Synthesis And Characterization Of Novel Bluish-green Long-lasting Phosphorescence Phosphors

The long-lasting phosphorescence?LLP?counts as an optical phenomenon of great significance.The luminescence is able to be observed after ceasing the excitation in a couple of minutes and even more a longer time several hours.Because of this features,the LLP materials can be adopted in night displays,security signs,optical storage medias,vivo bio-imaging and other specific domains.From early stage of sulfide host materials to today's aluminate and silicate host materials,a lot of green and blue LLP materials have been developed and applied commercially.However,there are still some problems in this research field such as ambiguity of afterglow mechanisms,monotony of emitting colors,etc.On this issues,this paper mostly studies the silicate host material of BaLu₂Si₃O₁₀:Eu²⁺,Nd³⁺,phosphate host materials of Ba₇Zr?PO₄?₆:Dy³⁺and Ca₉Y?PO₄?₇:Eu²⁺,Er³⁺/Ho³⁺.Based on research results of their afterglow properities,afterglow mechanisms implied in their experiment data were proposed.A newly bluish-green LLP Ba Lu₂Si₃O₁₀:Eu²⁺,Nd³⁺is presented and prepared.The initial LLP intensity shall be in the vicinity of 0.013 cd/m² and its LLP can continue for in excess of 6 h over the intensity level able to be recognized?0.32mcd/m²?.According to the rietveld structural refinement,energy band calculation and multicomponent spectral fitting,an interesting phenomenon that the blue emitting phosphor shows that bluish-green phosphorescence has been explained successfully.Phosphate host material Ba₇Zr?PO₄?₆ has luminescence and afterglow phenomenon without doping rare earth ions.Dy³⁺ions were designed to improve the afterglow performance.The long-lasting phosphorescence can last 147 s.Through the contrast between the emission spectrum of host and the phosphorescence spectrum of Ba₇Zr?PO₄?₆:Dy³⁺,the research of thermoluminescence curves.It is found that the trap which from intrinsic defect of host is the main reason of afterglow.A bluish-green phosphate LLP Ca₉Y?PO₄?₇:Eu²⁺,Er³⁺/Ho³⁺is prepared successfully when Eu²⁺and Er³⁺/Ho³⁺ions act as luminescence centers and trap centers.Bycomparing with single doping and co-doping thermoluminescence curves and LLP decay curves,we analyzed the reasons for the unobvious increase in the time of afterglow.