摘要
过去二十几年里,稀土掺杂上转换发光材料在三维立体显示、全固态激光器、红外探测等领域的广泛应用,引起了人们极大的研究兴趣。随着纳米科技的兴起,纳米上转换发光材料也成为上转换发光材料中新的研究热点,特别是作为生物荧光标签在生物检测领域具有广泛的应用前景。与传统染料标签相比,上转换荧光标签具有高灵敏性、抗漂白、高稳定性、环境影响小等优点。但稀土离子能级丰富,激发时常有多条谱线,而单带发射是生物标签实现多目标识别及多分子追踪的一个基本要求。另一方面,利用上转换白光纳米晶作为生物荧光标签,能够提供更多的同时检测通道,并能使荧光标签很好区别于环境色彩。目前关于稀土掺杂纳米晶上转换单一谱线及白光发射的报道却比较少,因此如何在稀土上转换材料中实现高纯单色发射或白光发射,提高识别效率成为当前上转换纳米荧光材料作为荧光探针在生物检测领域所面临的挑战之一。本文分别制备了稀土掺杂ZnO纳米晶和稀土掺杂NaYF4纳米棒粉末样品,结合Raman光谱、X射线衍射(XRD)、透射电镜(TEM)以及荧光光谱对样品的微结构和单带上转换可调荧光发射及上转换白光发射进行了研究。主要内容如下:
第一部分采用化学燃烧法制备了一系列Er~(3+)单掺和Er~(3+)-Li~+共掺杂ZnO纳米粉末样品,结合Raman光谱和XRD衍射光谱对样品的晶体结构进行了表征。结果表明热处理可以改善稀土掺杂ZnO纳米晶结晶质量,而Li~+离子共掺杂能够有效促进稀土离子融入ZnO基质中。上转换荧光光谱则表明Er~(3+)单掺样品在980nm激光激发下以红色上转换荧光(660nm)为主,而Er~(3+)-Li~+共掺杂样品则以绿光(535nm和557nm)为主,都呈现出良好的单色性。实验表明通过Li~+离子共掺杂,可以有效调节Er~(3+)掺杂ZnO样品的单带上转换荧光发射,有望作为多彩荧光生物标签得到应用。
第二部分采用水热合成法190℃时制备了一系列高纯单一晶相的六角稀土掺杂的NaYF4纳米棒。其中Yb~(3+)/Er~(3+)/Tm3+及Yb~(3+)/Ho3+/Tm3+三掺β-NaYF4纳米棒样品,在980nm激光激发下观察到了由上转换红、绿、蓝三基色拟合白光,样品的CIE色坐标值分别为(X=0.310, Y=0.340; X=0.316,Y=0.345)。不同激发功率密度下样品荧光光谱对样品上转换荧光特性分析表明Yb~(3+)/Er~(3+)/Tm3+及Yb~(3+)/Ho3+/Tm3+三掺β-NaYF4纳米棒样品红、绿、蓝波段上转换荧光强度对激发功率密度的响应不一致,与Yb~(3+)/Er~(3+)/Tm3+三掺β-NaYF4白光样品相比,Yb~(3+)/Ho3+/Tm3+三掺β-NaYF4白光样品有更宽的功率密度适用范围。
In pase twenty years, rare-earth-doped materials have been extensively investigated because of the promising application in the flat-panel displays, solid-state lasers, infrared detection, and biological detection and so on. In recent years, with development of nanotechnology, lanthanide-doped upconversion nanocrystals have been developed as a new class of luminescent optical labels that have become promising alternatives to organic fluorophores and quantum dots for applications in biological assays and medical imaging. These techniques offer low autofluorescence background, large anti-Stokes shifts, sharp emission bandwidths, high resistance to photobleaching, and high penetration depthand temporal resolution. Especially, with the application of biological multicolor fluorescent labels in multi-parameter detection, imaging and tracking of multiple molecular targets, narrow band radiations with high efficient luminescence in different wavelength ranges are needed. On the other hand, the white light upcoversion nanocrystal can provide more simultaneous detection channel as biological fluorenscent labels, farther distinguish marks from environmental colours. However, few works are reported about single band UC emission and white UC emissions in lanthanide-doped nanocrystals with the purpose of fluorescent labels in biological applications. Based on this background, in this dissertation, a series of rare earth doped ZnO nanoparticle and NaYF4 one-dimensional structure were prepared by chemical combustion method and hydrothermal, respectively. The structural and optical properties of the prepared samples were studied using Raman spectra, x-ray diffraction (XRD),? transmission electron microscopy (TEM) and up-conversion luminescent spectra, the influence of co-doped Li+ ions on the single band emission of ZnO:Er~(3+) nanocrystal and the influence of pump power desity on white UC luminescence of the NaYF4 was analyzed. The major contents of our study as follows:
