摘要
采用高温固相法成功合成了纯相的LaPO_4:Pr~(3+), YPO_4:Pr~(3+)以及YPO_4:Bi荧光粉,通过XRD对样品进行物相分析表明,磷酸镧为单斜相晶系,磷酸钇为四方晶系。分别探究了在X射线激发下的UVC发光性质以及在X射线激发后的UVC余辉性质,发现这3种荧光粉在X射线激发下都具有强烈的UVC发射,发现在X射线激发后YPO_4:Pr~(3+)和YPO_4:Bi荧光粉都具有UVC余辉发射,其中, YPO_4:Pr~(3+)荧光粉的UVC余辉可持续5 min以上,而YPO_4:Bi荧光粉的UVC余辉可持续1 h以上。单独对YPO_4:Pr~(3+)荧光粉进行了热释发光分析,并估算出其陷阱距离导带的位置,对其产生UVC余辉的机制进行了系统的描述和解释。
The pure phase LaPO_4:Pr~(3+), YPO_4:Pr~(3+) and YPO_4:Bi phosphors were successfully synthesized through conventional solid state reaction. The characterization of the samples by XRD showed that LaPO_4 phosphor was monoclinic crystal system and YPO_4 phosphor was tetragonal. The UVC luminescence properties upon X-ray excitation and the UVC persistent luminescence properties after X-ray excitation were explored respectively. It was found that all three phosphors had strong UVC emission under X-ray excitation, and it was also found that both YPO_4:Pr~(3+) and YPO_4:Bi phosphors had UVC persistent luminescence after X-ray excitation, among which the UVC afterglow of YPO_4:Pr~(3+) phosphor could last for more than 5 min, while the UVC afterglow of YPO_4:Bi phosphor could last for more than 1 h. The thermoluminescence analysis of YPO_4:Pr~(3+) phosphor was carried out, and the position of the trap was estimated. The mechanism for generating UVC afterglow was systematically described and explained.
引文
[1]Valero A,Begum M,Leong S L,Hocking A D,Ramos A J,Sanchis V,Marin S.Effect of germicidal UVClight on fungi isolated from grapes and raisins[J].Lett.Appl.Microbiol.,2007,45(3):238.
[2]Zahir F,Rizwi S J,Haq S K,Khan R H.Low dose mercury toxicity and human health[J].Environ.Toxicol.Pharmacol.,2005,20(2):351.
[3]Harada M.Minamata disease:methylmercury poisoning in Japan caused by environmental pollution[J].Crit.Rev.Toxicol.,1995,25(1):1.
[4]程伟雪.水俣公约---新的多边环境协议[J].环境保护,2013,41(9):27.Cheng W X.Minamata Convention-new multilateral environmental agreement[J].Environmental Protection,2013,41(9):27.
[5]Han J,Crawford M H,Shul R J,Figiel J J,Banas M,Zhang L,Nurmikko A V.Al Ga N/Ga N quantum well ultraviolet light emitting diodes[J].Appl.Phys.Lett.,1998,73(12):1688.
[6]Awater R H P,Niemeijer-Berghuijs L C,Dorenbos P.Luminescence and charge carrier trapping in YPO4:Bi[J].Opt.Mater.,2017,66:351.
[7]Ofelt G S.Intensities of crystal spectra of rare-earth ions[J].Journal of Chemical Physics,1962,37(3):511.
[8]Gao F,Zhang S.Investigation of mechanism of nephelauxetic effect[J].J.Phys.Chem.Solids,1997,58(12):1991.
[9]杨水金,袁良杰,孙聚堂.掺杂Eu3+离子La PO4的合成及其发光特性研究[J].发光学报,2003,24(5):527.Yang S J,Yuan L J,Sun J T.Synthesis and luminescent properties of Eu3+doped La PO4[J].Acta Luminescens Sinica,2003,24(5):527.
[10]Srivastava A M,Camardello S J.Concentration dependence of the Bi3+luminescence in Ln PO4(Ln=Y3+,Lu3+)[J].Opt.Mater.,2015,39:130.
[11]Johnson T A,Rehak E A,Sahu S P,Ladner D A,Cates E L.Bacteria Inactivation via X-ray-induced UVC radioluminescence:toward in Situ biofouling prevention in membrane modules[J].Environ.Sci.Technol.,2016,50(21):11912.
[12]Pan Z,Lu Y Y,Liu F.Sunlight-activated long-persistent luminescence in the near-infrared from Cr3+-doped zinc gallogermanates[J].Nat.Mater.,2012,11(1):58.
[13]Xu Z,Gu W B,Feng H,Zhang Z J,Zhao J Z.Enhancement of structure stability and luminescence intensity of Li YF4:Ln3+nanocrystals[J].J.Rare Earths,2017,35(9):844.
[14]Li Y,Zhou S F,Li Y Y,Sharafudeen K,Ma Z J,Dong G P,Peng M Y,Qiu J R.Long persistent and photostimulated luminescence in Cr3+-doped Zn Ga Sn O phosphors for deep and reproducible tissue imaging[J].J.Mater.Chem.C,2014,2(15):2657.
[15]Guo C F,Tang Q,Zhang C X,Huang D X,Su Q.Thermoluminescent properties of Eu2+and RE3+codoped phosphors Ca Ga2S4:Eu2+,RE3+(RE=Ln,excluding Pm,Eu and Lu)[J].J.Lumin.,2007,126(2):333.
[16]Kshatri D S,Khare A.Characterization and optical properties of Dy3+,doped nanocrystalline Sr Al2O4:Eu2+,phosphor[J].J.Alloys Compd.,2014,588:488.
[17]Jain V K,Jahan M S.Thermal activation energies and peak temperatures in thermoluminescence of Li F(Mg,Ti)and Ca F2:Mn at low temperatures[J].Phys.Status Solidi A,1987,102(2):725.
[18]Beattie A R,Landsberg P T.Auger effect in semiconductors[J].Proc.R.Soc.London,1959,249(1256):73.