Abstract

In vitro and in vivo bioimaging, Yb/Tm doped fluoride nanocrystals (NCs) as nanoprobes have attracted much attention due to their near infrared (NIR) upconversion (UC) emission at 800 nm under NIR 980 nm excitation. Our paper presents a simple and general method which can further improve the intensity of NIR 800 nm emission of Tm3+ through adding Ho3+ as the second sensitizer of Tm3+ in Yb/Tm doped NaYF4 nanorods. The intensity of the NIR 800 nm emission is demonstrated to increase by up to 3 times along with the adding of Ho3+. Experimental data illustrates that the sensitizations of Tm3+ by both Yb3+ and Ho3+ provide a more efficient energy transfer (ET) route for intense 800 nm emission than that by Yb3+ alone.

© 2012 OSA

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  1. M. J. Weber, “Multiphonon relaxation of Rare-Earth Ions in Yttrium Orthoaluminate,” Phys. Rev. B 8(1), 54–64 (1973).
    [CrossRef]
  2. R. X. Yan and Y. D. Li, “Down/Up conversion in Ln3+-doped YF3 nanocrystals,” Adv. Funct. Mater. 15(5), 763–770 (2005).
    [CrossRef]
  3. V. Mahalingam, F. Vetrone, R. Naccache, A. Speghini, and J. A. Capobianco, “Colloidal Tm3+/Yb3+-Doped LiYF4 Nanocrystals: Multiple Luminescence spanning the UV to NIR Regions via low-energy excitation,” Adv. Mater. (Deerfield Beach Fla.) 21(40), 4025–4028 (2009).
    [CrossRef]
  4. D. Chen, Y. Yu, F. Huang, P. Huang, A. Yang, and Y. Wang, “Modifying the Size and Shape of Monodisperse Bifunctional Alkaline-Earth Fluoride Nanocrystals through Lanthanide Doping,” J. Am. Chem. Soc. 132(29), 9976–9978 (2010).
    [CrossRef] [PubMed]
  5. P. Huang, F. Liu, D. Chen, Y. Wang, and Y. Yu, “Highly efficient near-infrared to visible upconversion luminescence in transparent glass ceramics containing Yb3+/Er3+:NaYF4 nanocrystals,” Phys. Status Solidi A 205(7), 1680–1684 (2008).
    [CrossRef]
  6. F. Liu, E. Ma, D. Chen, Y. Yu, and Y. Wang, “Tunable Red-Green Upconversion Luminescence in Novel Transparent Glass Ceramics Containing Er: NaYF4 Nanocrystals,” J. Phys. Chem. B 110(42), 20843–20846 (2006).
    [CrossRef] [PubMed]
  7. L. Xiong, T. Yang, Y. Yang, C. Xu, and F. Li, “Long-term in vivo biodistribution imaging and toxicity of polyacrylic acid-coated upconversion nanophosphors,” Biomaterials 31(27), 7078–7085 (2010).
    [CrossRef] [PubMed]
  8. L. F. Johnson and H. J. Guggenheim, “Infrared-pumped visible laser,” Appl. Phys. Lett. 19(2), 44–47 (1971).
    [CrossRef]
  9. S. F. Lim, R. Riehn, W. S. Ryu, N. Khanarian, C. Tung, D. Tank, and R. H. Austin, “In vivo and scanning electron microscopy imaging of upconverting Nanophosphors in Caenorhabditis elegans,” Nano Lett. 6(2), 169–174 (2006).
    [CrossRef]
  10. L. Y. Wang, R. X. Yan, Z. Huo, L. Wang, J. H. Zeng, H. Bao, X. Wang, Q. Peng, and Y. D. Li, “Fluorescence resonant energy transfer biosensor based on upconversion-luminescent nanoparticles,” Angew. Chem. Int. Ed. Engl. 44(37), 6054–6057 (2005).
    [CrossRef] [PubMed]
  11. M. Wang, C. C. Mi, W. X. Wang, C. H. Liu, Y. F. Wu, Z.-R. Xu, C. B. Mao, and S. K. Xu, “Immunolabeling and NIR-excited fluorescent imaging of HeLa cells by using NaYF4:Yb,Er upconversion nanoparticles,” ACS Nano 3(6), 1580–1586 (2009).
    [CrossRef] [PubMed]
  12. J. Zhou, M. Yu, Y. Sun, X. Zhang, X. Zhu, Z. Wu, D. Wu, and F. Li, “Fluorine-18-labeled Gd3+/Yb3+/Er3+ co-doped NaYF4 nanophosphors for multimodality PET/MR/UCL imaging,” Biomaterials 32(4), 1148–1156 (2011).
    [CrossRef] [PubMed]
  13. L. Y. Wang and Y. D. Li, “Green upconversion nanocrystals for DNA detection,” Chem. Commun. (Camb.) 24(24), 2557–2559 (2006).
    [CrossRef] [PubMed]
  14. D. K. Chatterjee, A. J. Rufaihah, and Y. Zhang, “Upconversion fluorescence imaging of cells and small animals using lanthanide doped nanocrystals,” Biomaterials 29(7), 937–943 (2008).
    [CrossRef] [PubMed]
  15. S. Jeong, N. Won, J. Lee, J. Bang, J. Yoo, S. G. Kim, J. A. Chang, J. Kim, and S. Kim, “Multiplexed near-infrared in vivo imaging complementarily using quantum dots and upconverting NaYF4:Yb3+,Tm3+ nanoparticles,” Chem. Commun. (Camb.) 47(28), 8022–8024 (2011).
    [CrossRef] [PubMed]
  16. G. Chen, T. Y. Ohulchanskyy, W. C. Law, H. Ågren, and P. N. Prasad, “Monodisperse NaYbF4:Tm3+/NaGdF4 core/shell nanocrystals with near-infrared to near-infrared upconversion photoluminescence and magnetic resonance properties,” Nanoscale 3(5), 2003–2008 (2011).
    [CrossRef] [PubMed]
  17. J. C. Zhou, Z. L. Yang, W. Dong, R. J. Tang, L. D. Sun, and C. H. Yan, “Bioimaging and toxicity assessments of near-infrared upconversion luminescent NaYF4:Yb,Tm nanocrystals,” Biomaterials 32(34), 9059–9067 (2011).
    [CrossRef] [PubMed]
  18. G. Chen, T. Y. Ohulchanskyy, R. Kumar, H. Ågren, and P. N. Prasad, “Ultrasmall monodisperse NaYF4:Yb3+/Tm3+ nanocrystals with enhanced near-infrared to near-infrared upconversion photoluminescence,” ACS Nano 4(6), 3163–3168 (2010).
    [CrossRef] [PubMed]
  19. L. L. Wang, C. Y. Cao, X. J. Xue, D. Zhao, D. S. Zhang, K. Z. Zheng, N. Liu, F. Shi, C. F. He, and W. P. Qin, “Effect of crystal structure and ions concentration on luminescence in Yb3+ and Tm3+ codoped fluoride microcrystals,” J. Fluor. Chem. 130(11), 1059–1062 (2009).
    [CrossRef]
  20. J. C. Boyer, L. A. Cuccia, and J. A. Capobianco, “Synthesis of colloidal upconverting NaYF4: Er3+/Yb3+ and Tm3+/Yb3+ monodisperse nanocrystals,” Nano Lett. 7(3), 847–852 (2007).
    [CrossRef] [PubMed]
  21. G. F. Wang, W. P. Qin, J. S. Zhang, L. L. Wang, G. D. Wei, P. F. Zhu, and R. J. Kim, “Controlled synthesis and luminescence properties from cubic to hexagonal NaYF4:Ln3+ (Ln = Eu and Yb/Tm) microcrystals,” J. Alloy. Comp. 475(1-2), 452–455 (2009).
    [CrossRef]
  22. J. H. Zeng, J. Su, Z. H. Li, R. X. Yan, and Y. D. Li, “Synthesis and Upconversion Luminescence of Hexagonal-Phase NaYF4:Yb, Er3+ Phosphors of controlled size and morphology,” Adv. Mater. (Deerfield Beach Fla.) 17(17), 2119–2123 (2005).
    [CrossRef]
  23. C. Liu, H. Wang, X. Li, and D. Chen, “Monodisperse, size-tunable and highly efficient beta-NaYF4:Yb,Er(Tm) up-conversion luminescent nanospheres: controllable synthesis and their surface modifications,” J. Mater. Chem. 19(21), 3546–3553 (2009).
    [CrossRef]
  24. L. L. Wang, H. Chen, D. S. Zhang, D. Zhao, and W. P. Qin, “Dual-mode luminescence from lanthanide tri-doped NaYF4 nanocrystals,” Mater. Lett. 65(3), 504–506 (2011).
    [CrossRef]
  25. C. Li, S. Xu, R. Ye, D. Deng, Y. Hua, S. Zhao, and S. Zhuang, “White up-conversion emission in Ho3+/Tm3+/Yb3+ tri-doped glass ceramics embedding BaF2 nanocrystals,” Physica B 406(9), 1698–1701 (2011).
    [CrossRef]
  26. D. Kasprowicz, M. G. Brik, A. Majchrowski, E. Michalski, and P. Gluchowski, “Up-conversion emission in triply-doped Ho3+/Yb3+/Tm3+ KGd(WO4)2 single crystals,” Opt. Commun. 284(12), 2895–2899 (2011).
    [CrossRef]
  27. C. Sun, F. Yang, T. Cao, Z. You, Y. Wang, J. Li, Z. Zhu, and C. Tu, “Infrared spectroscopic properties of Tm3+, Ho3+:NaY(WO4)2 single crystals,” J. Alloy. Comp. 509(25), 6987–6993 (2011).
    [CrossRef]
  28. V. Mahalingam, R. Naccache, F. Vetrone, and J. A. Capobianco, “Enhancing upconverted white light in Tm3+/Yb3+/Ho3+-doped GdVO4 nanocrystals via incorporation of Li+ ions,” Opt. Express 20(1), 111–119 (2012).
    [CrossRef] [PubMed]
  29. P. Li, Q. Peng, and Y. D. Li, “Dual-mode luminescent colloidal spheres from monodisperse rare-earth fluoride nanocrystals,” Adv. Mater. (Deerfield Beach Fla.) 21(19), 1945–1948 (2009).
    [CrossRef]
  30. G. Y. Chen, C. H. Yang, B. Aghahadi, H. J. Liang, Y. Liu, L. Li, and Z. G. Zhang, “Ultraviolet-blue upconversion emissions of Ho3+ ions,” J. Opt. Soc. Am. B 27(6), 1158–1164 (2010).
    [CrossRef]
  31. G. F. Wang, W. P. Qin, L. L. Wang, G. D. Wei, P. F. Zhu, and R. J. Kim, “Intense ultraviolet upconversion luminescence from hexagonal NaYF4:Yb3+/Tm3+ microcrystals,” Opt. Express 16(16), 11907–11914 (2008).
    [CrossRef] [PubMed]
  32. K. Z. Zheng, D. S. Zhang, D. Zhao, N. Liu, F. Shi, and W. P. Qin, “Bright white upconversion emission from Yb3+, Er3+, and Tm3+-codoped Gd2O3 nanotubes,” Phys. Chem. Chem. Phys. 12(27), 7620–7625 (2010).
    [CrossRef] [PubMed]
  33. M. Pollnau, D. R. Gamelin, S. R. Luthi, H. U. Gudel, and M. P. Hehlen, “Power dependence of upconversion luminescence in lanthanide and transition-metal-ion systems,” Phys. Rev. B 61(5), 3337–3346 (2000).
    [CrossRef]

2012 (1)

2011 (8)