In the first part, Er~(3+) doped ZnO nanoparticle were prepared by chemical combustion method. The red up-conversion luminescence was observed under 980nm excitation. Furthermore, a luminescent switching between the main red UC emission at 660nm and green one centered at 535nm and 557nm assigned to the transitions of 2H11/2/ 4S3/2→4I15/2 was presented through Li+ co-doping.? The origin of luminescent switching could be attributed to the modification of local crystal field around Er~(3+) ions due to the introduction of Li+ ions, and should be a promising upconversion phosphor for optoelectronic or biological applications. ?
In the second part, high-quality hexagonal phase rare-earth-doped NaYF4 nanorods was prepared by hydrothermal method at 190℃. Bright white light was produced under 980nm laser excitation through synthesis of red, green, blue upconversion luminescence in Tm3+/Ho3+/Yb~(3+) tridoped and Tm3+/Er~(3+)/Yb~(3+) tridoped NaYF4 nanorods, respectively. The perfect white light with (X=0.310, Y=0.340) and (X=0.316,Y=0.345) in Tm3+/Ho3+/Yb~(3+) tridoped and Tm3+/Er~(3+)/Yb~(3+) tridoped NaYF4 nanorods were obtained by adjusting the pump power density, respectively. Based on the power dependent spectral analyses,it was found that the pump power density response is different of red, green, blue emission in Tm3+/Ho3+/Yb~(3+) tridoped and Tm3+/Er~(3+)/Yb~(3+) tridoped NaYF4 nanorods. and Tm3+/Ho3+/Yb~(3+) tridoped sample have much wider range of power density response, relatively.
引文
[1]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.
[2]肖志国.蓄光型发光材料及其制品[M].北京:化学工业出版社, 2002.
[3]刘光华.稀土材料与应用技术[M].北京:化学工业出版社, 2005.
[4] Heer S, Kompe K, Gudel H U, Haase M. Highly efficient multicolour upconversion emission in transparent colloids of lanthanide-doped NaYF4 nanocrystals [J].Adv.Mater. 2004,16:2102-2105.
[5] Wang F, Liu X G. Recent advances in the chemistry of lanthanide-doped upconversion nanocrystals [J]. Chemical Society Reviews,2009, DOI: 10.1039/b809132
[6] Yi G S, Lu H C, Zhao S Y, Guo L H, et al. Synthesis, characterization, and biological application of size-controlled nanocrystalline NaYF4:Yb,Er infrared-to-visible up-conversion phosphors [J]. Nano. Lett. 2004, 4:2191.
[7] Wang L, Yan R X, Wang X, Peng Q, Li Y D, et al. Fluorescence Resonant Energy Transfer Biosensor Based on Upconversion-Luminescent Nanoparticles [J]. Angew. Chem., Int. Ed., 2005, 44:6054.
[8]张希艳,卢利平,柏朝晖,等.稀土发光材料[M].北京:国防工业出版社, 2005.
[9]杨华明,欧阳静,史蓉蓉,等.稀土激活发光材料的研究进展[J].材料导报, 2002, 16(7): 31-34.
[10] Bitter F. The optical detection of radio frequency resonance [J]. Phys. Rev., 1949, 76: 833-835.
