摘要
稀土掺杂纳米晶体是近年来发展起来的一种新型的发光材料。它同时具备了纳米材料和稀土离子的共同优点,在发光材料中占据着举足轻重的地位。本论文采用水热法制备了Eu3+/Tm3+:LaF3/LaOF纳米晶体和Eu3+,Pr3+单掺和共掺的LaF3和LaOF纳米晶体；应用激光光谱学技术研究了掺杂LaF3/LaOF纳米晶体的荧光发射性质,分析了纳米晶体基质性质、掺杂离子的局域环境、以及掺杂离子的性质和能级结构等因素对荧光发射性质的影响。主要内容分为以下三个部分：第一部分介绍了在水热法的基础上,利用水热-烧结法制备四方相结构的Eu3+,Tm3+单掺和共掺的LaOF, LaF3纳米晶体以及Eu3+,Pr3+单掺和共掺的LaOF, LaF3纳米晶体。第二部分研究讨论氟化物纳米晶体中由于离子共掺杂所引发的局域环境和对称性的变化,以及由此产生的共掺Tm3+离子对Eu3+离子的荧光增强效应。第三部分从掺杂离子的能级结构、性质、以及纳米晶体基质的对称性变化等因素出发,探讨了基质变化和离子共掺条件下掺杂稀土离子的荧光发射特性。
第一部分：四方相结构的LaOF:Eu3+/Tm3+; LaOF:Eu3+; LaOF:Tm3+; LaOF:Pr3+;
LaOF:Eu3+/Pr3+纳米晶体的水热-烧结法合成及其表征
应用水热-烧结法合成了具有四方相结构的LaOF:Ln3+纳米晶体。与已有的四方相结构的LaOF纳米晶体的合成技术相比较,该方法具有制作过程简单,制备条件要求低等优点。对于四方相结构的LaOF:Eu3+/Tm3+纳米晶体,当Eu3+的浓度为1.0 mol%时,发现其最强的红色荧光发射所对应的共掺Tm3+的最佳掺杂浓度为0.5m0l%。
第二部分：掺杂离子局域环境和对称性变化对LaOF:Eu3+/Tm3+纳米晶体中Eu3+的荧光发射性质的影响
采用激光光谱学的方法,分别研究了四方相结构的LaOF:Eu3+和LaOF:Eu3+/Tm3+中Eu3+的荧光发射。在532 nm的连续和脉冲激光激发下,观察到了源于Eu3+的5D1和5D0两个激发态的各个荧光辐射。其中共掺纳米晶体中Eu3+的5D0→7F2的受迫电偶极辐射跃迁对应的红色荧光发射强度明显的高于单掺纳米晶体中Eu3+所对应的荧光发射强度,其原因是由于Tm3+的掺入取代了LaOF中部分的Eu3+和La3+,使得Eu3+离子近邻某些方向上的键长因Tm3+的掺入而发生变化；同时离子间的相互作用也由La3+和Eu3+之间的作用变为La3+、Eu3+以及Tm3+之间的作用,这些变化均在一定程度上增加了Eu3+局域环境的不对称性,使Eu3+离子的f-f跃迁禁阻进一步被解除,从而Eu3+的红色荧光辐射强度得到大幅度地增强。
第三部分：基质结构以及激发光波长变化对LaF3/LaOF:Ln3+(Ln3+= Eu3+, Pr3*, Tm3+)荧光发射的影响
基质结构的改变为掺杂稀土发光离子提供了不同的局域环境,从而为改变和影响掺杂离子的荧光发射性质提供了条件。该部分采用激光光谱学的方法,在532nm，442 nm以及355 nm的激光激发下,研究了基质结构变化对于氟化物纳米晶体中的掺杂稀土Eu3+,Pr3+和Tm3+的荧光发射特性的影响规律以及同一基质中单掺和共掺稀土离子的荧光发射特性。依据掺杂离子的能级结构、性质、以及纳米晶体基质的对称性变化等因素,对所观测到的实验现象进行了分析研究,探讨了基质结构变化和离子再组合时,其掺杂共存离子的荧光发射特性。结果发现：当Pr3+和Tm3+分别与Eu3+共掺时,其红色荧光的辐射强度以及色纯度得到了一定的改善。
Rare earth doped Nanocrystal is a newly developed luminescent material that has both advantangeous of nanocrystal and rare earth (RE) ions. In cureent thesis, Eu3+/ Tm3+:LaF3/LaOF and Eu3+(Pr3+) doped LaF3 or LaOF nanocrystals are prepared by hydrothermal method. The spectroscopic properties of luminescence emission from RE doped- nanocrystals are investigated by laser spectroscopic methods. The influences of nanocrystal matrix, local environment and energy structure of doped ions on the fluorescence emission are studied experimentally. There are three parts included in the thesis. In the first part, we mainly introduce the preparation of core doped LaF3 and LaOF nanocrystals with hydrothermal method and hydrothermal-sintering method. In the second part, we discuss the symmetry and local environment change of nanocrystals caused by the dopping process. The enhancement effects of codoped Tm3+ ions to doped Eu3+ ions in LaF3 anf LaOF nanocrystals are studied. In the third part, we discuss the dependence of fluorescence emission on the mateix change and ions-doping based on energy configuration of doped ions and the symmetry change of nanocrystal matrix.
