The Sr(La1-xTbx)AlO4 (x= 0–1) type layered perovskite: Full substitution of La site, restrained photoluminescence concentration quenching, and novel long afterglow luminescence

Abstract

A series of Tb3+ substituted layered perovskite Sr(La1-xTbx)AlO4 (x = 0–1) was synthesized via solid-state reaction. The influence of Tb3+ on the phase, structure, photoluminescence, and long afterglow properties of the SrLaAlO4 product was investigated. The fully substituted product SrTbAlO4 was found to be isostructural with its SrLaAlO4 counterpart, and the crystal structure parameters were first reported in this work. Photoluminescence investigation found that benefiting from the unique layered crystal structure, the activator Tb3+ was well separated and the optimal doping concentration was found to be as high as 20 at%. Except for photoluminescence, the products simultaneously show long afterglow properties due to disorder cations distribution in the local structure and thus induced defect condition. When the UV light source is turned off, the afterglow luminescence of SrLaAlO4: 0.03 Tb3+ can last over 1 h. The trap distribution of SrLaAlO4: Tb3+ was analyzed in detail by thermoluminescence. The trap depth is calculated to be around 0.7–0.81 eV, the value of which highly coincides with the ideal energy level for trapping and releasing electrons at room temperature. On the basis of the experimental results, the mechanism of long afterglow luminescence of SrLaAlO4: Tb3+ is elaborated and discussed.