Spectroscopic Investigation On MgXO₃?X=Ge,Si? Doped With Pr³⁺ Ions

Because of the wide application of rare earth luminescent materials doped trivalent praseodymium ion(Pr³⁺),researches on its properties and preparation methods have become hot and focus.In photoluminescence?PL?emission of Pr³⁺types,there are plenty of reports of sharp-line emission generated by f?f transition,while less studies on broadband emission originated from d?f transition.It is to investigate the relationship between the d?f broadband emission and the electron transfer state in MgGeO₃:Pr³⁺and MgSiO₃:Pr³⁺phosphors in this paper.Moreover,On this basis,long persistent luminescence and up-conversion charging?UCC?produced from electron transfer are supplemented in MgGeO₃:Pr³⁺phosphors.MgGeO₃:Pr³⁺and MgSiO₃:Pr³⁺phosphors with similar chemical formula were prepared by high temperature solid-state reaction method.The d?f broadband emission is shown to exist in MgSiO₃:Pr³⁺phosphors.The results show that the impurity trapping exciton?ITE?can quench the d?f emission by analysis of PL spectrum,thermoluminescence excitation spectrum,and temperature-dependence of emission spectrum in MgGeO₃:Pr³⁺phosphors.Finally,the mechanism of ITE is explained by schematic configuration coordinate.Furtherly,In order to supplement of the luminescent properties of MgGeO₃:Pr³⁺phosphors.The MgGeO₃:Pr³⁺samples were irradiated by ultraviolet?254nm?and blue laser?450nm?respectively.It was found that both ultraviolet and blue laser can produce long persistent luminescence in MgGeO₃:Pr³⁺phosphors which indicates that both wavelengths can fill the electron traps.It is also proved that filling electron traps by450nm blue light is a two-photon process in MgGeO₃:Pr³⁺phosphors by analysis of second-order relationship curve of I-P,i.e.Intensity-Power curve,which is called up-conversion charging.The mechanism of long persistent luminescence and up-conversion charging phenomenon is explained by drawing the schematic diagrams.In this paper,It is discussed that the different emission behaviors and mechanisms in different hosts doped Pr³⁺in detail,and the properties of long persistent luminescence and up-conversion charging are further supplemented in MgGeO₃:Pr³⁺phosphors.The application of luminescent materials doped Pr³⁺has been greatly promoted.