Sn4+ induced Bi3+ multi-lattice selective occupation and its color-tunable emission of La2MgZrO6: Bi3+, Sn4+ double perovskite phosphors

Abstract

The blue-green emitting La2MgZr1-xSnxO6: 0.02Bi3+ (x = 0–1, abbreviated as LMZ: Bi3+, xSn4+) phosphors with a double-perovskite structure were prepared through a conventional high-temperature solid-state method. A complex ionic substitution phenomenon of selective occupation of Bi3+ in the host of LMZ was observed with Sn4+ doping which was explained on the basis of Rietveld refinement, density functional theory (DFT) calculation and UV–vis spectroscopy results. Fluorescence spectrum analysis showed that LMZ: 0.02Bi3+ emitted a broad green light band with a range of 375–650 nm. With the increase of the Sn4+ concentration replacing Zr4+, the intensity of green light was firstly enhanced and then gradually decreases until disappeared. The emission peak of blue light appears near 400 nm and then its intensity gradually increased. Through Gaussian deconvolution and fluorescence decay curve, it was found that there were two luminescence centers in LMZ: 0.02Bi3+, and three luminescence centers in LMZ: 0.02Bi3+,0.6Sn4+, respectively, which were determined by the Van Uitert empirical formula combined with the energy level splitting theory. The above results demonstrate that how to tune emission color by the substitution of B-site in double perovskite phosphors, which is attractive for future applications.