L. L. Wang, H. Chen, D. S. Zhang, D. Zhao, and W. P. Qin, “Dual-mode luminescence from lanthanide tri-doped NaYF4 nanocrystals,” Mater. Lett. 65(3), 504–506 (2011).
[CrossRef]

C. Li, S. Xu, R. Ye, D. Deng, Y. Hua, S. Zhao, and S. Zhuang, “White up-conversion emission in Ho3+/Tm3+/Yb3+ tri-doped glass ceramics embedding BaF2 nanocrystals,” Physica B 406(9), 1698–1701 (2011).
[CrossRef]

D. Kasprowicz, M. G. Brik, A. Majchrowski, E. Michalski, and P. Gluchowski, “Up-conversion emission in triply-doped Ho3+/Yb3+/Tm3+ KGd(WO4)2 single crystals,” Opt. Commun. 284(12), 2895–2899 (2011).
[CrossRef]

C. Sun, F. Yang, T. Cao, Z. You, Y. Wang, J. Li, Z. Zhu, and C. Tu, “Infrared spectroscopic properties of Tm3+, Ho3+:NaY(WO4)2 single crystals,” J. Alloy. Comp. 509(25), 6987–6993 (2011).
[CrossRef]

J. Zhou, M. Yu, Y. Sun, X. Zhang, X. Zhu, Z. Wu, D. Wu, and F. Li, “Fluorine-18-labeled Gd3+/Yb3+/Er3+ co-doped NaYF4 nanophosphors for multimodality PET/MR/UCL imaging,” Biomaterials 32(4), 1148–1156 (2011).
[CrossRef] [PubMed]

S. Jeong, N. Won, J. Lee, J. Bang, J. Yoo, S. G. Kim, J. A. Chang, J. Kim, and S. Kim, “Multiplexed near-infrared in vivo imaging complementarily using quantum dots and upconverting NaYF4:Yb3+,Tm3+ nanoparticles,” Chem. Commun. (Camb.) 47(28), 8022–8024 (2011).
[CrossRef] [PubMed]

G. Chen, T. Y. Ohulchanskyy, W. C. Law, H. Ågren, and P. N. Prasad, “Monodisperse NaYbF4:Tm3+/NaGdF4 core/shell nanocrystals with near-infrared to near-infrared upconversion photoluminescence and magnetic resonance properties,” Nanoscale 3(5), 2003–2008 (2011).
[CrossRef] [PubMed]

J. C. Zhou, Z. L. Yang, W. Dong, R. J. Tang, L. D. Sun, and C. H. Yan, “Bioimaging and toxicity assessments of near-infrared upconversion luminescent NaYF4:Yb,Tm nanocrystals,” Biomaterials 32(34), 9059–9067 (2011).
[CrossRef] [PubMed]

2010 (5)

G. Chen, T. Y. Ohulchanskyy, R. Kumar, H. Ågren, and P. N. Prasad, “Ultrasmall monodisperse NaYF4:Yb3+/Tm3+ nanocrystals with enhanced near-infrared to near-infrared upconversion photoluminescence,” ACS Nano 4(6), 3163–3168 (2010).
[CrossRef] [PubMed]

D. Chen, Y. Yu, F. Huang, P. Huang, A. Yang, and Y. Wang, “Modifying the Size and Shape of Monodisperse Bifunctional Alkaline-Earth Fluoride Nanocrystals through Lanthanide Doping,” J. Am. Chem. Soc. 132(29), 9976–9978 (2010).
[CrossRef] [PubMed]

L. Xiong, T. Yang, Y. Yang, C. Xu, and F. Li, “Long-term in vivo biodistribution imaging and toxicity of polyacrylic acid-coated upconversion nanophosphors,” Biomaterials 31(27), 7078–7085 (2010).
[CrossRef] [PubMed]

G. Y. Chen, C. H. Yang, B. Aghahadi, H. J. Liang, Y. Liu, L. Li, and Z. G. Zhang, “Ultraviolet-blue upconversion emissions of Ho3+ ions,” J. Opt. Soc. Am. B 27(6), 1158–1164 (2010).
[CrossRef]

K. Z. Zheng, D. S. Zhang, D. Zhao, N. Liu, F. Shi, and W. P. Qin, “Bright white upconversion emission from Yb3+, Er3+, and Tm3+-codoped Gd2O3 nanotubes,” Phys. Chem. Chem. Phys. 12(27), 7620–7625 (2010).
[CrossRef] [PubMed]

2009 (6)

P. Li, Q. Peng, and Y. D. Li, “Dual-mode luminescent colloidal spheres from monodisperse rare-earth fluoride nanocrystals,” Adv. Mater. (Deerfield Beach Fla.) 21(19), 1945–1948 (2009).
[CrossRef]

G. F. Wang, W. P. Qin, J. S. Zhang, L. L. Wang, G. D. Wei, P. F. Zhu, and R. J. Kim, “Controlled synthesis and luminescence properties from cubic to hexagonal NaYF4:Ln3+ (Ln = Eu and Yb/Tm) microcrystals,” J. Alloy. Comp. 475(1-2), 452–455 (2009).
[CrossRef]

C. Liu, H. Wang, X. Li, and D. Chen, “Monodisperse, size-tunable and highly efficient beta-NaYF4:Yb,Er(Tm) up-conversion luminescent nanospheres: controllable synthesis and their surface modifications,” J. Mater. Chem. 19(21), 3546–3553 (2009).
[CrossRef]

L. L. Wang, C. Y. Cao, X. J. Xue, D. Zhao, D. S. Zhang, K. Z. Zheng, N. Liu, F. Shi, C. F. He, and W. P. Qin, “Effect of crystal structure and ions concentration on luminescence in Yb3+ and Tm3+ codoped fluoride microcrystals,” J. Fluor. Chem. 130(11), 1059–1062 (2009).
[CrossRef]

V. Mahalingam, F. Vetrone, R. Naccache, A. Speghini, and J. A. Capobianco, “Colloidal Tm3+/Yb3+-Doped LiYF4 Nanocrystals: Multiple Luminescence spanning the UV to NIR Regions via low-energy excitation,” Adv. Mater. (Deerfield Beach Fla.) 21(40), 4025–4028 (2009).
[CrossRef]

M. Wang, C. C. Mi, W. X. Wang, C. H. Liu, Y. F. Wu, Z.-R. Xu, C. B. Mao, and S. K. Xu, “Immunolabeling and NIR-excited fluorescent imaging of HeLa cells by using NaYF4:Yb,Er upconversion nanoparticles,” ACS Nano 3(6), 1580–1586 (2009).
[CrossRef] [PubMed]

2008 (3)

P. Huang, F. Liu, D. Chen, Y. Wang, and Y. Yu, “Highly efficient near-infrared to visible upconversion luminescence in transparent glass ceramics containing Yb3+/Er3+:NaYF4 nanocrystals,” Phys. Status Solidi A 205(7), 1680–1684 (2008).
[CrossRef]

D. K. Chatterjee, A. J. Rufaihah, and Y. Zhang, “Upconversion fluorescence imaging of cells and small animals using lanthanide doped nanocrystals,” Biomaterials 29(7), 937–943 (2008).
[CrossRef] [PubMed]

G. F. Wang, W. P. Qin, L. L. Wang, G. D. Wei, P. F. Zhu, and R. J. Kim, “Intense ultraviolet upconversion luminescence from hexagonal NaYF4:Yb3+/Tm3+ microcrystals,” Opt. Express 16(16), 11907–11914 (2008).
[CrossRef] [PubMed]

2007 (1)

J. C. Boyer, L. A. Cuccia, and J. A. Capobianco, “Synthesis of colloidal upconverting NaYF4: Er3+/Yb3+ and Tm3+/Yb3+ monodisperse nanocrystals,” Nano Lett. 7(3), 847–852 (2007).
[CrossRef] [PubMed]

2006 (3)

L. Y. Wang and Y. D. Li, “Green upconversion nanocrystals for DNA detection,” Chem. Commun. (Camb.) 24(24), 2557–2559 (2006).
[CrossRef] [PubMed]

F. Liu, E. Ma, D. Chen, Y. Yu, and Y. Wang, “Tunable Red-Green Upconversion Luminescence in Novel Transparent Glass Ceramics Containing Er: NaYF4 Nanocrystals,” J. Phys. Chem. B 110(42), 20843–20846 (2006).
[CrossRef] [PubMed]

S. F. Lim, R. Riehn, W. S. Ryu, N. Khanarian, C. Tung, D. Tank, and R. H. Austin, “In vivo and scanning electron microscopy imaging of upconverting Nanophosphors in Caenorhabditis elegans,” Nano Lett. 6(2), 169–174 (2006).
[CrossRef]

2005 (3)

L. Y. Wang, R. X. Yan, Z. Huo, L. Wang, J. H. Zeng, H. Bao, X. Wang, Q. Peng, and Y. D. Li, “Fluorescence resonant energy transfer biosensor based on upconversion-luminescent nanoparticles,” Angew. Chem. Int. Ed. Engl. 44(37), 6054–6057 (2005).
[CrossRef] [PubMed]

R. X. Yan and Y. D. Li, “Down/Up conversion in Ln3+-doped YF3 nanocrystals,” Adv. Funct. Mater. 15(5), 763–770 (2005).
[CrossRef]

J. H. Zeng, J. Su, Z. H. Li, R. X. Yan, and Y. D. Li, “Synthesis and Upconversion Luminescence of Hexagonal-Phase NaYF4:Yb, Er3+ Phosphors of controlled size and morphology,” Adv. Mater. (Deerfield Beach Fla.) 17(17), 2119–2123 (2005).
[CrossRef]

2000 (1)

M. Pollnau, D. R. Gamelin, S. R. Luthi, H. U. Gudel, and M. P. Hehlen, “Power dependence of upconversion luminescence in lanthanide and transition-metal-ion systems,” Phys. Rev. B 61(5), 3337–3346 (2000).
[CrossRef]

1973 (1)

M. J. Weber, “Multiphonon relaxation of Rare-Earth Ions in Yttrium Orthoaluminate,” Phys. Rev. B 8(1), 54–64 (1973).
[CrossRef]

1971 (1)

L. F. Johnson and H. J. Guggenheim, “Infrared-pumped visible laser,” Appl. Phys. Lett. 19(2), 44–47 (1971).
[CrossRef]

Aghahadi, B.

Ågren, H.

G. Chen, T. Y. Ohulchanskyy, W. C. Law, H. Ågren, and P. N. Prasad, “Monodisperse NaYbF4:Tm3+/NaGdF4 core/shell nanocrystals with near-infrared to near-infrared upconversion photoluminescence and magnetic resonance properties,” Nanoscale 3(5), 2003–2008 (2011).
[CrossRef] [PubMed]

G. Chen, T. Y. Ohulchanskyy, R. Kumar, H. Ågren, and P. N. Prasad, “Ultrasmall monodisperse NaYF4:Yb3+/Tm3+ nanocrystals with enhanced near-infrared to near-infrared upconversion photoluminescence,” ACS Nano 4(6), 3163–3168 (2010).
[CrossRef] [PubMed]

Austin, R. H.

S. F. Lim, R. Riehn, W. S. Ryu, N. Khanarian, C. Tung, D. Tank, and R. H. Austin, “In vivo and scanning electron microscopy imaging of upconverting Nanophosphors in Caenorhabditis elegans,” Nano Lett. 6(2), 169–174 (2006).
[CrossRef]

Bang, J.

S. Jeong, N. Won, J. Lee, J. Bang, J. Yoo, S. G. Kim, J. A. Chang, J. Kim, and S. Kim, “Multiplexed near-infrared in vivo imaging complementarily using quantum dots and upconverting NaYF4:Yb3+,Tm3+ nanoparticles,” Chem. Commun. (Camb.) 47(28), 8022–8024 (2011).
[CrossRef] [PubMed]

Bao, H.