[11] Kastler A. Les methods optiques d’orientation atomique et leurs application [J]. Proc. Phys. Soc., 1954, 67(10): 853-863.
[12] Auzel F. Compteur quantique par transfert d’energie entre deux ions de terres rares dans. unverre[J]. C.R. Acad. Sci. (Paris), 1966, 2623: 1016-1019.
[13] Auzel F. Compteur quantique par transfert d’energie entre de Yb3+ a Tm3+ dans un tungstate mixte et dans verre germinate [J]. C.R. Acad. Sci. (Paris), 1966, 263: 819-821.
[14]何捍卫,周科朝.红外-可见光的上转换材料研究进展[J].中国稀土学报, 2004, 21(2): 123-128.
[15] Auzel. F. Upconversion and anti-stokes processes with f and d ions in solids [J]. Chem. Rev., 2004, 104: 139-173.
[16] Chivian J S, Case W E, Eden D D. The photon avalanche: A new phenomenon in Pr3+-based infrared quantum counters [J]. Appl. Phys. Lett., 1979, 35:124-126.
[17] Fujiwara H, Sasaki K, et al. Upconversion lasing of a thulium-ion-doped fluorozirconate glass microsphere [J]. J. Appl. Phys., 1999, 85(5):2385-2388.
[18] Grubb S G, Bennett K W, Cannon R S, et al. CW room-temperature blue upconversion fiber laser [J]. Electronics Lett., 1992, 28:1243-1244.
[19] Goh S C, Pattie R, Byme C, et al. Blue and red laser action in Nd3+, Pr3+ codoped fluorozirconate glass[J]. Appl. Phys. Lett., 1995, 67(6):768-770.
[20]冯衍,陈晓波,宋峰,等. 798nm半导体激光激发下Yb3+/Tm3+:ZBLAN玻璃的上转换发光[J].光学学报, 1999, 19(4): 552-556.
[21] Gouveia-Neto A S, Bueno L A, do Nascimento R F, et al. White light generation by frequencyupconversion in Tm3+/Ho3+/Yb3+-codoped fluorolead germanate glass[J] Appl. Phys. Lett. 2007, 91:091114
[22] Auzel F, Pecile D, Morin D. [J]. J Electrochem. Soc., 1991, 29:1135.
[23] Wang Y D, Ohwaki J. New transparent vitroceramics co-doped with Er3+ and Yb3+ for efficient frequency up-conversion [J]. Appl. Phys. Lett., 1993, 63:3268-3270.
[24]秦冠仕,秦伟平,陈宝玖,鄂书林,葛中久,任新光,黄世华.氟氧化物玻璃陶瓷中高效低阈值的红色上转换发光现象[J].光谱学与光谱分析, 2002,5(22):705-708.
[25] Lahoz F, Martin I R, Calvilla-Quintero J M. Ultraviolet and white photon avalanche upconversion in Ho3+-doped nanophase glass ceramics [J]. Appl. Phys. Lett., 2005, 86:051106-051108.
[26] Chen D, Wang Y, Zheng K, Guo T, Yu Y, Huang P. Bright upconversion white light emission in transparent glass ceramic embedding Tm3+/Er3+/Yb3+:β-YF3 nanocrystals[J].Appl. Phys. Lett. 2007,91:251903
[27] Zhang H X, Kam C H, Zhou Y, Han X Q, Buddhudu S, and Lam Y L. Visible up-conversion luminescence in Er3+: BaTiO3 nanocrystals [J]. Opt. Mater., 2000, 15:47-50.
[28] Tao Y, Zhao G, Zhang W, Xia S. Combustion synthesis and photoluminescence of nanocrystslline Y2O3: Eu3+ phosphors[J]. Mater. Res. Bull., 1997, 32:501-506.
[29] Riwotzki K, Haase M. Wet-Chemical Synthesis of Doped ColloidalNanoparicles: YVO4: Ln (Ln=Eu, Sm, Dy) [J]. J. Phys. Chem. B, 1998, 102:10129-10135.
