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Optics Express

Optics Express

  • Editor: C. Martijn de Sterke
  • Vol. 20, Iss. 7 — Mar. 26, 2012
  • pp: 7602–7607
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Improved 800 nm emission of Tm3+ sensitized by Yb3+ and Ho3+ in β-NaYF4 nanocrystals under 980 nm excitation

Lili Wang, Weiping Qin, Zhenyu Liu, Dan Zhao, Guanshi Qin, Weihua Di, and Chunfeng He  »View Author Affiliations


Optics Express, Vol. 20, Issue 7, pp. 7602-7607 (2012)
http://dx.doi.org/10.1364/OE.20.007602


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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

1. Introduction

Studies on rare earth (RE)-doped UC phosphors have grown rapidly owing to their wide applications in solid-state lasers, three-dimensional flat-panel displays, optical fiber-based telecommunications, low-intensity infrared (IR) imaging, and especially bioprobes and bioimages [1

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

6

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]

]. Compared with the traditionally used biological labels such as various organic dyes, metal complexes, and semiconductor quantum dots, RE-doped fluoride NCs possess excellent luminescent characteristics (large Stoke’s shift, sharp emission peaks, and long fluorescence lifetime, etc), low toxicity, high thermal stability, long durability, neglectable photobleaching, etc [7

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]

]. These characters are attractive for biological imaging applications with multicolor or time-resolved detection [8

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

10

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]

].

The UC processes have been extensively studied in RE-doped fluorides. It is worthwhile to point out that specific UC emissions in NCs can be artificially devised by using different combinations of RE ions at different concentrations [13

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

, 19

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

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]

]. Not only that, UC emissions can be enhanced or quenched by nonradiative ET from one RE ion to another ion. The ion–pair interactions, referred as ET, have been studied widely in the materials doped with Er3+, Eu3+, Tb3+, Ho3+, and Tm3+ ions [21

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]

24

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]

]. For example, white UC fluorescent and 2.0 µm fluorescent emissions in Yb/Ho/Tm tridoped crystals have been extensively investigated under 980 nm excitation [25

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]

28

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]

]. The relevant mechanisms associated with the UC processes have been discussed detailedly. However, few results have been reported on the improved NIR 800 nm UC luminescence of Tm3+ in Yb/Ho/Tm tridoped NaYF4 NCs pumped by a conventional 980 nm NIR light.

In this letter, we presented an observation of enhanced NIR 3H43H6 transition of Tm3+ ions in Yb/Ho/Tm tridoped NaYF4 nanorods (NRs) under 980 nm excitation. Owing to the Ho3+ and Tm3+ ions dopants possess closely spaced energy levels, the complex ET processes between them decreased most emissions of Ho3+ and Tm3+ ions. The distinctly enhanced NIR 800 nm emissions under 980 nm excitation were investigated and the relevant mechanisms associated with the UC processes are discussed here in detail.

2. Experimental

In a typical preparation, 0.6-g NaOH was dissolved in a solution containing oleic acid, ethanol and deionized water (10/5/4, v/v). Then NaF, Y(NO3)3·6H2O, Yb(NO3)3·6H2O, Tm(NO3)3·6H2O and Ho(NO3)3·6H2O were added into the solution under vigorous stirring. The mixture was agitated for 30 min and then transferred into a 50-mL autoclave, sealed, and treated at 180 °C for 19 h. Subsequently, the mixture was allowed to cool to room temperature, and the powder were obtained by centrifuge, rinse and drying [29

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]

].

3. Results and discussion

3.1 Structure and morphology of NaYF4:Yb3+/Ho3+/Tm3+ NCs

To identify the crystallization phase, x-ray-diffraction (XRD) analysis was carried out with a powder diffractometer (Model Rigaku RU-200b), using Ni-filtered CuKα radiation (λ=1.5406 Å). The size and the morphology were characterized by field-emission scanning-electron microscopy (FE-SEM) (Hitchi S-4800). UC emission spectra of the samples were recorded with a fluorescence spectrophotometer (Hitachi F-4500). A power-adjustable laser diode (980 nm, 0-2W) with a lens making the beam parallel was employed as the UC excitation source. The spectra were all recorded under the same conditions (emission slit is 1.0 nm, high voltage of the photomultiplier tube is 400 V, and the excitation power density is about 200 W/cm2).