L. Y. Wang, R. X. Yan, Z. Huo, L. Wang, J. H. Zeng, H. Bao, X. Wang, Q. Peng, and Y. D. Li, “Fluorescence resonant energy transfer biosensor based on upconversion-luminescent nanoparticles,” Angew. Chem. Int. Ed. Engl. 44(37), 6054–6057 (2005).
[CrossRef] [PubMed]

Boyer, J. C.

J. C. Boyer, L. A. Cuccia, and J. A. Capobianco, “Synthesis of colloidal upconverting NaYF4: Er3+/Yb3+ and Tm3+/Yb3+ monodisperse nanocrystals,” Nano Lett. 7(3), 847–852 (2007).
[CrossRef] [PubMed]

Brik, M. G.

D. Kasprowicz, M. G. Brik, A. Majchrowski, E. Michalski, and P. Gluchowski, “Up-conversion emission in triply-doped Ho3+/Yb3+/Tm3+ KGd(WO4)2 single crystals,” Opt. Commun. 284(12), 2895–2899 (2011).
[CrossRef]

Cao, C. Y.

L. L. Wang, C. Y. Cao, X. J. Xue, D. Zhao, D. S. Zhang, K. Z. Zheng, N. Liu, F. Shi, C. F. He, and W. P. Qin, “Effect of crystal structure and ions concentration on luminescence in Yb3+ and Tm3+ codoped fluoride microcrystals,” J. Fluor. Chem. 130(11), 1059–1062 (2009).
[CrossRef]

Cao, T.

C. Sun, F. Yang, T. Cao, Z. You, Y. Wang, J. Li, Z. Zhu, and C. Tu, “Infrared spectroscopic properties of Tm3+, Ho3+:NaY(WO4)2 single crystals,” J. Alloy. Comp. 509(25), 6987–6993 (2011).
[CrossRef]

Capobianco, J. A.

V. Mahalingam, R. Naccache, F. Vetrone, and J. A. Capobianco, “Enhancing upconverted white light in Tm3+/Yb3+/Ho3+-doped GdVO4 nanocrystals via incorporation of Li+ ions,” Opt. Express 20(1), 111–119 (2012).
[CrossRef] [PubMed]

V. Mahalingam, F. Vetrone, R. Naccache, A. Speghini, and J. A. Capobianco, “Colloidal Tm3+/Yb3+-Doped LiYF4 Nanocrystals: Multiple Luminescence spanning the UV to NIR Regions via low-energy excitation,” Adv. Mater. (Deerfield Beach Fla.) 21(40), 4025–4028 (2009).
[CrossRef]

J. C. Boyer, L. A. Cuccia, and J. A. Capobianco, “Synthesis of colloidal upconverting NaYF4: Er3+/Yb3+ and Tm3+/Yb3+ monodisperse nanocrystals,” Nano Lett. 7(3), 847–852 (2007).
[CrossRef] [PubMed]

Chang, J. A.

S. Jeong, N. Won, J. Lee, J. Bang, J. Yoo, S. G. Kim, J. A. Chang, J. Kim, and S. Kim, “Multiplexed near-infrared in vivo imaging complementarily using quantum dots and upconverting NaYF4:Yb3+,Tm3+ nanoparticles,” Chem. Commun. (Camb.) 47(28), 8022–8024 (2011).
[CrossRef] [PubMed]

Chatterjee, D. K.

D. K. Chatterjee, A. J. Rufaihah, and Y. Zhang, “Upconversion fluorescence imaging of cells and small animals using lanthanide doped nanocrystals,” Biomaterials 29(7), 937–943 (2008).
[CrossRef] [PubMed]

Chen, D.

D. Chen, Y. Yu, F. Huang, P. Huang, A. Yang, and Y. Wang, “Modifying the Size and Shape of Monodisperse Bifunctional Alkaline-Earth Fluoride Nanocrystals through Lanthanide Doping,” J. Am. Chem. Soc. 132(29), 9976–9978 (2010).
[CrossRef] [PubMed]

C. Liu, H. Wang, X. Li, and D. Chen, “Monodisperse, size-tunable and highly efficient beta-NaYF4:Yb,Er(Tm) up-conversion luminescent nanospheres: controllable synthesis and their surface modifications,” J. Mater. Chem. 19(21), 3546–3553 (2009).
[CrossRef]

P. Huang, F. Liu, D. Chen, Y. Wang, and Y. Yu, “Highly efficient near-infrared to visible upconversion luminescence in transparent glass ceramics containing Yb3+/Er3+:NaYF4 nanocrystals,” Phys. Status Solidi A 205(7), 1680–1684 (2008).
[CrossRef]

F. Liu, E. Ma, D. Chen, Y. Yu, and Y. Wang, “Tunable Red-Green Upconversion Luminescence in Novel Transparent Glass Ceramics Containing Er: NaYF4 Nanocrystals,” J. Phys. Chem. B 110(42), 20843–20846 (2006).
[CrossRef] [PubMed]

Chen, G.

G. Chen, T. Y. Ohulchanskyy, W. C. Law, H. Ågren, and P. N. Prasad, “Monodisperse NaYbF4:Tm3+/NaGdF4 core/shell nanocrystals with near-infrared to near-infrared upconversion photoluminescence and magnetic resonance properties,” Nanoscale 3(5), 2003–2008 (2011).
[CrossRef] [PubMed]

G. Chen, T. Y. Ohulchanskyy, R. Kumar, H. Ågren, and P. N. Prasad, “Ultrasmall monodisperse NaYF4:Yb3+/Tm3+ nanocrystals with enhanced near-infrared to near-infrared upconversion photoluminescence,” ACS Nano 4(6), 3163–3168 (2010).
[CrossRef] [PubMed]

Chen, G. Y.

Chen, H.

L. L. Wang, H. Chen, D. S. Zhang, D. Zhao, and W. P. Qin, “Dual-mode luminescence from lanthanide tri-doped NaYF4 nanocrystals,” Mater. Lett. 65(3), 504–506 (2011).
[CrossRef]

Cuccia, L. A.

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[CrossRef] [PubMed]

Deng, D.

C. Li, S. Xu, R. Ye, D. Deng, Y. Hua, S. Zhao, and S. Zhuang, “White up-conversion emission in Ho3+/Tm3+/Yb3+ tri-doped glass ceramics embedding BaF2 nanocrystals,” Physica B 406(9), 1698–1701 (2011).
[CrossRef]

Dong, W.

J. C. Zhou, Z. L. Yang, W. Dong, R. J. Tang, L. D. Sun, and C. H. Yan, “Bioimaging and toxicity assessments of near-infrared upconversion luminescent NaYF4:Yb,Tm nanocrystals,” Biomaterials 32(34), 9059–9067 (2011).
[CrossRef] [PubMed]

Gamelin, D. R.

M. Pollnau, D. R. Gamelin, S. R. Luthi, H. U. Gudel, and M. P. Hehlen, “Power dependence of upconversion luminescence in lanthanide and transition-metal-ion systems,” Phys. Rev. B 61(5), 3337–3346 (2000).
[CrossRef]

Gluchowski, P.

D. Kasprowicz, M. G. Brik, A. Majchrowski, E. Michalski, and P. Gluchowski, “Up-conversion emission in triply-doped Ho3+/Yb3+/Tm3+ KGd(WO4)2 single crystals,” Opt. Commun. 284(12), 2895–2899 (2011).
[CrossRef]

Gudel, H. U.

M. Pollnau, D. R. Gamelin, S. R. Luthi, H. U. Gudel, and M. P. Hehlen, “Power dependence of upconversion luminescence in lanthanide and transition-metal-ion systems,” Phys. Rev. B 61(5), 3337–3346 (2000).
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Guggenheim, H. J.

L. F. Johnson and H. J. Guggenheim, “Infrared-pumped visible laser,” Appl. Phys. Lett. 19(2), 44–47 (1971).
[CrossRef]

He, C. F.

L. L. Wang, C. Y. Cao, X. J. Xue, D. Zhao, D. S. Zhang, K. Z. Zheng, N. Liu, F. Shi, C. F. He, and W. P. Qin, “Effect of crystal structure and ions concentration on luminescence in Yb3+ and Tm3+ codoped fluoride microcrystals,” J. Fluor. Chem. 130(11), 1059–1062 (2009).
[CrossRef]

Hehlen, M. P.

M. Pollnau, D. R. Gamelin, S. R. Luthi, H. U. Gudel, and M. P. Hehlen, “Power dependence of upconversion luminescence in lanthanide and transition-metal-ion systems,” Phys. Rev. B 61(5), 3337–3346 (2000).
[CrossRef]

Hua, Y.

C. Li, S. Xu, R. Ye, D. Deng, Y. Hua, S. Zhao, and S. Zhuang, “White up-conversion emission in Ho3+/Tm3+/Yb3+ tri-doped glass ceramics embedding BaF2 nanocrystals,” Physica B 406(9), 1698–1701 (2011).
[CrossRef]

Huang, F.

D. Chen, Y. Yu, F. Huang, P. Huang, A. Yang, and Y. Wang, “Modifying the Size and Shape of Monodisperse Bifunctional Alkaline-Earth Fluoride Nanocrystals through Lanthanide Doping,” J. Am. Chem. Soc. 132(29), 9976–9978 (2010).
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Huang, P.

D. Chen, Y. Yu, F. Huang, P. Huang, A. Yang, and Y. Wang, “Modifying the Size and Shape of Monodisperse Bifunctional Alkaline-Earth Fluoride Nanocrystals through Lanthanide Doping,” J. Am. Chem. Soc. 132(29), 9976–9978 (2010).
[CrossRef] [PubMed]

P. Huang, F. Liu, D. Chen, Y. Wang, and Y. Yu, “Highly efficient near-infrared to visible upconversion luminescence in transparent glass ceramics containing Yb3+/Er3+:NaYF4 nanocrystals,” Phys. Status Solidi A 205(7), 1680–1684 (2008).
[CrossRef]

Huo, Z.

L. Y. Wang, R. X. Yan, Z. Huo, L. Wang, J. H. Zeng, H. Bao, X. Wang, Q. Peng, and Y. D. Li, “Fluorescence resonant energy transfer biosensor based on upconversion-luminescent nanoparticles,” Angew. Chem. Int. Ed. Engl. 44(37), 6054–6057 (2005).
[CrossRef] [PubMed]

Jeong, S.

S. Jeong, N. Won, J. Lee, J. Bang, J. Yoo, S. G. Kim, J. A. Chang, J. Kim, and S. Kim, “Multiplexed near-infrared in vivo imaging complementarily using quantum dots and upconverting NaYF4:Yb3+,Tm3+ nanoparticles,” Chem. Commun. (Camb.) 47(28), 8022–8024 (2011).
[CrossRef] [PubMed]

Johnson, L. F.

L. F. Johnson and H. J. Guggenheim, “Infrared-pumped visible laser,” Appl. Phys. Lett. 19(2), 44–47 (1971).
[CrossRef]

Kasprowicz, D.

D. Kasprowicz, M. G. Brik, A. Majchrowski, E. Michalski, and P. Gluchowski, “Up-conversion emission in triply-doped Ho3+/Yb3+/Tm3+ KGd(WO4)2 single crystals,” Opt. Commun. 284(12), 2895–2899 (2011).
[CrossRef]

Khanarian, N.

S. F. Lim, R. Riehn, W. S. Ryu, N. Khanarian, C. Tung, D. Tank, and R. H. Austin, “In vivo and scanning electron microscopy imaging of upconverting Nanophosphors in Caenorhabditis elegans,” Nano Lett. 6(2), 169–174 (2006).
[CrossRef]

Kim, J.

