采用高温固相法按化学式ZnxMg(1-x)Ga2O4∶Cr3+(x=0,0.2,0.6,0.8,1.0)配比原料制备了一系列红色长余辉发光材料。X射线衍射(XRD)分析表明样品物相均为面心立方结构。光致发光特性表明样品的红光发射峰均由以Cr3+为发光中心的电子2 E—4 A2跃迁所致,Cr3+的激发带与基质发射带之间有大面积重叠,两者间存在有效的能量传递。余辉衰减曲线与热释光谱分析表明,不同Zn掺入量的样品余辉衰减快慢不同,是由于其中存在的陷阱能级深度不同,且陷阱能级越深,其余辉时间越长。
A series of red long afterglow phosphors with composition ZnxMg(1-x)Ga2O4∶Cr3+(x=0,0.2,0.6,0.8,1.0)were synthesized by a high temperature solid-state reaction method.The X-ray diffraction studies show that the phase of the phosphors is face-centered cubic structure.Photoluminescence spectra show that the red emission of Cr3+ originated from the transition of 2E—4A2.Due to the large overlap between absorption band of Cr3+ and emission band of the host.Cr3+ could obtain the excitation energy from the host via the effective energy transfer.The afterglow decay characteristics show that the phosphor samples with different Zn contents have different afterglow time and the afterglow time also changes with the value of x.The measurement of thermoluminescence reveals that the trap depth of the phosphor samples with different Zn contents is different.The samples with deeper traps have longer afterglow time.