[30] Li Y P, Zhang, J H , Zhang X, Luo Y S, Near-Infrared to Visible Upconversion in Er3+ and Yb3+ Codoped Lu2O3 Nanocrystals:Enhanced Red Color Upconversion and Three-Photon Process in Green Color Upconversion [J]. J. Phys. Chem.C,2009,doi: 10.1021/jp810275t
[31] Patra A, Friend C S, Kapoor R, Prasad P N. Effect of crystal nature on upconversion luminescence in Er3+:ZrO2 nanocrystals[J]. Appl. Phys.Lett.,2003,83(2):283-286
[32] John A C, Vetrone F, Boyer C J. Adolfo Speghini and Marco Bettinelli. Ehancement of Red Emission(4F9/2→4I15/2) via Upconversion in Bulk and Nanocrystalline Cubic Y2O3:Er3+[J].J. Phys. Chem. B, 2002, 106:1181-1187
[33] Diaz-Torres L A, De la Rosa E, Salas P, Desirena H. Enhanced cooperative absorption and upconversion in Yb3+ doped YAG nanophosphors[J]. Opt. Mater.2005,27(7):1305-1310
[34] Rafik N, Vetrone F, Mahalingam V, Cuccia L A, A John. Capobianco Controlled Synthesis and Water Dispersibility of Hexagonal Phase NaGdF4:Ho3+/Yb3+ Nanoparticles[J].Chem. Mater., 2009, 21 (4):717-723
[35] Wang L Y, Li Y D. Na(Y1.5Na0.5)F6 Single-Crystal Nanorods as Multicolor Luminescent Materials[J]. Nano Lett., 2006, 6:1645-1649.
[36]张军杰,段忠超,何冬兵等.频率上转换掺稀土氧氟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.
[37] Dantelle G, Mortier M, Vivien D. Nucleation efficiency of erbium and ytterbium fluorides in transparent oxyfluoride glass-ceramics[J]. J. Mater. Res., 2005, 20(2): 472-481.
[38] Zhao D L, Qiao X S, Fan X P, et al. Local vibration around rare earth ions in SiO2–PbF2 glass and glass ceramics using Eu3+ probe[J]. Physica B: Condens. Matter, 2007, 395: 10-15.
[39]陈晓波,李美仙,郝昭等. 966 nm半导体激光激发下Er3+/Yb3+:ZBLAN玻璃的上转换特征饱和现象[J].光谱学与光谱分析, 2001, 21(3): 271-274.
[40] Zellmer H, Plamann K, Huber G,et al. Visible double-clad upconversion fiber laser [J]. Electronics Letters, 1998, 34(16): 565-567.
[41] Sandrock T, Scheife H, et al. High-power continuous wave upconversion fiber laser at room temperature [J]. Opt. Lett., 1997, 22(11): 808-810.
[42] Wang J, Qiao X S, Fan X P, et al. Preparation and luminescence of Er3+ doped oxyfluoride glass ceramics containing LaF3 nanocrystals[J]. J. Rare Earths, 2006, 24: 67-71.
[43] Zhang S J, Cheng Z X. A new nonlinear optical crystal GdCa4O(BO3)3 [J]. Chin. Phys. Lett., 1999, 16(3): 184-186.
[44] Hemmila I, Dakubu S, Mukkala V M, Siitari H, Lovgren T. Europium as a label in time-resolved immunofluorometric assays[J].Anal. Biochem., 1984, 137:335-343
[45] Mukkala V M, Mikola H, Hemmila I. The synthesis and use of activated N-benzyl derivatives of diethyllenetriaminetetraacetic acid: alternative reagents for labeling of antibodies with metal-ions. Anal. Biochem., 1989, 176:319-324.
[46] Xu Y. Lanthanide fluorescence assay for bioaffinity compounds [J]. PCT Int Application No. 1992, 92:16,840.
[47]赵永凯,周蕾,黄惠杰.基于上转换发光技术的生物传感器及其应用[J].光学学报,2005, 25(6): 841-847.