S. Jeong, N. Won, J. Lee, J. Bang, J. Yoo, S. G. Kim, J. A. Chang, J. Kim, and S. Kim, “Multiplexed near-infrared in vivo imaging complementarily using quantum dots and upconverting NaYF4:Yb3+,Tm3+ nanoparticles,” Chem. Commun. (Camb.) 47(28), 8022–8024 (2011).
[CrossRef] [PubMed]

Kim, R. J.

G. F. Wang, W. P. Qin, J. S. Zhang, L. L. Wang, G. D. Wei, P. F. Zhu, and R. J. Kim, “Controlled synthesis and luminescence properties from cubic to hexagonal NaYF4:Ln3+ (Ln = Eu and Yb/Tm) microcrystals,” J. Alloy. Comp. 475(1-2), 452–455 (2009).
[CrossRef]

G. F. Wang, W. P. Qin, L. L. Wang, G. D. Wei, P. F. Zhu, and R. J. Kim, “Intense ultraviolet upconversion luminescence from hexagonal NaYF4:Yb3+/Tm3+ microcrystals,” Opt. Express 16(16), 11907–11914 (2008).
[CrossRef] [PubMed]

Kim, S.

S. Jeong, N. Won, J. Lee, J. Bang, J. Yoo, S. G. Kim, J. A. Chang, J. Kim, and S. Kim, “Multiplexed near-infrared in vivo imaging complementarily using quantum dots and upconverting NaYF4:Yb3+,Tm3+ nanoparticles,” Chem. Commun. (Camb.) 47(28), 8022–8024 (2011).
[CrossRef] [PubMed]

Kim, S. G.

S. Jeong, N. Won, J. Lee, J. Bang, J. Yoo, S. G. Kim, J. A. Chang, J. Kim, and S. Kim, “Multiplexed near-infrared in vivo imaging complementarily using quantum dots and upconverting NaYF4:Yb3+,Tm3+ nanoparticles,” Chem. Commun. (Camb.) 47(28), 8022–8024 (2011).
[CrossRef] [PubMed]

Kumar, R.

G. Chen, T. Y. Ohulchanskyy, R. Kumar, H. Ågren, and P. N. Prasad, “Ultrasmall monodisperse NaYF4:Yb3+/Tm3+ nanocrystals with enhanced near-infrared to near-infrared upconversion photoluminescence,” ACS Nano 4(6), 3163–3168 (2010).
[CrossRef] [PubMed]

Law, W. C.

G. Chen, T. Y. Ohulchanskyy, W. C. Law, H. Ågren, and P. N. Prasad, “Monodisperse NaYbF4:Tm3+/NaGdF4 core/shell nanocrystals with near-infrared to near-infrared upconversion photoluminescence and magnetic resonance properties,” Nanoscale 3(5), 2003–2008 (2011).
[CrossRef] [PubMed]

Lee, J.

S. Jeong, N. Won, J. Lee, J. Bang, J. Yoo, S. G. Kim, J. A. Chang, J. Kim, and S. Kim, “Multiplexed near-infrared in vivo imaging complementarily using quantum dots and upconverting NaYF4:Yb3+,Tm3+ nanoparticles,” Chem. Commun. (Camb.) 47(28), 8022–8024 (2011).
[CrossRef] [PubMed]

Li, C.

C. Li, S. Xu, R. Ye, D. Deng, Y. Hua, S. Zhao, and S. Zhuang, “White up-conversion emission in Ho3+/Tm3+/Yb3+ tri-doped glass ceramics embedding BaF2 nanocrystals,” Physica B 406(9), 1698–1701 (2011).
[CrossRef]

Li, F.

J. Zhou, M. Yu, Y. Sun, X. Zhang, X. Zhu, Z. Wu, D. Wu, and F. Li, “Fluorine-18-labeled Gd3+/Yb3+/Er3+ co-doped NaYF4 nanophosphors for multimodality PET/MR/UCL imaging,” Biomaterials 32(4), 1148–1156 (2011).
[CrossRef] [PubMed]

L. Xiong, T. Yang, Y. Yang, C. Xu, and F. Li, “Long-term in vivo biodistribution imaging and toxicity of polyacrylic acid-coated upconversion nanophosphors,” Biomaterials 31(27), 7078–7085 (2010).
[CrossRef] [PubMed]

Li, J.

C. Sun, F. Yang, T. Cao, Z. You, Y. Wang, J. Li, Z. Zhu, and C. Tu, “Infrared spectroscopic properties of Tm3+, Ho3+:NaY(WO4)2 single crystals,” J. Alloy. Comp. 509(25), 6987–6993 (2011).
[CrossRef]

Li, L.

Li, P.

P. Li, Q. Peng, and Y. D. Li, “Dual-mode luminescent colloidal spheres from monodisperse rare-earth fluoride nanocrystals,” Adv. Mater. (Deerfield Beach Fla.) 21(19), 1945–1948 (2009).
[CrossRef]

Li, X.

C. Liu, H. Wang, X. Li, and D. Chen, “Monodisperse, size-tunable and highly efficient beta-NaYF4:Yb,Er(Tm) up-conversion luminescent nanospheres: controllable synthesis and their surface modifications,” J. Mater. Chem. 19(21), 3546–3553 (2009).
[CrossRef]

Li, Y. D.

P. Li, Q. Peng, and Y. D. Li, “Dual-mode luminescent colloidal spheres from monodisperse rare-earth fluoride nanocrystals,” Adv. Mater. (Deerfield Beach Fla.) 21(19), 1945–1948 (2009).
[CrossRef]

L. Y. Wang and Y. D. Li, “Green upconversion nanocrystals for DNA detection,” Chem. Commun. (Camb.) 24(24), 2557–2559 (2006).
[CrossRef] [PubMed]

L. Y. Wang, R. X. Yan, Z. Huo, L. Wang, J. H. Zeng, H. Bao, X. Wang, Q. Peng, and Y. D. Li, “Fluorescence resonant energy transfer biosensor based on upconversion-luminescent nanoparticles,” Angew. Chem. Int. Ed. Engl. 44(37), 6054–6057 (2005).
[CrossRef] [PubMed]

R. X. Yan and Y. D. Li, “Down/Up conversion in Ln3+-doped YF3 nanocrystals,” Adv. Funct. Mater. 15(5), 763–770 (2005).
[CrossRef]

J. H. Zeng, J. Su, Z. H. Li, R. X. Yan, and Y. D. Li, “Synthesis and Upconversion Luminescence of Hexagonal-Phase NaYF4:Yb, Er3+ Phosphors of controlled size and morphology,” Adv. Mater. (Deerfield Beach Fla.) 17(17), 2119–2123 (2005).
[CrossRef]

Li, Z. H.

J. H. Zeng, J. Su, Z. H. Li, R. X. Yan, and Y. D. Li, “Synthesis and Upconversion Luminescence of Hexagonal-Phase NaYF4:Yb, Er3+ Phosphors of controlled size and morphology,” Adv. Mater. (Deerfield Beach Fla.) 17(17), 2119–2123 (2005).
[CrossRef]

Liang, H. J.

Lim, S. F.

S. F. Lim, R. Riehn, W. S. Ryu, N. Khanarian, C. Tung, D. Tank, and R. H. Austin, “In vivo and scanning electron microscopy imaging of upconverting Nanophosphors in Caenorhabditis elegans,” Nano Lett. 6(2), 169–174 (2006).
[CrossRef]

Liu, C.

C. Liu, H. Wang, X. Li, and D. Chen, “Monodisperse, size-tunable and highly efficient beta-NaYF4:Yb,Er(Tm) up-conversion luminescent nanospheres: controllable synthesis and their surface modifications,” J. Mater. Chem. 19(21), 3546–3553 (2009).
[CrossRef]

Liu, C. H.

M. Wang, C. C. Mi, W. X. Wang, C. H. Liu, Y. F. Wu, Z.-R. Xu, C. B. Mao, and S. K. Xu, “Immunolabeling and NIR-excited fluorescent imaging of HeLa cells by using NaYF4:Yb,Er upconversion nanoparticles,” ACS Nano 3(6), 1580–1586 (2009).
[CrossRef] [PubMed]

Liu, F.

P. Huang, F. Liu, D. Chen, Y. Wang, and Y. Yu, “Highly efficient near-infrared to visible upconversion luminescence in transparent glass ceramics containing Yb3+/Er3+:NaYF4 nanocrystals,” Phys. Status Solidi A 205(7), 1680–1684 (2008).
[CrossRef]

F. Liu, E. Ma, D. Chen, Y. Yu, and Y. Wang, “Tunable Red-Green Upconversion Luminescence in Novel Transparent Glass Ceramics Containing Er: NaYF4 Nanocrystals,” J. Phys. Chem. B 110(42), 20843–20846 (2006).
[CrossRef] [PubMed]

Liu, N.

K. Z. Zheng, D. S. Zhang, D. Zhao, N. Liu, F. Shi, and W. P. Qin, “Bright white upconversion emission from Yb3+, Er3+, and Tm3+-codoped Gd2O3 nanotubes,” Phys. Chem. Chem. Phys. 12(27), 7620–7625 (2010).
[CrossRef] [PubMed]

L. L. Wang, C. Y. Cao, X. J. Xue, D. Zhao, D. S. Zhang, K. Z. Zheng, N. Liu, F. Shi, C. F. He, and W. P. Qin, “Effect of crystal structure and ions concentration on luminescence in Yb3+ and Tm3+ codoped fluoride microcrystals,” J. Fluor. Chem. 130(11), 1059–1062 (2009).
[CrossRef]

Liu, Y.

Luthi, S. R.

M. Pollnau, D. R. Gamelin, S. R. Luthi, H. U. Gudel, and M. P. Hehlen, “Power dependence of upconversion luminescence in lanthanide and transition-metal-ion systems,” Phys. Rev. B 61(5), 3337–3346 (2000).
[CrossRef]

Ma, E.

F. Liu, E. Ma, D. Chen, Y. Yu, and Y. Wang, “Tunable Red-Green Upconversion Luminescence in Novel Transparent Glass Ceramics Containing Er: NaYF4 Nanocrystals,” J. Phys. Chem. B 110(42), 20843–20846 (2006).
[CrossRef] [PubMed]

Mahalingam, V.

V. Mahalingam, R. Naccache, F. Vetrone, and J. A. Capobianco, “Enhancing upconverted white light in Tm3+/Yb3+/Ho3+-doped GdVO4 nanocrystals via incorporation of Li+ ions,” Opt. Express 20(1), 111–119 (2012).
[CrossRef] [PubMed]

V. Mahalingam, F. Vetrone, R. Naccache, A. Speghini, and J. A. Capobianco, “Colloidal Tm3+/Yb3+-Doped LiYF4 Nanocrystals: Multiple Luminescence spanning the UV to NIR Regions via low-energy excitation,” Adv. Mater. (Deerfield Beach Fla.) 21(40), 4025–4028 (2009).
[CrossRef]

Majchrowski, A.

D. Kasprowicz, M. G. Brik, A. Majchrowski, E. Michalski, and P. Gluchowski, “Up-conversion emission in triply-doped Ho3+/Yb3+/Tm3+ KGd(WO4)2 single crystals,” Opt. Commun. 284(12), 2895–2899 (2011).
[CrossRef]

Mao, C. B.

M. Wang, C. C. Mi, W. X. Wang, C. H. Liu, Y. F. Wu, Z.-R. Xu, C. B. Mao, and S. K. Xu, “Immunolabeling and NIR-excited fluorescent imaging of HeLa cells by using NaYF4:Yb,Er upconversion nanoparticles,” ACS Nano 3(6), 1580–1586 (2009).
[CrossRef] [PubMed]

Mi, C. C.

