Insight into the preparation and luminescence properties of yellow-green-emitting [(Sr,Ba)3AlO4F–Sr3SiO5]:Ce3+ solid solution phosphors

Abstract

A design principle for the chemical unit cosubstitution of [Al³⁺–F⁻] for [Si⁴⁺–O²⁻] has been adopted to establish the phase relations between isostructural (Sr,Ba)₃SiO₅ and (Sr,Ba)₃AlO₄F, and solid solutions of (1 − x)Sr₃SiO₅–x(Sr,Ba)₃AlO₄F:Ce³⁺ with tunable luminescence properties have been prepared based on the comparative “one-step” and “two-step” methods. The structures and photoluminescence tuning of the (1 − x)Sr₃SiO₅–x(Sr,Ba)₃AlO₄F:Ce³⁺ phosphors were investigated, and it was found that enhanced emission intensities could be obtained using the two-step method with high crystalline quality. The emission peaks of the (1 − x)Sr₃SiO₅–x(Sr,Ba)₃AlO₄F:Ce³⁺ phosphors were blue-shifted from 520 to 490 nm upon increasing the content from x = 0 to x = 1.0, and the corresponding mechanism has been discussed. The results of the temperature-dependent luminescence properties further verified that the formation of a solid solution can improve the thermal stability of the photoluminescence. White light-emitting diode (w-LED) lamps were fabricated based on the as-prepared bluish-yellow emitting phosphors, and commercial red phosphors, combined with 415 nm NUV-emitting InGaN chips. The best packaged w-LED lamp gave CIE chromaticity coordinates of (0.38, 0.42) with a warm color temperature of 4277 K and a color rendering index of 86.3.