Phosphorescence behavior and photoluminescence mechanism of Dy3+ sensitized β-Zn3(PO4)2: Mn2+ phosphor

Abstract A red long persistent phosphor (LPP) of β-Zn 3 (PO 4 ) 2 : Mn 2+ , Dy 3+ was synthesized conventionally via homogeneous coprecipitation and conventional solid-state sintering methods. The emission peak of phosphor was found at 620 nm, which can be assigned to the 4 T 1g  →  6 A 1g transition of Mn 2+ . The decay curves of phosphors show that Dy 3+ ions co-doping can largely improve the performance of the red LLP of β-Zn 3 (PO 4 ) 2 : Mn 2+ . This red long-persistent luminescence was observed for about 4 h in the limit of light perception for naked eyes when excited under 254 nm UV light for 5 min. Thermoluminescence analysis indicates that the dopant of Dy 3+ ions produced suitable trap depth of defects that enhanced the luminescence of LPP. It is hypothesized that Dy 3+ as a sensitizer transfers its energy to the luminescent center of Mn 2+ . We propose that the emission mechanism of LPP experiences a series process of electron–hole pairs: production, release, movement and combination. The decay time of LPP has close relationship with the life span of electron–hole pairs during their releasing time from traps and moving length on their path.