[48] Rufaihah Abdul Jalil, ZhangY. Biocompatibility of silica coated NaYF4 upconversion fluorescent nanocrystals[J].Biomaterials 2008,29:4122–4128
[49] Yi G S, H. C. Lu, S. Y. Zhao, G. Yue, W. J. Yang, D. P. Chen, and L. H. Guo, Synthesis, Characterization, and Biological Application of Size-Controlled Nanocrystalline NaYF4:Yb,Er Infrared-to-Visible Up-Conversion Phosphors [J].Nano Lett. 2004, 4: 2191.
[50] Hai X, Tan M, Wang G, Ye Z, Yuan J, Kazuko Matsumoto, Preparation and a Time-Resolved Fluorometric Application of New Europium Fluorescence Nanoparticle, Analytical Sciences, 2004, 20:245-246
[51] Chen G Y, Somesfalean G, Liu Y, Zhang Z G, Sun Q, Wang F P. Two-color upconversion in rare-earth-ion-doped ZrO2 nanocrystals [J]. Appl. Phy. Lett. 2006,89:163105.
[52] J.E.C. da Silva, G.F. de Sa′, P.A. Santa-Cruz White light simulation by up-conversion in fluoride glass host [J]. Journal of Alloys and Compounds 2002,344:260–263
[53] Smet P F, Korthout K, Van Haecke J E, Poelman D. Using rare earth doped thiosilicate phosphors in white light emitting LEDs: Towards low colour temperature and high colour rendering [J]Materials Science and Engineering B ,2008,146:264-268
[54] Tan M, Ye Z, Wang G, Yuan J. Preparation and Time-Resolved Fluorometric Application of the Luminescent Europium Nanoparticles. Chemistry of Materials, 2004, 16:2494-2498.
[55] Dijken A, Meulenkamp E, Vanmaekelbergh A D, Meijerink A. The Kinetics of the Radiative and Nonradiative Processes in Nanocrystalline ZnO Particles upon Photoexcitation[J]. J. Phys. Chem. B, 2000, 104:1715-1723.
[56] Judd B R. Optical Absorption Intensities of Rare-Earth Ions Optical absorption intensities of rare-earth ions [J]. Phys. Rev., 1962, 127:750-761.
[57] Ofelt G S. Intensities of Crystal Spectra of Rare-Earth Ions Intensities of crytal spectra of rare earth ions [J]. J. Chem. Phys., 1962, 37(3):511-520.
[58] Bian J M, Li X M, Chen L D, Yao Q. Properties of undoped n-type ZnO film and N-In codoped p-type ZnO film deposited by ultrasonic spray pyrolysis[J]. Chem. Phys. Lett., 2004, 393(3):256-259.
[59] Brown M R, Cox A F J, Shand W A, Willianms J M. The Photoluminescence of Er3+-Doped ZnO[J]. Adv. Qunantum Electronics, 1974, 2:69-71.
[60] Wang X, Kong X, Shan G, Yu Y, Sun Y, Feng L, et al. Luminescence Spectroscopy and Visible Upconversion Properties of Er3+ in ZnO Nanocrystals[J]. J. Phys. Chem. B, 2004, 108:18408-18413
[61] Wang X, Kong X, Yu Y, Sun Y, Zhang H. Effect of Annealing on Upconversion Luminescence of ZnO:Er3+ Nanocrystals and High Thermal Sensitivity [J].J.Phys.Chem.C, 2007, 111(41):15119-15124
[62] Chen G. Y, Liu H C, Somesfalean G, Zhang Z G, Sun Q, et al. Enhancement of the upconversion radiation in Y2O3:Er3+ nanocrystals by codoping with Li+ ions Appl. Phys. Lett., 2008, 92:113114.
[63] Han H L, Yang L W, Liu Y X, Zhang Y Y, Yang Q B. Up-conversion luminescence switching in Er3+-containing ZnO nanoparticles through Li+ co-doping Opt. Mater [J]. 2008, 31:338
[64] Sun Y J, Chen Y, Tian L J, Yu Y, Kong X G, Zeng Q H, Zhang Y L, Zhang H, Morphology-dependent upconversion luminescence of ZnO:Er3+ nanocrystals[J].J. Lumin., 2008, 128:15.