M. Wang, C. C. Mi, W. X. Wang, C. H. Liu, Y. F. Wu, Z.-R. Xu, C. B. Mao, and S. K. Xu, “Immunolabeling and NIR-excited fluorescent imaging of HeLa cells by using NaYF4:Yb,Er upconversion nanoparticles,” ACS Nano 3(6), 1580–1586 (2009).
[CrossRef] [PubMed]

Michalski, E.

D. Kasprowicz, M. G. Brik, A. Majchrowski, E. Michalski, and P. Gluchowski, “Up-conversion emission in triply-doped Ho3+/Yb3+/Tm3+ KGd(WO4)2 single crystals,” Opt. Commun. 284(12), 2895–2899 (2011).
[CrossRef]

Naccache, R.

V. Mahalingam, R. Naccache, F. Vetrone, and J. A. Capobianco, “Enhancing upconverted white light in Tm3+/Yb3+/Ho3+-doped GdVO4 nanocrystals via incorporation of Li+ ions,” Opt. Express 20(1), 111–119 (2012).
[CrossRef] [PubMed]

V. Mahalingam, F. Vetrone, R. Naccache, A. Speghini, and J. A. Capobianco, “Colloidal Tm3+/Yb3+-Doped LiYF4 Nanocrystals: Multiple Luminescence spanning the UV to NIR Regions via low-energy excitation,” Adv. Mater. (Deerfield Beach Fla.) 21(40), 4025–4028 (2009).
[CrossRef]

Ohulchanskyy, T. Y.

G. Chen, T. Y. Ohulchanskyy, W. C. Law, H. Ågren, and P. N. Prasad, “Monodisperse NaYbF4:Tm3+/NaGdF4 core/shell nanocrystals with near-infrared to near-infrared upconversion photoluminescence and magnetic resonance properties,” Nanoscale 3(5), 2003–2008 (2011).
[CrossRef] [PubMed]

G. Chen, T. Y. Ohulchanskyy, R. Kumar, H. Ågren, and P. N. Prasad, “Ultrasmall monodisperse NaYF4:Yb3+/Tm3+ nanocrystals with enhanced near-infrared to near-infrared upconversion photoluminescence,” ACS Nano 4(6), 3163–3168 (2010).
[CrossRef] [PubMed]

Peng, Q.

P. Li, Q. Peng, and Y. D. Li, “Dual-mode luminescent colloidal spheres from monodisperse rare-earth fluoride nanocrystals,” Adv. Mater. (Deerfield Beach Fla.) 21(19), 1945–1948 (2009).
[CrossRef]

L. Y. Wang, R. X. Yan, Z. Huo, L. Wang, J. H. Zeng, H. Bao, X. Wang, Q. Peng, and Y. D. Li, “Fluorescence resonant energy transfer biosensor based on upconversion-luminescent nanoparticles,” Angew. Chem. Int. Ed. Engl. 44(37), 6054–6057 (2005).
[CrossRef] [PubMed]

Pollnau, M.

M. Pollnau, D. R. Gamelin, S. R. Luthi, H. U. Gudel, and M. P. Hehlen, “Power dependence of upconversion luminescence in lanthanide and transition-metal-ion systems,” Phys. Rev. B 61(5), 3337–3346 (2000).
[CrossRef]

Prasad, P. N.

G. Chen, T. Y. Ohulchanskyy, W. C. Law, H. Ågren, and P. N. Prasad, “Monodisperse NaYbF4:Tm3+/NaGdF4 core/shell nanocrystals with near-infrared to near-infrared upconversion photoluminescence and magnetic resonance properties,” Nanoscale 3(5), 2003–2008 (2011).
[CrossRef] [PubMed]

G. Chen, T. Y. Ohulchanskyy, R. Kumar, H. Ågren, and P. N. Prasad, “Ultrasmall monodisperse NaYF4:Yb3+/Tm3+ nanocrystals with enhanced near-infrared to near-infrared upconversion photoluminescence,” ACS Nano 4(6), 3163–3168 (2010).
[CrossRef] [PubMed]

Qin, W. P.

L. L. Wang, H. Chen, D. S. Zhang, D. Zhao, and W. P. Qin, “Dual-mode luminescence from lanthanide tri-doped NaYF4 nanocrystals,” Mater. Lett. 65(3), 504–506 (2011).
[CrossRef]

K. Z. Zheng, D. S. Zhang, D. Zhao, N. Liu, F. Shi, and W. P. Qin, “Bright white upconversion emission from Yb3+, Er3+, and Tm3+-codoped Gd2O3 nanotubes,” Phys. Chem. Chem. Phys. 12(27), 7620–7625 (2010).
[CrossRef] [PubMed]

L. L. Wang, C. Y. Cao, X. J. Xue, D. Zhao, D. S. Zhang, K. Z. Zheng, N. Liu, F. Shi, C. F. He, and W. P. Qin, “Effect of crystal structure and ions concentration on luminescence in Yb3+ and Tm3+ codoped fluoride microcrystals,” J. Fluor. Chem. 130(11), 1059–1062 (2009).
[CrossRef]

G. F. Wang, W. P. Qin, J. S. Zhang, L. L. Wang, G. D. Wei, P. F. Zhu, and R. J. Kim, “Controlled synthesis and luminescence properties from cubic to hexagonal NaYF4:Ln3+ (Ln = Eu and Yb/Tm) microcrystals,” J. Alloy. Comp. 475(1-2), 452–455 (2009).
[CrossRef]

G. F. Wang, W. P. Qin, L. L. Wang, G. D. Wei, P. F. Zhu, and R. J. Kim, “Intense ultraviolet upconversion luminescence from hexagonal NaYF4:Yb3+/Tm3+ microcrystals,” Opt. Express 16(16), 11907–11914 (2008).
[CrossRef] [PubMed]

Riehn, R.

S. F. Lim, R. Riehn, W. S. Ryu, N. Khanarian, C. Tung, D. Tank, and R. H. Austin, “In vivo and scanning electron microscopy imaging of upconverting Nanophosphors in Caenorhabditis elegans,” Nano Lett. 6(2), 169–174 (2006).
[CrossRef]

Rufaihah, A. J.

D. K. Chatterjee, A. J. Rufaihah, and Y. Zhang, “Upconversion fluorescence imaging of cells and small animals using lanthanide doped nanocrystals,” Biomaterials 29(7), 937–943 (2008).
[CrossRef] [PubMed]

Ryu, W. S.

S. F. Lim, R. Riehn, W. S. Ryu, N. Khanarian, C. Tung, D. Tank, and R. H. Austin, “In vivo and scanning electron microscopy imaging of upconverting Nanophosphors in Caenorhabditis elegans,” Nano Lett. 6(2), 169–174 (2006).
[CrossRef]

Shi, F.

K. Z. Zheng, D. S. Zhang, D. Zhao, N. Liu, F. Shi, and W. P. Qin, “Bright white upconversion emission from Yb3+, Er3+, and Tm3+-codoped Gd2O3 nanotubes,” Phys. Chem. Chem. Phys. 12(27), 7620–7625 (2010).
[CrossRef] [PubMed]

L. L. Wang, C. Y. Cao, X. J. Xue, D. Zhao, D. S. Zhang, K. Z. Zheng, N. Liu, F. Shi, C. F. He, and W. P. Qin, “Effect of crystal structure and ions concentration on luminescence in Yb3+ and Tm3+ codoped fluoride microcrystals,” J. Fluor. Chem. 130(11), 1059–1062 (2009).
[CrossRef]

Speghini, A.

V. Mahalingam, F. Vetrone, R. Naccache, A. Speghini, and J. A. Capobianco, “Colloidal Tm3+/Yb3+-Doped LiYF4 Nanocrystals: Multiple Luminescence spanning the UV to NIR Regions via low-energy excitation,” Adv. Mater. (Deerfield Beach Fla.) 21(40), 4025–4028 (2009).
[CrossRef]

Su, J.

J. H. Zeng, J. Su, Z. H. Li, R. X. Yan, and Y. D. Li, “Synthesis and Upconversion Luminescence of Hexagonal-Phase NaYF4:Yb, Er3+ Phosphors of controlled size and morphology,” Adv. Mater. (Deerfield Beach Fla.) 17(17), 2119–2123 (2005).
[CrossRef]

Sun, C.

C. Sun, F. Yang, T. Cao, Z. You, Y. Wang, J. Li, Z. Zhu, and C. Tu, “Infrared spectroscopic properties of Tm3+, Ho3+:NaY(WO4)2 single crystals,” J. Alloy. Comp. 509(25), 6987–6993 (2011).
[CrossRef]

Sun, L. D.

J. C. Zhou, Z. L. Yang, W. Dong, R. J. Tang, L. D. Sun, and C. H. Yan, “Bioimaging and toxicity assessments of near-infrared upconversion luminescent NaYF4:Yb,Tm nanocrystals,” Biomaterials 32(34), 9059–9067 (2011).
[CrossRef] [PubMed]

Sun, Y.

J. Zhou, M. Yu, Y. Sun, X. Zhang, X. Zhu, Z. Wu, D. Wu, and F. Li, “Fluorine-18-labeled Gd3+/Yb3+/Er3+ co-doped NaYF4 nanophosphors for multimodality PET/MR/UCL imaging,” Biomaterials 32(4), 1148–1156 (2011).
[CrossRef] [PubMed]

Tang, R. J.

J. C. Zhou, Z. L. Yang, W. Dong, R. J. Tang, L. D. Sun, and C. H. Yan, “Bioimaging and toxicity assessments of near-infrared upconversion luminescent NaYF4:Yb,Tm nanocrystals,” Biomaterials 32(34), 9059–9067 (2011).
[CrossRef] [PubMed]

Tank, D.

S. F. Lim, R. Riehn, W. S. Ryu, N. Khanarian, C. Tung, D. Tank, and R. H. Austin, “In vivo and scanning electron microscopy imaging of upconverting Nanophosphors in Caenorhabditis elegans,” Nano Lett. 6(2), 169–174 (2006).
[CrossRef]

Tu, C.

C. Sun, F. Yang, T. Cao, Z. You, Y. Wang, J. Li, Z. Zhu, and C. Tu, “Infrared spectroscopic properties of Tm3+, Ho3+:NaY(WO4)2 single crystals,” J. Alloy. Comp. 509(25), 6987–6993 (2011).
[CrossRef]

Tung, C.

S. F. Lim, R. Riehn, W. S. Ryu, N. Khanarian, C. Tung, D. Tank, and R. H. Austin, “In vivo and scanning electron microscopy imaging of upconverting Nanophosphors in Caenorhabditis elegans,” Nano Lett. 6(2), 169–174 (2006).
[CrossRef]

Vetrone, F.

V. Mahalingam, R. Naccache, F. Vetrone, and J. A. Capobianco, “Enhancing upconverted white light in Tm3+/Yb3+/Ho3+-doped GdVO4 nanocrystals via incorporation of Li+ ions,” Opt. Express 20(1), 111–119 (2012).
[CrossRef] [PubMed]

V. Mahalingam, F. Vetrone, R. Naccache, A. Speghini, and J. A. Capobianco, “Colloidal Tm3+/Yb3+-Doped LiYF4 Nanocrystals: Multiple Luminescence spanning the UV to NIR Regions via low-energy excitation,” Adv. Mater. (Deerfield Beach Fla.) 21(40), 4025–4028 (2009).
[CrossRef]

Wang, G. F.

G. F. Wang, W. P. Qin, J. S. Zhang, L. L. Wang, G. D. Wei, P. F. Zhu, and R. J. Kim, “Controlled synthesis and luminescence properties from cubic to hexagonal NaYF4:Ln3+ (Ln = Eu and Yb/Tm) microcrystals,” J. Alloy. Comp. 475(1-2), 452–455 (2009).
[CrossRef]

G. F. Wang, W. P. Qin, L. L. Wang, G. D. Wei, P. F. Zhu, and R. J. Kim, “Intense ultraviolet upconversion luminescence from hexagonal NaYF4:Yb3+/Tm3+ microcrystals,” Opt. Express 16(16), 11907–11914 (2008).
[CrossRef] [PubMed]

Wang, H.

