Feihong Xue

Luminescent properties of a green long persistent phosphor Li 2 MgGeO 4 :Mn 2+

A novel rare-earth ion free phosphor, Mn2+-activated Li2MgGeO4, was prepared by a high temperature solid-state reaction method. The phase structure was identified by XRD. We reported on its photoluminescence and long persistent luminescence properties. The green emission with a broad band centered at 525 nm corresponds to the 4T1(4G)–6A1(6S) transition of the Mn2+ ions. After irradiation by 254 nm UV light, green long persistent luminescence can be observed and last at least 5 h. Thermoluminescence was studied and the long persistent luminescence mechanism was also discussed in detail.

Long afterglow properties of the blue emission from Pr 3+ -activated Sr 5 Ta 4 O 15 phosphor

Abstract In this study, a novel blue emitting long afterglow (LAG) material based on Pr 3+ -doped Sr 5 Ta 4 O 15 was prepared successfully using a conventional solid-state reaction method. The photoluminescence spectra, excited-state decay curve, LAG decay curve, and thermoluminescence glow curve were obtained to investigate the properities of Sr 5 Ta 4 O 15 :Pr 3+ systematically. The blue LAG emission from Pr 3+ was observed after excitation with a 254-nm ultraviolet lamp. The optimal doping concentration of Pr 3+ for the best LAG performance was experimentally determined to be approximately 4 mol%. Based on the experimental results, a possible model was constructed to illustrate the mechanism of LAG in detail.

Reversible white-brown photochromism in a self-activated long-persistent phosphor Mg 2 SnO 4

Recently, considerable attention has been paid to photochromic (PC) materials owing to its great potential application in various fields, such as rewritable copy papers, erasable optical memory media, smartwindows, sensors, photoswitches and so on. Up until now, most of PC materials come from organics. However, we report that a self-activated LAG phosphor possesses PC property based on non-doped Mg2SnO4 synthesized via a traditional solid-state reaction method. The photoluminescence and long afterglow (LAG) properties were investigated. Interestingly, the white surface color can be colored into brown by ultraviolet-light (UV) irradiation. After visible light irradiation or heat-treatment, the colored Mg2SnO4 can be bleached into white again. The reversible white-brown PC properties of Mg2SnO4 were characterized by diffuse reflectance spectra. Based on the observed phenomena and the obtained experimental results, a tentative model was constructed to illustrate the LAG and PC mechanism.