[65] Yang L W, Wu X L, Huang G S, Qiu T, Yang Y M. In situ synthesis of Mn-doped ZnO multileg nanostructures and Mn-related Raman vibration [J]. J. Appl. Phys., 2005, 97:014308.
[66] Auzel F. Upconversion and Anti-Stokes Processes with f and d Ions in Solids [J].Chem. Rev., 2004, 104:139.
[67] Zhou Z, Komori K, Yoshino M, Morinaga M, et al. Takeda Y, Enhanced 1.54μm photoluminescence from Er-containing ZnO through nitrogen doping Appl. Phys. Lett. , 2005, 86:041107.
[68] Zhou Z, Komori K, Ayukawa T, Yukawa H, Morinaga M, N, Koizumi A, Takeda Y. Li-and Er-codoped ZnO with enhanced 1.54μm photoemission[J].Appl. Phys. Lett. , 2005, 87:091109.
[69] Wu X L, Mei Y F, Siu G G, Wong K L, Moulding K, Stokes M J, Fu C L, X.M. Bao,Spherical Growth and Surface-Quasifree Vibrations of Si Nanocrystallites in Er-Doped Si Nanostructures [J].Phys. Rev. Lett. 2001,86, 3000.
[70] Kanoun A, Jaba N, Brenier A. Time-resolved up-converted luminescence in Er3+-doped TeO2–ZnO glass [J].Opt. Mater, 2004, 26:79.
[71] Wang X, Kong X G, Shan G Y, Yu Y, Sun Y J, Feng L Y, Chao K F, Lu S Z, Li Y J, Luminescence Spectroscopy and Visible Upconversion Properties of Er3+ in ZnO Nanocrystals[J].J. Phys. Chem.B,2004, 108:18408.
[72] Tsuboi T. Upconversion emission in Er3+/Yb3+-codoped YVO4 crystals [J].Phys. Rev. B, 2000, 62:4200.
[73] Bai Y F, Wang Y X, Yang K, Zhang X R, Song Y L, Enhanced upconverted photoluminescence in Er3+ and Yb3+ codoped ZnO nanocrystals with and without Li+ ions [J]. J]. Opt. Commun. 2008, 281: 5448
[74] Downing E, Hesselink L, Ralston J, Macfarlance R. A three-color, solid-state, three-dimensional display [J]. Science, 1996, 273:1185.
[75] ?ahoz F, Martín I R, Calvilla-QuinteroJ M, Ultraviolet and white photon avalanche upconversion in Ho3+-doped nanophase glass ceramics [J]. Appl. Phys. Lett. , 2005, 86: 051106.
[76] Chen G Y, Liu Y, Zhang Y G, Somesfalean G, Zhang Z G, et al , Bright white upconversion luminescence in rare-earth-ion-doped Y2O3 nanocrystals[J]. Appl. Phys. Lett. , 2007, 91:133103.
[77] Shalav A. Richards B S, Trupke T, Kramer K W, Güdel H U, High mobility transparent thin-film transistors with amorphous zinc tin oxide channel layer [J].Appl. Phys. Lett. , 2005, 86, 13503.
[78] Suyver J F, Grimm J, Van Veen M K, Biner D, Kramer K W, Güdel H U, Upconversion spectroscopy and properties of NaYF4 doped with Er3+, Tm3+ and/or Yb3+ [J].J. Lumin. , 2006, 117:1.
[79] Suyver J F, Grimm J, Kramer K W, Güdel H U, J. Lumin. Highly efficient near-infrared to visible up-conversion process in NaYF4:Er3+, Yb3+ [J]. , 2005,114, 53.
[80] Zeng J H, Su J, Li Y D, Synthesis and Upconversion Luminescence of Hexagonal-Phase NaYF4: Yb, Er3+ Phosphors of Controlled Size and Morphology [J].Adv. Mater. , 2005, 17:2119.
