Preparation, structure, luminescence properties of terbium doped perovskite-like structure green-emitting phosphors SrLaAlO4:Tb3+

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Rare earth aluminate phosphors are well-known for being nontoxic and environmentally friendly. In this work, Tb3+-doped SrLaAlO4 phosphors were synthesized via a facile high temperature solid-state reaction method. The Optimum reaction temperature is determined to be 1300 °C based on the results of powder X-ray diffraction (XRD). The SEM patterns and TEM images correspond with the results of Rietveld refinement and show that the SrLa1-xAlO4:xTb3+ samples present a flaky structure. The results of photoluminescence spectrums (PL) show that SrLa1-xAlO4:xTb3+ phosphors can absorb in the UV–vis spectral region of 228 nm–263 nm and exhibit several emission peaks between 450 and 650 nm, and the highest peak was at 508 nm. The luminescence properties of SrLa1-xAlO4:xTb3+ have a strict dependence on the cation substitution levels. When the doping concentration of Tb3+ was 0.05, the emission intensity of the sample is strongest. The thermal quenching result of the SrLa0.95AlO4:0.05 Tb3+ phosphors shows that these phosphors are relatively sensitive to temperature changes under an excitation of 228 nm, as the temperature increases from 25 °C to 125 °C, the emission intensity (peak at 548 nm) decayed to 55.11% of that at room temperature. However, when the temperature increases to 125 °C, the emission intensity (peak at 548 nm) decayed to 61.16% of the initial value under an excitation of 263 nm, which showed a relatively good thermal stability. The internal quantum efficiency (QE) values of the SrLa0.95AlO4:0.05 Tb3+ phosphors was measured and determined to be 48%. Under excitations of 228 nm and 263 nm, the lifetimes of the optimized sample SrLa0.95AlO4:0.05 Tb3+ were 1.3986 ms and 1.2095 ms, respectively, and the CIE coordinates of the sample were calculated as (0.2971, 0.4981), (0.3056, 0.5329), respectively. Under both excitations SrLa0.95AlO4:0.05 Tb3+ exhibited high-color-purity green emission.