Preparation,Luminescent Properties And Application Of Europium Ions Doped Oxides Phosphors

In the first part of this dissertation,we systematically introduced the history,rescent research progress and future application prospects of long persistent luminescence phosphors,photostimulated luminescence materials,photochromic materials and fluorescence temperature sensing materials.The phase structure of the synthesized samples was investigated by XRD.The luminescence properties of the materials were characterized by steady and transient-state fluorescence spectra,diffuse reflection spectra,fluorescence lifetime,afterglow decay curves and thermoluminescence curves.The applications of the materials prepared in the related aspects were explored.The main research contents in this dissertation are summarized as follows:（1）The Eu³⁺doped Sr₃Sn₂O₇ red phosphors were successfully prepared via high temperature solid phase reaction method.Concentration quenching and thermal quenching of the red phosphors were discussed in detail.Besides,the materials shows photochromism that the surface color of the obtained samples changes reversibly between white and brown by the UV and visible/heating treatment.In addition,a series of Eu³⁺doped Sr₃SnMO₇（M=Sn,Si,Ge,Ti,Zr and Hf）red phosphors were prepared,which exhibited both photochromism and luminescence modulated properties.Based on photochromism and red luminescence,the red emission could be effectively modulated.Most importantly,the Eu³⁺red emission could be reversibly modulated by alternating UV and visible light/thermal treatment with excellent reproducibility,which can be used as non-destructive optical information write-in and read-out.The luminescence modulated of Sr₃SnMO₇:Eu³⁺phosphors based on photochromism indicates that it is expected to be a candidate for optical information storage.Finally,based on the experimental results,a non-radiative energy transfer model from the luminescent centers to the color center was proposed.（2）A novel green super-long persistent luminescence material Ba₂SiO₄:Eu²⁺,Ho³⁺was successfully prepared.After 24 h of UV light removal,the persistent luminescence intensity can still maintain 2.97 mcd m^-2.The outstanding persistent luminescence property is mainly derived from the trap distribution tailoring by Ho³⁺.After the removal of UV light for 15days,green luminescence by 980 nm stimulation was observed.The continuous trap distribution,trap distribution modulation and dynamics of electrons motion in the host were revealed through thermoluminescence measurements under different conditions（such as excitation duration,decay duration and excitation temperature）.The fabricated Ba₂SiO₄:Eu²⁺,Ho³⁺flexible phosphor film allows the optical information write-in after by UV light irradiation and then the stored information read-out by thermal stimulation or 980 nm photostimulation,which gives great application prospect in the optical information storage.（3）An adaptable steady/transient-state fluorescence dual-mode optical thermometry platform LiTaO₃:Ti⁴⁺,Eu³⁺@PDMS was successfully prepared.Based on the fluorescence intensity ratio technology,the proportional fluorescence thermometer exhibits outstanding temperature sensitivity and excellent reversibility in the temperature range of 303-443 K.The maximum S_a and S_r are determined to be 0.671 and 5.425%K^-1,respectively,with minimal temperature resolution of 0.14 K in the whole detecting temperature range.Based on the dependence of Ti⁴⁺fluorescence lifetime on temperature,the maximum S_a and S_r are determined to be 0.122 and 3.637%K^-1,respectively,with minimal temperature resolution of0.027 K.Compared with previously reported proportional fluorescence thermometer,the as-obtained thermometer exhibits much higher temperature sensitivity and temperature resolution.Finally,we prepared flexible 3D micro-rod arrays with handily encrypted information,decrypting the“locked”information by exploiting light,temperature and time-domains.This technology can be applied to the unclonable multi-modal/multi-dimensional anti-counterfeiting field.These results indicate that the material is expected to be used for highly sensitive fluorescence temperature sensing and high-level secure anti-counterfeiting.