Part one:Synthesis and characterization of tetragonal LaOF:Eu3+/Tm3+, LaOF:Eu3+, LaOF:Pr3 and LaOF:Eu3+/Pr3+ nanocrystals prepared with hydrothermal-sintering method
Tetragonal LaOF:Ln3+ nanocrystals are successfully prepared with hydrothermal-sintering method that is simple and can be conducted at easier synthesizing conditions. It is found that in the tetragonal LaOF:(1.0 mol%)Eu3+/Tm3+, the strongest fluorescence emission from Eu3+ is obtained when the comcentration of codoped Tm3+ ion is 0.5 mol%.
Part two:Influence of the local environment and symmetry change on the fluorescence emission of Eu3+ in LaOF:Eu3+/Tm3+ nanocrystals
The optical transitions of Eu3+ in LaOF:Eu3+ and LaOF:Eu3+/Tm3+ nanocrystals with tetragonal crystal structures are studied with laser spectroscopic mehod. fluorescence emissions from 5D1 and 5D0 two excited states are observed when the samples are excited with 532 nm continuous and pulsed lasers. It is found that the intensity of red fluorescence emission, which resulted from the 5D0→7F2 forced electric-dipole transition, is obviously stronger in co-doped nanocrystal than that in the singled-coped nanocrystal. The reason is that Tm3+ substitute partial Eu3+ and La3+ in the LaOF nanocrystals so as to band length of some directions in Eu3+ nearby, at the same times, interionic reciprocity have changed from La3+ and Eu3+ to La3+、Eu3+ and Tm3+, the changes increased on the unsymmetry of local environment of Eu3+ and removed f-f forbidden transition thus the red fluorescence emission of Eu3+ in the LaOF:Eu3+/Tm3+ namocrystals was increased.
Part three: Dependence of matrix structure and excition wavelength to the fluorescence emission of Ln3+: LaF3/LaOF(Ln3+= Eu3+, Pr3*, Tm3+) nanocrystals
The change of matrix structure provids different local environment for doped ions, thus provided conditions for changing fluorescence emission properties of doped RE ions. The influence of matrix structure change on the fluorescence emission properties of Eu3+, Pr3+ and Tm3+ coped and codoped fluoride namocrystals are studied with laser excitations of 532 nm,442 nm and 355 nm. Based on the energy structure of doped ions and symmetry change of matrix, we have studied the experimental observations and fluorescence emission properties.The results shows that when Pr3+ and Tm3+ are coped to Eu3+ doped namocrystals, the intensity of red fluorescence emission and its colour purity can be improved significantly.
引文
[1]郑子樵,李红英.稀土功能材料[M].北京：化学工业出版社,2003：1-184.
[2]张志焜,崔作林.纳米技术与纳米材料[M].北京：国防工业出版社,2000：79-82.