C. Liu, H. Wang, X. Li, and D. Chen, “Monodisperse, size-tunable and highly efficient beta-NaYF4:Yb,Er(Tm) up-conversion luminescent nanospheres: controllable synthesis and their surface modifications,” J. Mater. Chem. 19(21), 3546–3553 (2009).
[CrossRef]

Wang, L.

L. Y. Wang, R. X. Yan, Z. Huo, L. Wang, J. H. Zeng, H. Bao, X. Wang, Q. Peng, and Y. D. Li, “Fluorescence resonant energy transfer biosensor based on upconversion-luminescent nanoparticles,” Angew. Chem. Int. Ed. Engl. 44(37), 6054–6057 (2005).
[CrossRef] [PubMed]

Wang, L. L.

L. L. Wang, H. Chen, D. S. Zhang, D. Zhao, and W. P. Qin, “Dual-mode luminescence from lanthanide tri-doped NaYF4 nanocrystals,” Mater. Lett. 65(3), 504–506 (2011).
[CrossRef]

G. F. Wang, W. P. Qin, J. S. Zhang, L. L. Wang, G. D. Wei, P. F. Zhu, and R. J. Kim, “Controlled synthesis and luminescence properties from cubic to hexagonal NaYF4:Ln3+ (Ln = Eu and Yb/Tm) microcrystals,” J. Alloy. Comp. 475(1-2), 452–455 (2009).
[CrossRef]

L. L. Wang, C. Y. Cao, X. J. Xue, D. Zhao, D. S. Zhang, K. Z. Zheng, N. Liu, F. Shi, C. F. He, and W. P. Qin, “Effect of crystal structure and ions concentration on luminescence in Yb3+ and Tm3+ codoped fluoride microcrystals,” J. Fluor. Chem. 130(11), 1059–1062 (2009).
[CrossRef]

G. F. Wang, W. P. Qin, L. L. Wang, G. D. Wei, P. F. Zhu, and R. J. Kim, “Intense ultraviolet upconversion luminescence from hexagonal NaYF4:Yb3+/Tm3+ microcrystals,” Opt. Express 16(16), 11907–11914 (2008).
[CrossRef] [PubMed]

Wang, L. Y.

L. Y. Wang and Y. D. Li, “Green upconversion nanocrystals for DNA detection,” Chem. Commun. (Camb.) 24(24), 2557–2559 (2006).
[CrossRef] [PubMed]

L. Y. Wang, R. X. Yan, Z. Huo, L. Wang, J. H. Zeng, H. Bao, X. Wang, Q. Peng, and Y. D. Li, “Fluorescence resonant energy transfer biosensor based on upconversion-luminescent nanoparticles,” Angew. Chem. Int. Ed. Engl. 44(37), 6054–6057 (2005).
[CrossRef] [PubMed]

Wang, M.

M. Wang, C. C. Mi, W. X. Wang, C. H. Liu, Y. F. Wu, Z.-R. Xu, C. B. Mao, and S. K. Xu, “Immunolabeling and NIR-excited fluorescent imaging of HeLa cells by using NaYF4:Yb,Er upconversion nanoparticles,” ACS Nano 3(6), 1580–1586 (2009).
[CrossRef] [PubMed]

Wang, W. X.

M. Wang, C. C. Mi, W. X. Wang, C. H. Liu, Y. F. Wu, Z.-R. Xu, C. B. Mao, and S. K. Xu, “Immunolabeling and NIR-excited fluorescent imaging of HeLa cells by using NaYF4:Yb,Er upconversion nanoparticles,” ACS Nano 3(6), 1580–1586 (2009).
[CrossRef] [PubMed]

Wang, X.

L. Y. Wang, R. X. Yan, Z. Huo, L. Wang, J. H. Zeng, H. Bao, X. Wang, Q. Peng, and Y. D. Li, “Fluorescence resonant energy transfer biosensor based on upconversion-luminescent nanoparticles,” Angew. Chem. Int. Ed. Engl. 44(37), 6054–6057 (2005).
[CrossRef] [PubMed]

Wang, Y.

C. Sun, F. Yang, T. Cao, Z. You, Y. Wang, J. Li, Z. Zhu, and C. Tu, “Infrared spectroscopic properties of Tm3+, Ho3+:NaY(WO4)2 single crystals,” J. Alloy. Comp. 509(25), 6987–6993 (2011).
[CrossRef]

D. Chen, Y. Yu, F. Huang, P. Huang, A. Yang, and Y. Wang, “Modifying the Size and Shape of Monodisperse Bifunctional Alkaline-Earth Fluoride Nanocrystals through Lanthanide Doping,” J. Am. Chem. Soc. 132(29), 9976–9978 (2010).
[CrossRef] [PubMed]

P. Huang, F. Liu, D. Chen, Y. Wang, and Y. Yu, “Highly efficient near-infrared to visible upconversion luminescence in transparent glass ceramics containing Yb3+/Er3+:NaYF4 nanocrystals,” Phys. Status Solidi A 205(7), 1680–1684 (2008).
[CrossRef]

F. Liu, E. Ma, D. Chen, Y. Yu, and Y. Wang, “Tunable Red-Green Upconversion Luminescence in Novel Transparent Glass Ceramics Containing Er: NaYF4 Nanocrystals,” J. Phys. Chem. B 110(42), 20843–20846 (2006).
[CrossRef] [PubMed]

Weber, M. J.

M. J. Weber, “Multiphonon relaxation of Rare-Earth Ions in Yttrium Orthoaluminate,” Phys. Rev. B 8(1), 54–64 (1973).
[CrossRef]

Wei, G. D.

G. F. Wang, W. P. Qin, J. S. Zhang, L. L. Wang, G. D. Wei, P. F. Zhu, and R. J. Kim, “Controlled synthesis and luminescence properties from cubic to hexagonal NaYF4:Ln3+ (Ln = Eu and Yb/Tm) microcrystals,” J. Alloy. Comp. 475(1-2), 452–455 (2009).
[CrossRef]

G. F. Wang, W. P. Qin, L. L. Wang, G. D. Wei, P. F. Zhu, and R. J. Kim, “Intense ultraviolet upconversion luminescence from hexagonal NaYF4:Yb3+/Tm3+ microcrystals,” Opt. Express 16(16), 11907–11914 (2008).
[CrossRef] [PubMed]

Won, N.

S. Jeong, N. Won, J. Lee, J. Bang, J. Yoo, S. G. Kim, J. A. Chang, J. Kim, and S. Kim, “Multiplexed near-infrared in vivo imaging complementarily using quantum dots and upconverting NaYF4:Yb3+,Tm3+ nanoparticles,” Chem. Commun. (Camb.) 47(28), 8022–8024 (2011).
[CrossRef] [PubMed]

Wu, D.

J. Zhou, M. Yu, Y. Sun, X. Zhang, X. Zhu, Z. Wu, D. Wu, and F. Li, “Fluorine-18-labeled Gd3+/Yb3+/Er3+ co-doped NaYF4 nanophosphors for multimodality PET/MR/UCL imaging,” Biomaterials 32(4), 1148–1156 (2011).
[CrossRef] [PubMed]

Wu, Y. F.

M. Wang, C. C. Mi, W. X. Wang, C. H. Liu, Y. F. Wu, Z.-R. Xu, C. B. Mao, and S. K. Xu, “Immunolabeling and NIR-excited fluorescent imaging of HeLa cells by using NaYF4:Yb,Er upconversion nanoparticles,” ACS Nano 3(6), 1580–1586 (2009).
[CrossRef] [PubMed]

Wu, Z.

J. Zhou, M. Yu, Y. Sun, X. Zhang, X. Zhu, Z. Wu, D. Wu, and F. Li, “Fluorine-18-labeled Gd3+/Yb3+/Er3+ co-doped NaYF4 nanophosphors for multimodality PET/MR/UCL imaging,” Biomaterials 32(4), 1148–1156 (2011).
[CrossRef] [PubMed]

Xiong, L.

L. Xiong, T. Yang, Y. Yang, C. Xu, and F. Li, “Long-term in vivo biodistribution imaging and toxicity of polyacrylic acid-coated upconversion nanophosphors,” Biomaterials 31(27), 7078–7085 (2010).
[CrossRef] [PubMed]

Xu, C.

L. Xiong, T. Yang, Y. Yang, C. Xu, and F. Li, “Long-term in vivo biodistribution imaging and toxicity of polyacrylic acid-coated upconversion nanophosphors,” Biomaterials 31(27), 7078–7085 (2010).
[CrossRef] [PubMed]

Xu, S.

C. Li, S. Xu, R. Ye, D. Deng, Y. Hua, S. Zhao, and S. Zhuang, “White up-conversion emission in Ho3+/Tm3+/Yb3+ tri-doped glass ceramics embedding BaF2 nanocrystals,” Physica B 406(9), 1698–1701 (2011).
[CrossRef]

Xu, S. K.

M. Wang, C. C. Mi, W. X. Wang, C. H. Liu, Y. F. Wu, Z.-R. Xu, C. B. Mao, and S. K. Xu, “Immunolabeling and NIR-excited fluorescent imaging of HeLa cells by using NaYF4:Yb,Er upconversion nanoparticles,” ACS Nano 3(6), 1580–1586 (2009).
[CrossRef] [PubMed]

Xu, Z.-R.

M. Wang, C. C. Mi, W. X. Wang, C. H. Liu, Y. F. Wu, Z.-R. Xu, C. B. Mao, and S. K. Xu, “Immunolabeling and NIR-excited fluorescent imaging of HeLa cells by using NaYF4:Yb,Er upconversion nanoparticles,” ACS Nano 3(6), 1580–1586 (2009).
[CrossRef] [PubMed]

Xue, X. J.

L. L. Wang, C. Y. Cao, X. J. Xue, D. Zhao, D. S. Zhang, K. Z. Zheng, N. Liu, F. Shi, C. F. He, and W. P. Qin, “Effect of crystal structure and ions concentration on luminescence in Yb3+ and Tm3+ codoped fluoride microcrystals,” J. Fluor. Chem. 130(11), 1059–1062 (2009).
[CrossRef]

Yan, C. H.

J. C. Zhou, Z. L. Yang, W. Dong, R. J. Tang, L. D. Sun, and C. H. Yan, “Bioimaging and toxicity assessments of near-infrared upconversion luminescent NaYF4:Yb,Tm nanocrystals,” Biomaterials 32(34), 9059–9067 (2011).
[CrossRef] [PubMed]

Yan, R. X.

J. H. Zeng, J. Su, Z. H. Li, R. X. Yan, and Y. D. Li, “Synthesis and Upconversion Luminescence of Hexagonal-Phase NaYF4:Yb, Er3+ Phosphors of controlled size and morphology,” Adv. Mater. (Deerfield Beach Fla.) 17(17), 2119–2123 (2005).
[CrossRef]

L. Y. Wang, R. X. Yan, Z. Huo, L. Wang, J. H. Zeng, H. Bao, X. Wang, Q. Peng, and Y. D. Li, “Fluorescence resonant energy transfer biosensor based on upconversion-luminescent nanoparticles,” Angew. Chem. Int. Ed. Engl. 44(37), 6054–6057 (2005).
[CrossRef] [PubMed]

R. X. Yan and Y. D. Li, “Down/Up conversion in Ln3+-doped YF3 nanocrystals,” Adv. Funct. Mater. 15(5), 763–770 (2005).
[CrossRef]

Yang, A.

