In this work, we first investigate the relationship between temperature and lattice parameters by means of Rietveld refinement and then demonstrate its impact on the luminescence peak position of Eu2+ in Sr8(Si4O12)­Cl8. It is found that with increases in temperature, lattice expansion takes place without significant distortion of the coordination around Eu2+. As a result, the crystal field splitting of the Eu2+ 5d state decreases. At the same time, with the experimental data of the full width at half-maximum of Eu2+ emission at different temperatures and the infrared spectrum, the effective phonon frequency is evaluated and the main vibration motions are determined using first-principles calculation. Due to the high light yield under X-ray excitation and the excellent thermal stability of luminescence intensity and decay, a further optimized sample Sr7.7Eu0.3(Si4O12)­Cl8 could be a potential scintillation material.

An intense reddish-orange phosphor, Gd2MoO6:Sm3+, was developed by solid state chemistry. The photoluminescence excitation and emission spectra, concentration effect are investigated. The results show an efficient energy transfer from MoO66− group to Sm3+ occurs and Sm3+ ion emits an intense reddish-orange light with high color purity and an excellent reproduction quality of optical properties. These results demonstrate that Sm3+ ion with low 4f–4f absorption efficiency in near ultraviolet region can play a role of activator in narrow reddish-orange emitting phosphor potentially useful in ∼370 nm GaN-based light emitting diode through efficient energy feeding by charge transfer absorption of MoO66− group.

Series of NaLa(PO 3 ) 4 :Tb 3+ /Eu 3+ phosphors were prepared by a hightemperature solid-state reaction technique. Structure refinements were performed based on powder X-ray diffraction (XRD) data. VUV−UV−vis photoluminescence (PL), fluorescence decays, time-resolved emission spectra (TRES), and low-voltage cathodoluminescence (CL) spectra were utilized to investigate the luminescence and energy transfer processes. Under VUV−UV light and low-voltage electron beam excitation, NaLa(PO 3 ) 4 :Tb 3+ and NaLa(PO 3 ) 4 :Eu 3+ exhibit characteristic emissions of Tb 3+ ( 5 D 4 → 7 F J ) and Eu 3+ ( 5 D 0 → 7 F J ), respectively. By adjusting the doping concentration of Eu 3+ ions in NaTb 0.70 La (0.30-x) Eu x (PO 3 ) 4 , tunable emission colors are realized in a large color gamut, in which energy transfer from Tb 3+ to Eu 3+ was observed and discussed in detail. On the basis of the good VUV−vis PL and CL properties, NaLa(PO 3 ) 4 :Tb 3+ /Eu 3+ phosphors might be promising for applications in plasma display panels (PDPs) and field emission displays (FEDs).

The work presents the VUV-UV–vis photoluminescence of Ba3La(PO4)3:Ln3+ (Ln = Tb, Eu) prepared by a high-temperature solid-state reaction route. The excitation and emission spectra, the fluorescence decays, and the time-resolved emission spectra were measured and discussed in detail. The results reveal that Tb3+ can efficiently transfer excitation energy to Eu3+ via its 5d and 4f states and therefore sensitizes Eu3+ emission under VUV-UV excitation, resulting in tunable emission in a large color gamut.

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