[3]F.B. Li, X.Z. Li, C.H. Ao, M.F. Hou, S.C. Lee. Photocatalytic conversion of NO using TiO2-NH3 catalysts in ambient air environment[J]. Appl Catal. B:Environ, 2004,54:275-283.
[4]Jiaguo Yu, Guohong Wang, Bei Cheng, Minghua Zhou. Effects of hydrothermal temperature and time on the photocatalytic activity and microstructures of bimodal mesoporous TiO2 powders[J]. Appl. Catal. B:Environ,2007,69: 171-180.
[5]徐叙瑢,苏勉曾.发光学与发光材料[M].北京：化学工业出版社,2004：96-109.
[6]李建宇.稀土发光材料及其应用[M].北京：化学工业出版社,2003：154-155.
[7]宋峰,陈晓波.张光寅.Er3+/Yb3+共掺磷酸盐玻璃的发光与1.54mm激光性能[J].激光与光电子学进展,1997,4：15-25.
[8]张军杰,段中超.频率上转换掺稀土纳米微晶玻璃的研究进展[J].激光与光电子学进展,2005,42(6)：2-7.
[9]卡赞金.无机发光材料[M].北京：化学工业出版社,1980：23-36.
[10]刘光华.稀土材料与应用技术[M].北京：化学工业出版社,2005：293-307.
[11]孙家跃,杜海燕,胡文祥.固体发光材料[M].北京：化学工业出版社，2003：48-56.
[12]G. S. Yi, H. C. Lu, S. Y. Zhao. Synthesis, characterization, and biological application of size-controlled nanocrystalline NaYF4:Yb, Er infrared-to-visible up-conversion phosphors[J]. Nano Lett.,2004,4:2191-2196.
[13]G. Blasse, A. Baerner. Tunable photoluminescence in sol-gel derived silica xerogela[J]. Chem phys Lett,1973,20(6):573-574.
[14]何玲.稀土硼酸盐荧光粉的合成及其发光特性研究[D].兰州大学博士论文.
[15]卢利平等.稀土发光材料[M].北京：国防工业出版社,2005：10-15.
[16]钱逸泰.纳米和超细微粒的制备.全国第二届纳米固体学术讨论会论文集[C].1996.9-10.
[17]杨应国,胡小华,袁曦明.纳米稀土发光材料的研究与展望[J].矿产保护与利用,2005,5：44-47.
[18]冯华君,陈渊,唐芳琼等.单分散GdxY2-xO3:Eu3+纳米颗粒的制备及其荧光性能[J].感光科学与光化学,2006,24(3)：180-186.
[19]WANG H Z, GAO L, NIIHARA K. Synthesis of nanoscaled yttrium aluminumgarnet powder by the co-precipitation method[J]. Materials Science and Engineering A,2000,288(1):1-4.
[20]孙曰圣,陈达,魏坤等.纳米晶Y2O3:Eu3+的合成及其光谱性质研究[J].光谱学与光谱分析,2001,21(3)：339-342.
[21]RUAN S K, ZHOU J G, ZHONG A M, et al. Synthesis of Y3A15O12:Eu3+ phosphor by sol-gel method and its luminescence behavior[J]. Journal of Alloys and Compounds,1998,275:72-75.
[22]周建国,李振泉,赵凤英等.均分球形Y2O3:Eu3+纳米晶的制备[J].稀有金属材料与工程,2005,34(4)：332-334.
[23]CHEN L, HORIUCHI T, MORI T, et al. Postsynthesis hydrothermal restructuring of M41S mesoporous molecular sieves in water[J]. Journal of Physical Chemistry B,1999,103(8):1216-1222.
[24]HAKUTA Y, HAGANUMA T, SUE K, et al. Continuous production o f phosphor YAG: Tb nanoparticles by hydrothermal synthesis in supercritical water[J]. Materials Research Bulletin,2003,38(7):1257-1265.
[25]张巍巍,谢平波,张慰萍等.稀土正硼酸盐Ln,.xBO3: Eux(Ln=Y, Gd)的结构和与发光特性[J].无机材料学报,2001,16(1)：9-16.