D. Chen, Y. Yu, F. Huang, P. Huang, A. Yang, and Y. Wang, “Modifying the Size and Shape of Monodisperse Bifunctional Alkaline-Earth Fluoride Nanocrystals through Lanthanide Doping,” J. Am. Chem. Soc. 132(29), 9976–9978 (2010).
[CrossRef] [PubMed]

Yang, C. H.

Yang, F.

C. Sun, F. Yang, T. Cao, Z. You, Y. Wang, J. Li, Z. Zhu, and C. Tu, “Infrared spectroscopic properties of Tm3+, Ho3+:NaY(WO4)2 single crystals,” J. Alloy. Comp. 509(25), 6987–6993 (2011).
[CrossRef]

Yang, T.

L. Xiong, T. Yang, Y. Yang, C. Xu, and F. Li, “Long-term in vivo biodistribution imaging and toxicity of polyacrylic acid-coated upconversion nanophosphors,” Biomaterials 31(27), 7078–7085 (2010).
[CrossRef] [PubMed]

Yang, Y.

L. Xiong, T. Yang, Y. Yang, C. Xu, and F. Li, “Long-term in vivo biodistribution imaging and toxicity of polyacrylic acid-coated upconversion nanophosphors,” Biomaterials 31(27), 7078–7085 (2010).
[CrossRef] [PubMed]

Yang, Z. L.

J. C. Zhou, Z. L. Yang, W. Dong, R. J. Tang, L. D. Sun, and C. H. Yan, “Bioimaging and toxicity assessments of near-infrared upconversion luminescent NaYF4:Yb,Tm nanocrystals,” Biomaterials 32(34), 9059–9067 (2011).
[CrossRef] [PubMed]

Ye, R.

C. Li, S. Xu, R. Ye, D. Deng, Y. Hua, S. Zhao, and S. Zhuang, “White up-conversion emission in Ho3+/Tm3+/Yb3+ tri-doped glass ceramics embedding BaF2 nanocrystals,” Physica B 406(9), 1698–1701 (2011).
[CrossRef]

Yoo, J.

S. Jeong, N. Won, J. Lee, J. Bang, J. Yoo, S. G. Kim, J. A. Chang, J. Kim, and S. Kim, “Multiplexed near-infrared in vivo imaging complementarily using quantum dots and upconverting NaYF4:Yb3+,Tm3+ nanoparticles,” Chem. Commun. (Camb.) 47(28), 8022–8024 (2011).
[CrossRef] [PubMed]

You, Z.

C. Sun, F. Yang, T. Cao, Z. You, Y. Wang, J. Li, Z. Zhu, and C. Tu, “Infrared spectroscopic properties of Tm3+, Ho3+:NaY(WO4)2 single crystals,” J. Alloy. Comp. 509(25), 6987–6993 (2011).
[CrossRef]

Yu, M.

J. Zhou, M. Yu, Y. Sun, X. Zhang, X. Zhu, Z. Wu, D. Wu, and F. Li, “Fluorine-18-labeled Gd3+/Yb3+/Er3+ co-doped NaYF4 nanophosphors for multimodality PET/MR/UCL imaging,” Biomaterials 32(4), 1148–1156 (2011).
[CrossRef] [PubMed]

Yu, Y.

D. Chen, Y. Yu, F. Huang, P. Huang, A. Yang, and Y. Wang, “Modifying the Size and Shape of Monodisperse Bifunctional Alkaline-Earth Fluoride Nanocrystals through Lanthanide Doping,” J. Am. Chem. Soc. 132(29), 9976–9978 (2010).
[CrossRef] [PubMed]

P. Huang, F. Liu, D. Chen, Y. Wang, and Y. Yu, “Highly efficient near-infrared to visible upconversion luminescence in transparent glass ceramics containing Yb3+/Er3+:NaYF4 nanocrystals,” Phys. Status Solidi A 205(7), 1680–1684 (2008).
[CrossRef]

F. Liu, E. Ma, D. Chen, Y. Yu, and Y. Wang, “Tunable Red-Green Upconversion Luminescence in Novel Transparent Glass Ceramics Containing Er: NaYF4 Nanocrystals,” J. Phys. Chem. B 110(42), 20843–20846 (2006).
[CrossRef] [PubMed]

Zeng, J. H.

L. Y. Wang, R. X. Yan, Z. Huo, L. Wang, J. H. Zeng, H. Bao, X. Wang, Q. Peng, and Y. D. Li, “Fluorescence resonant energy transfer biosensor based on upconversion-luminescent nanoparticles,” Angew. Chem. Int. Ed. Engl. 44(37), 6054–6057 (2005).
[CrossRef] [PubMed]

J. H. Zeng, J. Su, Z. H. Li, R. X. Yan, and Y. D. Li, “Synthesis and Upconversion Luminescence of Hexagonal-Phase NaYF4:Yb, Er3+ Phosphors of controlled size and morphology,” Adv. Mater. (Deerfield Beach Fla.) 17(17), 2119–2123 (2005).
[CrossRef]

Zhang, D. S.

L. L. Wang, H. Chen, D. S. Zhang, D. Zhao, and W. P. Qin, “Dual-mode luminescence from lanthanide tri-doped NaYF4 nanocrystals,” Mater. Lett. 65(3), 504–506 (2011).
[CrossRef]

K. Z. Zheng, D. S. Zhang, D. Zhao, N. Liu, F. Shi, and W. P. Qin, “Bright white upconversion emission from Yb3+, Er3+, and Tm3+-codoped Gd2O3 nanotubes,” Phys. Chem. Chem. Phys. 12(27), 7620–7625 (2010).
[CrossRef] [PubMed]

L. L. Wang, C. Y. Cao, X. J. Xue, D. Zhao, D. S. Zhang, K. Z. Zheng, N. Liu, F. Shi, C. F. He, and W. P. Qin, “Effect of crystal structure and ions concentration on luminescence in Yb3+ and Tm3+ codoped fluoride microcrystals,” J. Fluor. Chem. 130(11), 1059–1062 (2009).
[CrossRef]

Zhang, J. S.

G. F. Wang, W. P. Qin, J. S. Zhang, L. L. Wang, G. D. Wei, P. F. Zhu, and R. J. Kim, “Controlled synthesis and luminescence properties from cubic to hexagonal NaYF4:Ln3+ (Ln = Eu and Yb/Tm) microcrystals,” J. Alloy. Comp. 475(1-2), 452–455 (2009).
[CrossRef]

Zhang, X.

J. Zhou, M. Yu, Y. Sun, X. Zhang, X. Zhu, Z. Wu, D. Wu, and F. Li, “Fluorine-18-labeled Gd3+/Yb3+/Er3+ co-doped NaYF4 nanophosphors for multimodality PET/MR/UCL imaging,” Biomaterials 32(4), 1148–1156 (2011).
[CrossRef] [PubMed]

Zhang, Y.

D. K. Chatterjee, A. J. Rufaihah, and Y. Zhang, “Upconversion fluorescence imaging of cells and small animals using lanthanide doped nanocrystals,” Biomaterials 29(7), 937–943 (2008).
[CrossRef] [PubMed]

Zhang, Z. G.

Zhao, D.

L. L. Wang, H. Chen, D. S. Zhang, D. Zhao, and W. P. Qin, “Dual-mode luminescence from lanthanide tri-doped NaYF4 nanocrystals,” Mater. Lett. 65(3), 504–506 (2011).
[CrossRef]

K. Z. Zheng, D. S. Zhang, D. Zhao, N. Liu, F. Shi, and W. P. Qin, “Bright white upconversion emission from Yb3+, Er3+, and Tm3+-codoped Gd2O3 nanotubes,” Phys. Chem. Chem. Phys. 12(27), 7620–7625 (2010).
[CrossRef] [PubMed]

L. L. Wang, C. Y. Cao, X. J. Xue, D. Zhao, D. S. Zhang, K. Z. Zheng, N. Liu, F. Shi, C. F. He, and W. P. Qin, “Effect of crystal structure and ions concentration on luminescence in Yb3+ and Tm3+ codoped fluoride microcrystals,” J. Fluor. Chem. 130(11), 1059–1062 (2009).
[CrossRef]

Zhao, S.

C. Li, S. Xu, R. Ye, D. Deng, Y. Hua, S. Zhao, and S. Zhuang, “White up-conversion emission in Ho3+/Tm3+/Yb3+ tri-doped glass ceramics embedding BaF2 nanocrystals,” Physica B 406(9), 1698–1701 (2011).
[CrossRef]

Zheng, K. Z.

K. Z. Zheng, D. S. Zhang, D. Zhao, N. Liu, F. Shi, and W. P. Qin, “Bright white upconversion emission from Yb3+, Er3+, and Tm3+-codoped Gd2O3 nanotubes,” Phys. Chem. Chem. Phys. 12(27), 7620–7625 (2010).
[CrossRef] [PubMed]

L. L. Wang, C. Y. Cao, X. J. Xue, D. Zhao, D. S. Zhang, K. Z. Zheng, N. Liu, F. Shi, C. F. He, and W. P. Qin, “Effect of crystal structure and ions concentration on luminescence in Yb3+ and Tm3+ codoped fluoride microcrystals,” J. Fluor. Chem. 130(11), 1059–1062 (2009).
[CrossRef]

Zhou, J.

J. Zhou, M. Yu, Y. Sun, X. Zhang, X. Zhu, Z. Wu, D. Wu, and F. Li, “Fluorine-18-labeled Gd3+/Yb3+/Er3+ co-doped NaYF4 nanophosphors for multimodality PET/MR/UCL imaging,” Biomaterials 32(4), 1148–1156 (2011).
[CrossRef] [PubMed]

Zhou, J. C.

J. C. Zhou, Z. L. Yang, W. Dong, R. J. Tang, L. D. Sun, and C. H. Yan, “Bioimaging and toxicity assessments of near-infrared upconversion luminescent NaYF4:Yb,Tm nanocrystals,” Biomaterials 32(34), 9059–9067 (2011).
[CrossRef] [PubMed]

Zhu, P. F.

G. F. Wang, W. P. Qin, J. S. Zhang, L. L. Wang, G. D. Wei, P. F. Zhu, and R. J. Kim, “Controlled synthesis and luminescence properties from cubic to hexagonal NaYF4:Ln3+ (Ln = Eu and Yb/Tm) microcrystals,” J. Alloy. Comp. 475(1-2), 452–455 (2009).
[CrossRef]

G. F. Wang, W. P. Qin, L. L. Wang, G. D. Wei, P. F. Zhu, and R. J. Kim, “Intense ultraviolet upconversion luminescence from hexagonal NaYF4:Yb3+/Tm3+ microcrystals,” Opt. Express 16(16), 11907–11914 (2008).
[CrossRef] [PubMed]

Zhu, X.

J. Zhou, M. Yu, Y. Sun, X. Zhang, X. Zhu, Z. Wu, D. Wu, and F. Li, “Fluorine-18-labeled Gd3+/Yb3+/Er3+ co-doped NaYF4 nanophosphors for multimodality PET/MR/UCL imaging,” Biomaterials 32(4), 1148–1156 (2011).
[CrossRef] [PubMed]

Zhu, Z.

C. Sun, F. Yang, T. Cao, Z. You, Y. Wang, J. Li, Z. Zhu, and C. Tu, “Infrared spectroscopic properties of Tm3+, Ho3+:NaY(WO4)2 single crystals,” J. Alloy. Comp. 509(25), 6987–6993 (2011).
[CrossRef]

Zhuang, S.

