Study On Long Afterglow Properties Of Mn²⁺ Doped Germanate And Silicate Phosphors

The long afterglow luminescent material is a special kind of photoluminescent material,which can store energy by absorbing the light source and continue to emit light after the excitation.So far,long afterglow materials have been used in diverse territory such as road traffic signs,interior decoration,and medical detection.A variety of matrix material systems have emerged in the research direction.In order to study long afterglow materials that meet the needs of more practical applications,In this paper,germanates and silicates with stable physical and chemical structures and excellent properties were selected as host materials.By introducing transition metal ions Mn²⁺as luminescent centers,New high-efficiency red and green long-persistence materials were synthesized and their unique luminescent and afterglow performance were studied.This paper mainly carries out the following related work:（1）The CaZn Ge₂O₆:Mn²⁺,Bi³⁺red long afterglow luminescent material was successfully developed by traditional and efficient high-temperature solid-phase reaction method.The co-doping of Bi³⁺causes a certain lattice expansion of CaZn Ge₂O₆:Mn²⁺,which also increases the calculated lattice constant and cell volume of the samples under different concentrations.It is found that the introduction of Bi³⁺ions can not only enhance the luminescence properties of Mn²⁺,but also adjust the luminescence color through the measured luminescence spectra and CIE coordinates.Under the excitation of 255 nm ultraviolet light,the CaZn Ge₂O₆ sample with a concentration of 0.25%Mn²⁺and 0.2%Bi³⁺co-doped exhibits the excellent red afterglow performance,and can be observed with the eye in a dark environment for about 1.5h,and the thermoluminescence curve was discussed theoretically.The trap distribution in the germanate afterglow material is analyzed,and the trap depth E was obtained.The energy transfer process between metal ions and the mechanism of afterglow are explained accordingly.（2）The Mn²⁺,Pr³⁺co-doped silicate green long afterglow phosphor was successfully developed by the high temperature solid-phase reaction method,and its crystal structure was analyzed.The unit cell parameters and volume were calculated.The unique spectral characteristics of Ca₂Zn Si₂O₇ phosphors under Mn²⁺single doping and Mn²⁺,Pr³⁺co-doping have been studied.The Ca₂Zn Si₂O₇:Mn²⁺sample exhibits green emission peaking at 520 nm under excitation at 260 nm.The introduction of Pr³⁺greatly enhances its emission intensity.Through the analysis of afterglow attenuation curve and thermoluminescence spectrum,it is found that Pr³⁺co-doping can prolong the afterglow time and enhance the green afterglow brightness of Ca₂Zn Si₂O₇:Mn²⁺,thus improving the afterglow performance.In the process of exploring energy transfer,the mechanism model of afterglow is explained.The work of this paper contributes to a more thorough understanding of the structure and luminescent properties of Mn²⁺doped long afterglow host,and provides a meaningful reference value on the road of exploring new long afterglow luminescent materials.