Preparation And Property Regulation Of Zn₃?BO₃??PO₄? Phosphor For UV-near UV Light

In the paper,Rare earth ions RE(RE=Ce3+,Tb3+)and transition metal ions(Mn2+)doped phosphors were synthesized by high temperature solid state reaction technique using Zn3(BO3)(PO4)as matrix,and were investigated by XRD,crystal structure,emission excitation spectra,lifetime curves,etc.The luminescence characteristics of the material were analyzed and improved by the methods of cation substitution,energy transfer and defect introduction.The main research contents are as follows:(1)Zn3(BO3)(PO4):Ce3+ fluorescence powder was synthesized by high temperature solid phase method.By observing its emission spectra,it is found that Zn3(BO3)(PO4):Ce3+ has two different emission spectras.The changes between the two peaks should be consistent if it is caused by 5d?4F7/2 and 4F5/2(double ground state)of Ce3+.Therefore the position of Ce3+ should also be the cause of these two peaks.We replace Zn2+ with Mg2+ and Ca2+,respectively.Taking into account their fitting peaks and the crystal structure,we deeply explored the luminescence principle of Zn3(BO3)(PO4):Ce3+ and Zn2-xMx(BO3)(PO4):Ce3+(M=Mg,Ca)and found that the emission spectrum of Ce3+ is come from its 5d energy level jump to double ground statecombine with Ce3+ take three different Zn2+ lattice simultaneously.At the same time,the cationic substitution method is used to make Ce3+ emit a specific position spectrum.(2)A series of Ce3+,Tb3+,Mn2+ doped Zn3(BO3)(PO4)phosphors were synthesized by high temperature solid phase method.In the host Zn3(BO3)(PO4),the emission spectra of Ce3+ coincide with the excitation spectra of Tb3+.By analyzing the life curve changes of Ce3+,Tb3+in Ce3+,Tb3+co-doped Zn3(BO3)(PO4),we found Ce3+ transfer energy to Tb3+.the energy transfer efficiency of Ce3+ to Tb3+ calculated to 68% which reveal a effective energy transfer.Analysis of refined data shows that Zn-based Zn3(BO3)(PO4)with weak crystal field environment(tetrahedral coordinated and five-coordinated)provides conditions for the red emission of Mn2+ at low coordination due to its distorted crystal structure,and achieves an interesting red emission of Mn2+ in the five-coordinated coordination.At the same time,Zn3(BO3)(PO4)can emit a blue range of light due to inherent defects,and a rare energy transfer between Tb3+and Mn2+ is found in the matrix.Then a series of color-tuning fluorescent powders produced thoughco-doping Tb3+,Mn2+ in Zn3(BO3)(PO4).(3)In the previous Zn3(BO3)(PO4): Tb3+,Mn2+phosphor,the emission spectra and Thermoluminescence glow curves were observed to show some fluctuations in the matrix spectra are attribute to the introduction of new shallow defects in the matrix by Tb3+,Mn2+.Temperature spectra reveal that Zn3(BO3)(PO4): Tb3+,Mn2+ Phosphor have good thermal stability,in which the phosphor does not exhibit thermal quenching even up to 200?(the emission of Mn2+)and 150?(emission of Tb3+).The interesting phenomenon arises from the formation of defect levels caused by active ions.The electron stays in the host jump to the excited state of activator.And the thermal active phonon-assisted excitation which caused the blue-shift also is the other reason for the abnormal phenomenon.