[26]T HIRAI, T HIRANO, I KOMASAWA. Preparation of Gd2O3:Eu3+ and Gd2O2S: Eu3+ ph- osphor fine particles using an emulsion liquid membrane system [J]. Journal o f Colloid and Inter- face Science,2002,253(1):62-69.
[27]H W SONG, J W WANG, CHEN B J, et al. Size-dependent electronic transition rates in cubic nanocrystalline europium doped yttria [J]. Chemical Physics Letters,2003,376(1/2):1-5.
[28]D SUNL, C Qing, C S LIAO,et al.Luminescent properties o f Li+ doped nano-sized Y 2O3:Eu [J]. Solid State Communications,2001,119(6):393-396.
[29]周永慧,林君,于敏等.喷雾热解法制备发光材料研究进展[J].发光学报,2002,23(5)：503-508.
[30]E J Kim, Y C Kang, H D Park, et al. UV and VUV characteristics of (YGd)2O3: Eu phosphor particles prepared by spray pyrolysis from polymeric precursors [J]. Materials Research Bulletin,2003,38(3):515-524.
[31]姚疆,孙聆东,钱程等.稀土纳米复合氧化物RE2O3:Eu (RE=Y,Gd)的制备及特性[J].中国稀土学报,2001,19(5)：426-429.
[32]刘长久,叶乃清,刁汉明.纳米氧化镍氢氧化镍复合电极材料的制备及其电化学性能[J].应用化学,2001,18(4)：335-337.
[33]LI F, YU X H, PAN H J,et al. Syntheis of MO2 (M= Si, Ce, Sn) nanoparticles by solid-state reactions at ambient temperature[J]. Solid State Sciences,2000,2 (8): 767-772.
[34]TISSUE B M, YUAN H B. Structure, particle size and annealing o f gas phasecondensed Eu3+:Y2O3 nanophosphors [J]. Journal o f Solid State Chemistry,2003,171(1/2):12-16.
[35]SCHMECHE L R, WINKL ER H, Li X M, et al. Photoluminescence properties of nanocrys- talline Y2O3:Eu3+ in different environments [J]. Scripta Materialia, 2001,44(8/9):1213-1217.
[36]刘吉平,廖莉玲.无机纳米材料[M].北京：科学出版社,2003：117-119.
[37]邱关明,耿秀娟,陈永杰.纳米稀土发光材料的光学特性及软化学制备[J].中国稀土学报,2003,21(2)：109-113.
[38]Q IAN G L I, L IAN GAO, YAN DON GSHEN G. Effects of grain size on Wavelength of Y2O3:Eu3+ emission spectra[J]. NanoStructured Materials.1997, 8 (7):825-831.
[39]KONRAD A, T FRIES, A GAHN, et al. Chemical vapor synthesis and luminescence p- roperties of nanocrystal line cubic Y2O3:Eu3+[J]. Journal of Applied Physics,1999,86 (6):3129-3133.
[40]TAO YE, ZHAO GU WEN, ZHANG W EI PING, et al. Combustion synthesis and photolum- ines of nanocrstallineY2O3:Eu3+ phoshors[J]. Materials Research Bullet in,1997,32 (5):501-506.
[41]张慰萍,尹民.稀土掺杂的纳米发光材料的制备和发光[J].发光学报，2000,21(4)：314-319.
[42]尹民,楼立人,张慰萍等.纳米微晶X1- Y2Si05:Eu3+中两种发光中心之间的能量传递研究[J].发光学报,1998,19(3)：216-219.
[43]Takayuki Hirai, Takashi Hirano, Isao Komasawa. Preparation of Gd2O3:Eu3+ and Gd2O2S:Eu3+ phosphor fine particles using an emulsion liquid membrane system[J]. Journal of Colloid and Interface Science,2002,253(1):62-69.
[44]Hongwei Song, Jiwei Wang, Baojiu Chen. Size dependent electronic transition rates in cubic nanocrystalline europium doped yttria[J]. Chemical Physics Letters, 2003,376(1/2):1-5.