C. Li, S. Xu, R. Ye, D. Deng, Y. Hua, S. Zhao, and S. Zhuang, “White up-conversion emission in Ho3+/Tm3+/Yb3+ tri-doped glass ceramics embedding BaF2 nanocrystals,” Physica B 406(9), 1698–1701 (2011).
[CrossRef]

ACS Nano (2)

M. Wang, C. C. Mi, W. X. Wang, C. H. Liu, Y. F. Wu, Z.-R. Xu, C. B. Mao, and S. K. Xu, “Immunolabeling and NIR-excited fluorescent imaging of HeLa cells by using NaYF4:Yb,Er upconversion nanoparticles,” ACS Nano 3(6), 1580–1586 (2009).
[CrossRef] [PubMed]

G. Chen, T. Y. Ohulchanskyy, R. Kumar, H. Ågren, and P. N. Prasad, “Ultrasmall monodisperse NaYF4:Yb3+/Tm3+ nanocrystals with enhanced near-infrared to near-infrared upconversion photoluminescence,” ACS Nano 4(6), 3163–3168 (2010).
[CrossRef] [PubMed]

Adv. Funct. Mater. (1)

R. X. Yan and Y. D. Li, “Down/Up conversion in Ln3+-doped YF3 nanocrystals,” Adv. Funct. Mater. 15(5), 763–770 (2005).
[CrossRef]

Adv. Mater. (Deerfield Beach Fla.) (3)

V. Mahalingam, F. Vetrone, R. Naccache, A. Speghini, and J. A. Capobianco, “Colloidal Tm3+/Yb3+-Doped LiYF4 Nanocrystals: Multiple Luminescence spanning the UV to NIR Regions via low-energy excitation,” Adv. Mater. (Deerfield Beach Fla.) 21(40), 4025–4028 (2009).
[CrossRef]

J. H. Zeng, J. Su, Z. H. Li, R. X. Yan, and Y. D. Li, “Synthesis and Upconversion Luminescence of Hexagonal-Phase NaYF4:Yb, Er3+ Phosphors of controlled size and morphology,” Adv. Mater. (Deerfield Beach Fla.) 17(17), 2119–2123 (2005).
[CrossRef]

P. Li, Q. Peng, and Y. D. Li, “Dual-mode luminescent colloidal spheres from monodisperse rare-earth fluoride nanocrystals,” Adv. Mater. (Deerfield Beach Fla.) 21(19), 1945–1948 (2009).
[CrossRef]

Angew. Chem. Int. Ed. Engl. (1)

L. Y. Wang, R. X. Yan, Z. Huo, L. Wang, J. H. Zeng, H. Bao, X. Wang, Q. Peng, and Y. D. Li, “Fluorescence resonant energy transfer biosensor based on upconversion-luminescent nanoparticles,” Angew. Chem. Int. Ed. Engl. 44(37), 6054–6057 (2005).
[CrossRef] [PubMed]

Appl. Phys. Lett. (1)

L. F. Johnson and H. J. Guggenheim, “Infrared-pumped visible laser,” Appl. Phys. Lett. 19(2), 44–47 (1971).
[CrossRef]

Biomaterials (4)

L. Xiong, T. Yang, Y. Yang, C. Xu, and F. Li, “Long-term in vivo biodistribution imaging and toxicity of polyacrylic acid-coated upconversion nanophosphors,” Biomaterials 31(27), 7078–7085 (2010).
[CrossRef] [PubMed]

J. Zhou, M. Yu, Y. Sun, X. Zhang, X. Zhu, Z. Wu, D. Wu, and F. Li, “Fluorine-18-labeled Gd3+/Yb3+/Er3+ co-doped NaYF4 nanophosphors for multimodality PET/MR/UCL imaging,” Biomaterials 32(4), 1148–1156 (2011).
[CrossRef] [PubMed]

D. K. Chatterjee, A. J. Rufaihah, and Y. Zhang, “Upconversion fluorescence imaging of cells and small animals using lanthanide doped nanocrystals,” Biomaterials 29(7), 937–943 (2008).
[CrossRef] [PubMed]

J. C. Zhou, Z. L. Yang, W. Dong, R. J. Tang, L. D. Sun, and C. H. Yan, “Bioimaging and toxicity assessments of near-infrared upconversion luminescent NaYF4:Yb,Tm nanocrystals,” Biomaterials 32(34), 9059–9067 (2011).
[CrossRef] [PubMed]

Chem. Commun. (Camb.) (2)

S. Jeong, N. Won, J. Lee, J. Bang, J. Yoo, S. G. Kim, J. A. Chang, J. Kim, and S. Kim, “Multiplexed near-infrared in vivo imaging complementarily using quantum dots and upconverting NaYF4:Yb3+,Tm3+ nanoparticles,” Chem. Commun. (Camb.) 47(28), 8022–8024 (2011).
[CrossRef] [PubMed]

L. Y. Wang and Y. D. Li, “Green upconversion nanocrystals for DNA detection,” Chem. Commun. (Camb.) 24(24), 2557–2559 (2006).
[CrossRef] [PubMed]

J. Alloy. Comp. (2)

G. F. Wang, W. P. Qin, J. S. Zhang, L. L. Wang, G. D. Wei, P. F. Zhu, and R. J. Kim, “Controlled synthesis and luminescence properties from cubic to hexagonal NaYF4:Ln3+ (Ln = Eu and Yb/Tm) microcrystals,” J. Alloy. Comp. 475(1-2), 452–455 (2009).
[CrossRef]

C. Sun, F. Yang, T. Cao, Z. You, Y. Wang, J. Li, Z. Zhu, and C. Tu, “Infrared spectroscopic properties of Tm3+, Ho3+:NaY(WO4)2 single crystals,” J. Alloy. Comp. 509(25), 6987–6993 (2011).
[CrossRef]

J. Am. Chem. Soc. (1)

D. Chen, Y. Yu, F. Huang, P. Huang, A. Yang, and Y. Wang, “Modifying the Size and Shape of Monodisperse Bifunctional Alkaline-Earth Fluoride Nanocrystals through Lanthanide Doping,” J. Am. Chem. Soc. 132(29), 9976–9978 (2010).
[CrossRef] [PubMed]

J. Fluor. Chem. (1)

L. L. Wang, C. Y. Cao, X. J. Xue, D. Zhao, D. S. Zhang, K. Z. Zheng, N. Liu, F. Shi, C. F. He, and W. P. Qin, “Effect of crystal structure and ions concentration on luminescence in Yb3+ and Tm3+ codoped fluoride microcrystals,” J. Fluor. Chem. 130(11), 1059–1062 (2009).
[CrossRef]

J. Mater. Chem. (1)

C. Liu, H. Wang, X. Li, and D. Chen, “Monodisperse, size-tunable and highly efficient beta-NaYF4:Yb,Er(Tm) up-conversion luminescent nanospheres: controllable synthesis and their surface modifications,” J. Mater. Chem. 19(21), 3546–3553 (2009).
[CrossRef]

J. Opt. Soc. Am. B (1)

J. Phys. Chem. B (1)

F. Liu, E. Ma, D. Chen, Y. Yu, and Y. Wang, “Tunable Red-Green Upconversion Luminescence in Novel Transparent Glass Ceramics Containing Er: NaYF4 Nanocrystals,” J. Phys. Chem. B 110(42), 20843–20846 (2006).
[CrossRef] [PubMed]

Mater. Lett. (1)

L. L. Wang, H. Chen, D. S. Zhang, D. Zhao, and W. P. Qin, “Dual-mode luminescence from lanthanide tri-doped NaYF4 nanocrystals,” Mater. Lett. 65(3), 504–506 (2011).
[CrossRef]

Nano Lett. (2)

S. F. Lim, R. Riehn, W. S. Ryu, N. Khanarian, C. Tung, D. Tank, and R. H. Austin, “In vivo and scanning electron microscopy imaging of upconverting Nanophosphors in Caenorhabditis elegans,” Nano Lett. 6(2), 169–174 (2006).
[CrossRef]

J. C. Boyer, L. A. Cuccia, and J. A. Capobianco, “Synthesis of colloidal upconverting NaYF4: Er3+/Yb3+ and Tm3+/Yb3+ monodisperse nanocrystals,” Nano Lett. 7(3), 847–852 (2007).
[CrossRef] [PubMed]

Nanoscale (1)

G. Chen, T. Y. Ohulchanskyy, W. C. Law, H. Ågren, and P. N. Prasad, “Monodisperse NaYbF4:Tm3+/NaGdF4 core/shell nanocrystals with near-infrared to near-infrared upconversion photoluminescence and magnetic resonance properties,” Nanoscale 3(5), 2003–2008 (2011).
[CrossRef] [PubMed]

Opt. Commun. (1)

D. Kasprowicz, M. G. Brik, A. Majchrowski, E. Michalski, and P. Gluchowski, “Up-conversion emission in triply-doped Ho3+/Yb3+/Tm3+ KGd(WO4)2 single crystals,” Opt. Commun. 284(12), 2895–2899 (2011).
[CrossRef]

Opt. Express (2)

Phys. Chem. Chem. Phys. (1)

K. Z. Zheng, D. S. Zhang, D. Zhao, N. Liu, F. Shi, and W. P. Qin, “Bright white upconversion emission from Yb3+, Er3+, and Tm3+-codoped Gd2O3 nanotubes,” Phys. Chem. Chem. Phys. 12(27), 7620–7625 (2010).
[CrossRef] [PubMed]

Phys. Rev. B (2)

M. Pollnau, D. R. Gamelin, S. R. Luthi, H. U. Gudel, and M. P. Hehlen, “Power dependence of upconversion luminescence in lanthanide and transition-metal-ion systems,” Phys. Rev. B 61(5), 3337–3346 (2000).
[CrossRef]

M. J. Weber, “Multiphonon relaxation of Rare-Earth Ions in Yttrium Orthoaluminate,” Phys. Rev. B 8(1), 54–64 (1973).
[CrossRef]

Phys. Status Solidi A (1)

P. Huang, F. Liu, D. Chen, Y. Wang, and Y. Yu, “Highly efficient near-infrared to visible upconversion luminescence in transparent glass ceramics containing Yb3+/Er3+:NaYF4 nanocrystals,” Phys. Status Solidi A 205(7), 1680–1684 (2008).
[CrossRef]

Physica B (1)

C. Li, S. Xu, R. Ye, D. Deng, Y. Hua, S. Zhao, and S. Zhuang, “White up-conversion emission in Ho3+/Tm3+/Yb3+ tri-doped glass ceramics embedding BaF2 nanocrystals,” Physica B 406(9), 1698–1701 (2011).
[CrossRef]

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Figures (5)

Fig. 1
Fig. 1

XRD and SEM patterns of sample NaYF4: Yb/Tm/Ho tri-doped NRs with a small amount of cubic NaYF4 (denoted as the red word) and excessive NaF (labeled at the patterns).

Fig. 2
Fig. 2

Under 980 nm excitation, UC emission spectra (a) and luminescence integral intensities corresponding to spectra (b) of NaYF4: 0.2 mol% Yb3+/ x mol% Ho3+/0.005 mol% Tm3+ at the different Ho3+ ion concentrations (x mol% from 0 mol % to 3.5 mol %) recorded at the same conditions. Excitation power density is 200 W/cm2.

Fig. 3
Fig. 3

Under 980 nm excitation, UC emission spectra of NaYF4: Yb3+/Ho3+/Tm3+, NaYF4: Yb3+/Tm3+ (a) and NaYF4: Yb3+/Ho3+ (b) NRs recorded at the same conditions. Excitation power density is 200 W/cm2.

Fig. 4
Fig. 4

Energy level diagrams of Yb3+, Tm3+, and Ho3+ ions and possible UC and ET processes under 980 nm excitation.

Fig. 5
Fig. 5

Excitation power dependence of UC luminescence in NaYF4: 20%Yb3+, 2%Ho3+, 0.5%Tm3+ NRs under 980 nm excitation.

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