the peak at 240 nm; A series of linear peak between 300 nm to 500 nm is characteristic excitation peak of Sm³⁺, which the strongest peak at 407 nm. The phosphor exhibits intense emission at 605 nm under 407 nm excitation. The result shows that the luminescent intensity first increases and then decreases with increasing of Sm³⁺ concentration, and reaches the maximal value at 3%. The mechanism of concentration quenching was dipole-dipole interaction.?4? The red phosphor K₂MgSiO₄:Eu³⁺ which could be effectively excited by ultraviolet and blue light was synthesized by high temperature solid state reaction, and its luminescent characteristics were also investigated. The principal crystalline phase of the samples is K₂MgSiO₄. The excitation spectra of the sample consist of O2-?Eu³⁺ charge transitions?200³50 nm? and Eu³⁺ ion excitation peak?350⁵00 nm?. The maximum peak appears at 396 nm and the second peak appears at 466 nm. The phosphor presents several emission peaks under 396 nm and 466 nm excitation, which correspond to the ⁵D₀?7FJ? J = 0, 1, 2, 3, 4? transition of Eu³⁺, respectively, and the strongest emission is located at 619 nm. The luminescent intensity increases with the increasing of Eu³⁺ content. The concentration quenching does not occur. The CIE coordinates of K₂MgSiO₄:Eu³⁺ are very close to the NTSC standard. The temperature quenching occurs with increasing temperature, no emission peak red-shift. Fluorescence lifetime of this sample was about 0.535 08 ms.