[45]Q IAN G L I, L IAN GAO, YAN DON GSHEN G, Effects of grain size on Wavelength of Y2O3:Eu3+ emission spectra [J]. NanoStructured Materials.1997,8 (7):825-831.
[46]Sung-Jei Hong, Min-Gi Kwak, Jeong-In Han. Optimization of solvent condition for highly luminescent Y2O3:Eu3+ nanophosphor[J]. Current Applied Physics, 2006,6:211-215.
[47]Bing Yan, Jian Hua Wu. Solid state-hydrothermal synthesis and photoluminescence of LaVO4:Eu3+ nanophosphors[J]. Materials Letters,2009, MLBLUE-10214:1-3.
[48]Chih-Cheng Lin, Kuo-Min Lin, Yuan-Yao Li. Sol-gel synthesis and photoluminescence characteristics of Eu3+-doped Gd2O3 nanophosphors[J]. Journal of Luminescence,2007,126:795-799.
[49]Xiaozhong Cui, Weidong Zhuang, Zhijian Yu. Preparation of red phosphor (Y, Gd)BO3:Eu by soft chemistry methods[J]. Journal of Alloys and Compounds, 2008,451:280-285.
[50]Abhay D. Deshmukh, S. J. Dhoble, Animesh Kumar. New Eu activated ZnMgAl10O17 nanophosphor[J]. Journal of Alloys and Compounds,2008, JALCOM-18 185:1-4.
[51]Soung-soo Yi, Jong Seong Bae, Byung Kee Moon. Highly enhaced luminescence of nanocrystalline TiO2:Eu3+ phosphors[J]. Optical Materials,2006,28:610-614.
[52]Jong Su Kim, Ae Kyung Kwon, Jin Su Kiml. Optical and structural properties of ZnGa2O4:Eu3+ nanophosphor by hydrothermal method[J]. Journal of Luminescence,2007,122-123:851-854.
[53]霍尔(Hall, J.L.),卡尔斯登(Carlsten, J.L.).激光光谱学Ⅲ[M],北京：北京科学出版社.1985：112-117.
[54]黄世华.激光光谱学原理和方法[M].长春：吉林大学出版社.2001：7-9.
[55]陆维敏,陈芳,谱学基础与结构分析[M].北京：高等教育出社.2004：99-100.
[56]Ksenia Dolgaleva, Robert W. Boyd, Peter W. Milonni. Influence of local-field effects on the radiative lifetime of liquid suspensions of Nd:YAG nanoparticles [J]. J. Opt. Soc. Am. B,2007,24(3):516-521.
[57]Markus P. Hehlen, Gabriela Frei, Hans U. Gudel. Dynamics of infrared-to-visible upconversion in Cs3Lu2Br3:l% Er3+[J]. Physics Review B,1994,50(22): 16264-16273.
[58]马义,闫阔,杨波.掺杂稀土离子发光动力学模型[J].物理学报,1999，48(7)：1361-1371.
[59]J. Garcia-Adeva, R. Balda, J. Fernandz. Dynamics of the infrared-to-visible upconversion in an Er3+ -doped KPb2Br5 crystal[J]. Physics Review B,2005,72: 165116-1-165116-11.
[60]Tang W J, Chen D H, Wu M. Luminescence studies on SrMgAl10O17:Eu, Dy Phosphor crystal. Optics & Laser Technology,2009,41(1):81-84.
[61]张彦辉,颜剑波,阎晓琦等.惰性离子(La3+, Y3+, Gd3+)对配合物苯乙酮酸邻菲咯啉铕荧光性能的影响.光谱学与光谱分析,2007,27(3)：525-529.
[62]Boitier F, Hidaka C, Takizawa T. Enhancement of Mn red emission in CaGa2S4 compounds by co-doping rare-earth elements. J Lumin,2009.129(5):554-562.
[63]郑玉山,李文先,陈丽娟.对甲苯基苯乙烯基亚砜稀土高氯酸盐体系中Tm3+→Eu3+的荧光增强效应.稀土,2008,29(5)：20-23.
