【摘要】 采用高温固相法合成α、β和γ-Zn3(PO4)2∶Mn2+,Ga3+(ZPMG),XRD分析表明,高温合成过程中淬火条件有利于β相的形成,退火条件有利于γ相的形成。三种磷光粉的激发光谱分别位于246 nm(α)、234nm(β和γ)的宽带谱。α相的发射光谱为位于508 nm的锐线谱,β和γ相的发射光谱均存在两个谱带,分别位于508 nm的绿色光谱区和616 nm的红色光谱区。两种发射均归属为Mn2+的4T1(4G)→6A1g(6S)跃迁,但是由于Mn2+在Zn3(PO4)2结构中的配位数不同,故发光颜色及强度均不同。对于余辉发射,只能观察到红色余辉光谱。更多还原

【Abstract】 Since the green long persistent phosphor SrAlO₄∶Eu²⁺,Dy³⁺ was reported in 1996,scientists（focused） their attention on rare earth doped aluminate,silicate or sulfide system.However,transition metal（ions）,e.g.,Mn²⁺,which shows efficient luminescence and highly-saturated color in many compounds,can act as efficient emission center for luminescent materials.Zinc orthophosphate has three crystalline modifications,labled as α,β and γ crystal phases.The red long-lasting phosphorescent properties of β-Zn₃（PO₄）₂∶ Mn²⁺_0.05,M³⁺（M=Al,Ga） have been reported by J.Wang,however,the phosphorescent properties of γ-Zn₃（PO₄）₂∶ Mn²⁺_0.05,Ga³⁺ were not reported up to now. The preparation of γ-Zn₃（PO₄）₂∶ Mn²⁺_0.05,Ga³⁺ have two processes: firstly,the stoichiometric amounts of raw materials were thoroughly mixed and ground in an agate mortar.Then the mixtures were pre-fired at 500 ℃ for 3 h;secondly,the pre-fired samples were thoroughly reground again,then sintered at 850 ℃ for three hours under a thermal-carbon reducing atmosphere by solid-state reaction.The XRD spectra show that,when the concentration of Mn²⁺>0.3%,quenching is contributed to the formation of β phase,but anneal is propitious to the formation of γ phase. The excitation and emission spectra show that,The three forms are excited at 234 nm（α）,and 246 nm（β and γ）,with emission peaks at 507 nm for α form,sharp peaks at both 507 nm and 616 nm for β,and sharp peak at 507 nm and weak peak at 616 nm for γ form.Both the two typical peaks are attributed to the（⁴T₁→）⁶A₁ transition of Mn²⁺.The emission color mostly depends on the coordination number（CN）.The Mn²⁺ ion emits green light when is tetrahedrally coordinated（CN=4） in the lattice whereas it emits red light in（octahedral） coordination（CN=6）. According to the long-lasting phosphorescence and decay measurement results,there is no long-lasting phosphorescent phenomenon in the α form,because there is no octahedrally coordinated Mn²⁺ in this structure.For the β and γ-ZPMG,the long-lasting phosphorescent emission band is also derived from the ⁴T_1g（⁴G） →⁶A_1g（⁶S） transition of Mn²⁺ in the host.The decay curves of β and（γ-ZPMG） can be divided into two processes: a fast and a slow one.After irradiated by UV lamp（254 nm） for 5min,the red phosphorescence of the Mn²⁺,Ga³⁺ co-doped β-ZPMG and γ-ZPMG are still observed in the dark for not less than 30 min and 15 min,respectively.更多还原