[81] Mai H X, Zhang Y W, Si Z R. Yan G, Sun L D, You L P, Yan C H. High-Quality Sodium Rare-Earth Fluoride Nanocrystals: Controlled Synthesis and Optical Properties [J].J. Am. Chem. Soc.,2006, 128:6426.
[82] Heer S, Kompe K, Gudel H U, et al., Highly Efficient Multicolour Upconversion Emission in Transparent Colloids of Lanthanide-Doped NaYF4 Nanocrystals [J].Adv. Mater.2004,16 (23-24):2 102
[83] Wei Y, Lu F Q, Zhang X R, Chen D P. Synthesis and characterization of efficient near-infrared upconversion Yb3+ and Tm3+ codoped NaYF4 nanocrystal reporter [J]. J. Alloys Compd., 2007, 427:333-340.
[84] Nakazaw E, Shionoya S. Cooperative Luminescence in YbPO4 [J].Phys. Rev. Lett.25, 1710 (1970).
[85] Maciel G S, Biswas A, Prasad P N. Infrared-to-visible Eu3+ energy upconversion due to cooperative energy transfer from an Yb3+ ion pair in a sol–gel processed multi-component silica glass [J]. Opt. Commun. , 2000,178, 65.
[86] Patra A, Saha A, Alencar R C. Rakov N, Maciel G S. Blue upconversion emission of Tm3+–Yb3+ in ZrO2 nanocrystals: Role of Yb3+ ions[J]. Chem. Phys. Lett., 2005, 407: 477.
[87] Pandozzi F, Vetrone F, Boyer J C, Naccache R. et al. A Spectroscopic Analysis of Blue and Ultraviolet Upconverted Emissions from Gd3Ga5O12:Tm3+, Yb3+ Nanocrystals [J].J. Phys. Chem. B 2005, 109:17400.
[88] Y.Y.Zhang, L.W.Yang, H.L.Han, J.X.Zhong. Excitation power controlled luminescence switching in Yb3+-Tm3+ co-doped hexagonal NaYF4 nanorods[J]. OpticalCommunications, 2009,doi:10.1016
[89] Xiao S. Yang X, Ding J W, Yan X H, Up-conversion in Yb3+/Tm3+ Co-Doped Lutetium Fluoride Prepared by a Combustion-Fluroization Method [J].J. Phys. Chem. C ,2007,111: 8161.
[90] Auzel F. Multiphonon-assisted anti-Stokes and Stokes fluorescence of triply ionized rare-earth ions [J].Phys. Rev. B, 1976, 13:2809.
[91] Reddy B R, Venkateswarlu P. Infrared to visible energy upconversion in Er3+-doped oxide glass[J]. Appl. Phys. Lett., 1993, 64(11):1327-1329.
[92] Dexter D J. A Theory of Sensitized Luminescence in Solids [J].J. Chem. Phys., 1953, 21: 836.
[93] Chen C Y, Petrin R R, Yeh D C, Sibley W A. Concentration-dependent energy-transfer processes inEr3+-and Tm3+-doped heavy-metal fluoride glass [J].Opt. lett.1989, 14:432.
[94] Capobianco J A, Vetrone F, Boyer J C, Bettinelli M. Visible of Er3+ doped nanocrystalline and bulls Lu2O3[J].Opt. Mater. 2002, 259-268
[95] Li C X, Zhang C M, Lin J.β-NaYF4 andβ-NaYF4:Eu3+. Microstructures: Morphology Control and Tunable Luminescence Properties [J]. J. Phys. Chem. C 2009, 113:2332
[96] Ghosh P, Patra A.Influence of Crystal Phase and Excitation Wavelength on Luminescence Properties of Eu3+-Doped Sodium Yttrium Fluoride Nanocrystals [J]. J. Phys. Chem. C 2008, 112,:19283
[97] Traina C A, Dennes T J, Schwartz J. A Modular Monolayer Coating Enables Cell Targeting by Luminescent Yttria Nanoparticles [J] Bioconjugate Chem.2009, doi:10.1021/bc800551x