[64]陈丽娟,李文先,王红胜等.对甲基苯甲酰甲基亚砜高氯酸盐体系中Tm3+Pr3+对 Eu3+的荧光增强效应.稀土,2008,29(2)：15-19.
[65]Boitier F, Hidaka C, Takizawa T. Enhancement of Mn red emission in CaGa2S4 compounds by co-doping rare-earth elements. J Lumin,2009,129(5):554-562.
[66]雷瑜,郑海荣*，田宇等.氟化物纳米晶体中Tm3+对Eu3+的荧光增强效应.科学通报,2010,55(11)：978-983.
[67]霍尔,卡尔斯登.激光光谱学Ⅲ[M].王淑瑚等译。北京：北京科学出版社,1985.
[68]黄世华.激光光谱学原理和方法[M].长春：吉林大学出版社,2001：7-9.
[69]陆维敏,陈芳.谱学基础与结构分析[M].北京：高等教育出社,2004：99-100.
[70]陈扬骎,杨晓华.激光光谱测量技术[M].上海：华东师范大学出版社,2006：172-179.
[71]杨建虎,戴世勋,戴能利等.掺Er3+铋酸盐玻璃的荧光光谱分析.光谱学与光谱分析,2003,23(6)：1065-1068.
[72]刘吉平,廖莉玲.无机纳米材料.北京：科学出版社,2003，117.
[73]Dijken A V, Meulenkamp E A, Vanmaekelbergh D, et al. The luminescence of nanocrystalline ZnO particles:the mechanism of the ultraviolet and visible emission. J Lumin,2000,87-89:454-456.
[74]Tissue B M, Yuan H B. Structure, particle size, and annealing of gas phase-condensed Eu3+:Y2O3 nanophosphors. J Solid State Chem,2003,171(1-2): 12-18.
[75]李尔东,宋晓艳,张久兴等.晶态与非晶态双相结构的纯稀土纳米块体材料及其制备机制.科学通报,2006,51(20)：2448-2452.
[76]綦艳,孟建新,时朝璞.纳米长余辉发光材料CaTiO3:Pr的制备及表征.光谱学与光谱分析,2007,27(7)：1287-1290.
[77]Ternane R, Trabelsi-Ayedi M, Kbir-Arigui N, et al. Luminescent properties of Eu3+ in calcium hydroxyapatite. J Lumin,1999,81 (3):65-170.
[78]Bol A A, Meijerink A. Long-lived Mn2+ emission in nanocrystalline ZnS:Mn2+. Phys Rev B,1998,58(24):15997-16000.
[79]Dejneka M, Snitzer E, Riman R E. Blue, green and red fluorescence and energy transfer of Eu3+ in fluoride glasses. J Lumin,1995,65(5):227-245.
[80]Todoroki S, Tanabe S, Hirao K, et al. Phonon sideband spectra and local structure around Eu3+ ions in sodium silicate glasses. J Non-Cryst. Solids,1991,136(3): 213-218.
[81]Capobianco J A, Proulx P P, Bettinelli M, et al. Absorption and emission spectroscopy of Eu3+ In metaphosphate glasses. Phys Rev B,1990,42(10):5936-5944.
[82]Babu P, Jayasankar C K. Optical spectroscopy of Eu3+ ions in lithium borate and lithium fluoroborate glasses. Phys Rev B,2000,279(4):262-281.
[83]Henderson B, Imbusch G. F. Optical Spectroscopy of Inorganic Solids. New York: Clarendon.Press.Oxford,1989,395.
[84]张庆礼,何伟,孙敦陆,等.Judd-Ofelt光谱分析理论.光谱学与光谱分析,2005,25(3)：329-333.
[85]王芙香,裴松皓,彭慰先,等.透明光学树脂中Eu3+辐射参数的理论和实验研究.光谱学与光谱分析,2006,26(2)：248-250.
[86]Babu S S, Babu P, Jayasankar C K, et al. Optical absorption and photoluminescence studies of Eu3+-doped phosphate and fluorophosphate glasses. J Lumin,2007,126(1):109-120.
