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Novel broadband luminescence phosphors Ca2−xNaMg2V3O12:xEu3+ have been successfully prepared via the conventional high-temperature solid-state reaction. The effects of concentrations of doped Eu3+ and introducing Li+, K+ on the luminescent properties of phosphor were studied. X-ray diffraction, GSAS structural refinement and photoluminescence spectra were used to characterize the samples. The refinement data ensured where the doped Eu3+ ions occupied the lattice site in the host. Under 355 nm excitation, the emission peak of Ca2NaMg2V3O12:Eu3+ phosphors are located at 610 nm (red) ascribed to the electric dipole transition of Eu3+ from 5D0 → 7F2. In the range of 400–575 nm, Ca2NaMg2V3O12:Eu3+ phosphors have broad emission bands attributed to charge transfer of $${\text{VO}}_4^{3 - }$$ group. Energy transfer mechanism, energy transfer efficiency and critical distance (Rc) of $${\text{VO}}_4^{3 - }$$ → Eu3+ would be analyzed. The emitting color of Ca2NaMg2V3O12:Eu3+ could be tunable from blue-green to near white light.

A novel series of color-tunable single-phased phosphors La1–x–yPO4:xEu3+/yTb3+(x=0, 0.01, 0.02, 0.03, 0.04, 0.05; y=0, 0.05, 0.10, 0.15, 0.20) was synthesized via co-precipitation method with diammonium hydrogen phosphate as precipitant. The morphology, crystal structure and photoluminescence properties of the as-prepared samples were characterized by means of X-ray diffraction(XRD), scanning electron microscopy(SEM) and fluorescence spectrophotometer. The results reveal that the as-synthesized samples calcined at 1100 °C display spherical morphology with uniform distribution. Upon excitation with 350 nm ultraviolet radiation, the LaPO4:Eu3+/Tb3+ phosphors showed a green light peaking at 543 nm assigned to the characteristic 5D4-7F5 emission of Tb3+ and a red light peaking at 591 nm corresponding to the characteristic 5D0-7F1 emission of Eu3+ simultaneously. For the Eu3+/Tb3+ co-activated phosphors, Tb3+ acts as an efficient sensitizer to enhance the emission intensity of Eu3+ ions. The energy transfer mechanism and the emission color tunability of LaPO4:Eu3+/Tb3+ have been studied. The results indicate that a color-tunable luminescence(from green to white to red) can be achieved by adjusting the Eu3+/Tb3+ doping ratio in the LaPO4 host matrix.

Nanosized Ce 3+ and Tb 3+ co-doped LaPO 4 phosphors were synthesized by a mixed co-precipitation method using oxalic acid (H 2 C 2 O 4 ·2H 2 O) and ammonium dibasic phosphate ((NH 4 ) 2 HPO 4 ) as the precipitants. The morphology, crystal structure and photoluminescence properties of the synthesized LaPO 4 :Ce 3+ ,Tb 3+ phosphors were investigated by thermo-gravimetry and differential scanning colorimetry, X-ray diffraction, scanning electron microscope, and photoluminescence emission spectra methods. The results showed that the pure phase of lanthanum orthophosphate can be formed with a lower calcining temperature compared to that of the traditional solid-state reaction method. LaPO 4 phosphors doped with 20 mol% Tb 3+ and 40 mol% Ce 3+ , which were calcined at 900 °C for 1 h, reached the maximum emission intensity under 265 nm excitation. The most prominent emission was at 543 nm, which corresponded to the 5 D 4 → 7 F 5 transition of Tb 3+ ions.

Nanosized green phosphor LaPO 4: Ce 3+, Tb 3+ has been synthesized by microwave-assisted co-precipitation method. The morphology, crystal structure and photoluminescence properties have been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and fluorescence spectrophotometer. The lanthanum phosphate phosphors with monoclinic crystal structure and fine crystallinity and dispersibility were synthesized at 900°C for 1 h and the particle size of the phosphors is ∼ 100 nm. The strongest photoluminescence emission peak is located at 543 nm due to the (5D4→7F5) transition of Tb 3+ ion. The experimental results indicate that nanosized green phosphor 40% Ce 3+ and 20% Tb 3+ doped LaPO 4 synthesized by microwave-assisted co-precipitation method is a beneficial phosphor for high resolution display devices.