Self-Luminescence of Perovskite-Like LaSrGaO4 via Intrinsic Defects and Anomalous Luminescence Analysis of LaSrGaO4:Mn2+

A series of deep red phosphors with perovskite-like oxide LaSrGaO 4 as host are synthesized by a high temperature solid state method, and the luminescence properties and mechanisms have been investigated in detail. LaSrGaO 4 presents self-luminescence at 722 nm, and it is proved that the self-luminescence comes from two kinds of electronic defects and three kinds of vacancy defects, which are anti-occupation defects La Sr •, strontium gap defects Sr i ••, the oxygen interstitial defects O i ″, substitution defects Sr La ′, and strontium vacancy defects V Sr ″ . In addition, when Mn 2+ ions are doped in LaSrGaO 4, interestingly, the shape of the emission spectra of LaSrGaO 4:Mn 2+ is the same as that of LaSrGaO 4, and the emission intensities are enhanced greatly. Luminescence of Mn 2+ ions has been confirmed by doping Mg 2+ into LaSrGaO 4 and measuring the lifetimes of host LaSrGaO 4, LaSrGaO 4:Mg 2+, and LaSrGaO 4:Mn 2+ for comparison. The mechanisms of host self-luminescence and Mn 2+ luminescence are discussed by detecting the luminescence centers with the low temperature spectra, calculating the forbidden bandwidth with the diffuse reflectance spectra, and calculating the trap depths with the thermoluminescence spectra and further depicted by establishing the transition model. LaSrGaO 4:Mn 2+ can emit strong deep red light about 722 nm, so the phosphor will have a good application prospect in the field of plant lighting.