[87]张思远,毕宪章.稀土光谱理论.长春：科技出版社,1991,1.
[88]Long M, Hong F S, Li W, et al. Size-dependent microstructure and europium site preference influence fluorescent properties of Eu3+-doped Ca10(PO4)6(OH)2 nanocrystal. J Lumin,2008,128:428-436.
[89]何恩节,郑海荣,张喜生,等.四方相氟氧化镧掺铕离子红色纳米荧光粉的制备方法.专利,CN101417788,2009-04-29.
[90]Zhang T, Guo H, Qiao Y M Facile synthesis, structural and optical characterization of LnF3:Re nanocrystals by ionic liquid-based hydrothermal process [J]. J. Lumin,2009,129:861-866.
[91]Liu Y F, Chen W, Wang S P, et al X-ray luminescence of LaF3:Ce3+, Tb3+ Water-soluble nanoparticles [J]. J. Appl Phys,2008,103(6):063105.
[92]Liu C H, Sun J, Wang H, et al Shear fracture of bulk metallic glasses with controlled [J]. J. Scripta Materialia,2008,58 (2):111-114.
[93]Zalewska M, Klonkowski A M Energy transfer from TiO2 nanocrystals to Tb3+ ion incorporated into silica [J]. Optical Materials,2008,30:725-729.
[94]Jia G, Song Y H, Yang M, et al Uniform YVO4:Ln3+ (Ln= Eu, Dy, and Sm) nanocrystals: Solvothermal synthesis and luminescence properties [J]. Optical Materials,2009,31:1032-1037.
[95]Dwivedi Y, Rai A, Rai S B Energy transfer in Er: Eu:Yb:co-doped tellurite glasses:Yb as enhancer and quencher [J]. J. Lumin,2009,129:629-633.
[96]Fabien Boitier, Chiharu Hidaka, Takeo Takizawa Enhancement of Mn red emission in CaGa2S4 compounds by co-doped rare-earth elemrnts [J]. J. Lumin, 2009 129(5):554-562.
[97]Stouwdam J W, Van Veggel F C J M. Near-infrared Emission of Redispersible Er3+, Nd3+, and Ho3+ Doped LaF3 Nanoparticles[J]. J. Nano Lett.2002,2(7): 733-737.
[98]Kumar V U, Rao D R, Venkateswarlu P. Optical absorption and laser excited fliorescence spectra of LaF3:Eu3+[J]. J. Chem. Phys,1977,66(5):2019-2025.
[99]Georgescu S, Toma O, Chinie A M, et al. Excited state dynamics of Eu3+ in the partially disordered crystals La3Ga5SiO14 and La3Ga5.5Tao.5O14 [J]. J. Lumin,2008, 128(5-6):741-743.
[100]Kityk I V, Wasylak J, Kucharski J, et al. PbO-Bi2O3-Ga2O3-BaO-Dy3+ glasses for IR luminescence [J]. J. Non-Cryst Solids,2002,297(2-3):285-289.
[101]Babu P, Jayasankar C K. Optical spectroscopy of Eu3+ ions in lithium borate and lithium fluoroborate glasses [J]. Phys Rev B,2000,279(4):262-281.
[102]Wang X J, Huang S H, Reeves R, et al. Studies of the spectroscopic properties of Pr3+ doped LaF3 nanocrystals/glass [J]. J. Lumin,2001,94-95:229-233.
[103]Donega C D M, Dirksen G J, Folkerts H F, et al. The vibronic spectroscopy and luminescence concentration quenching of the Pr3+ ion in La2CO3, LaOF and LiYF4 [J]. J. Phys Chem Solids,1995,56(2):267-276.
[104]Gaspers H H, Rast H E, Buchanan R A Energy levels of Pr3+ in LaF3 [J]. J. Chem Phys,1965,43(6):2124-2128.
[105]Zheng H R, Gao D L, Zhang X Y, et al. Fluorescence characteristics of Tm3+ in different local environments[J]. J. Appl. Phys.,2008,104:013506.