The XRD pattern depicted in 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).
confirmed the existence of both cubic (JCPDS card 77-2042) and hexagonal phase NaYF4 (JCPDS card 16-0334); in addition, small amounts of NaF were also found in the XRD patterns of the as-prepared NRs. These elementary results indicated that the NaF content has effects not only on the morphology and size but also on the crystal structure of the as-synthesized NRs. The inset in Fig. 1 displays the FE-SEM image of the sample. It is clear that the diameter of NRs is about 100-120 nm and the length is about 700 nm.

3.2 Enhanced NIR 800 nm UC emissions of Tm3+ ions under NIR 980 nm excitation

Figure 2(a)
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.
shows the dependence of the NIR 800 nm UC luminescence spectra of Tm3+ ions on the Ho3+ ion concentration in NaYF4: Yb3+/Ho3+/Tm3+ NRs under 980 nm excitation. For discernible distinction between the spectra at the different doping concentration of Ho3+, luminescence integral intensities corresponding to spectra were shown in Fig. 2(b). With the increase of the Ho3+ ion concentration (mol% from 0% to 3.5%), the luminescence intensities at λ = 800 nm first increase and reach their maximum value at 2%, and then decrease. As can be seen clearly in Fig. 2(b), the luminescence intensity at λ = 800 nm for the NaYF4: 20%Yb3+/2%Ho3+/0.5%Tm3+ NRs is about 3 times higher than that of NaYF4: 20%Yb3+/0.5%Tm3+ NRs. The increased luminescence intensity undoubtedly originates from the sensitization effect of the Ho3+ ions.

Under 980 nm excitation, the NaYF4: Yb3+/Ho3+/Tm3+, NaYF4: Yb3+/Tm3+ and NaYF4: Yb3+/Ho3+ NRs emitted IR-to-UV UC fluorescence, as shown in 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.
. Most emissions of Tm3+ and Ho3+ ions correspond well to what observed with Yb3+/Tm3+ and Yb3+/Ho3+ codoped UC crystals [30

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

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]

]. For discernible distinction between emissions of co-doped and tri-doped NaYF4 NRs, their spectra were shown in Fig. 3(a) and Fig. 3(b), respectively. Figure 3(a) shows the UC luminescence spectra of NaYF4: Yb3+/Ho3+/Tm3+ and NaYF4: Yb3+/Tm3+ NRs. Figure 3(b) shows the UC luminescence spectra of NaYF4: Yb3+/Ho3+/Tm3+ and NaYF4: Yb3+/Ho3+ NRs. Owing to the Ho3+ and Tm3+ ions dopants possess closely spaced energy levels, the changes of peaks intensity corresponding to different levels are different due to the complex ET processes as shown in Fig. 3.

3.3. UC and ET mechanisms for Tm3+ and Ho3+ions

Figure 4
Fig. 4 Energy level diagrams of Yb3+, Tm3+, and Ho3+ ions and possible UC and ET processes under 980 nm excitation.
shows the energy level diagrams of Yb3+, Tm3+, Ho3+ and as well as the possible upconverted process [30

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]

, 32

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]

]. Under NIR laser excitation, Yb3+ ions continuously absorbed 980 nm photons and transfer the energy to populate the states of 3H5, 3F2 (3F3), 1G4, 1D2, 1I6, 3PJ of Tm3+ and 5I6, 5F2/5F4, 5F2/3F2/5G2 of Ho3+ in turn, as described in Ref [31

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]

]. As mentioned above, the most important mechanism for the enhancement of 800 nm luminescence is the ET between excited Tm3+ and Ho3+ ions. Three possible ET processes should be considered for their appropriate energy matching: ET1 3F43H6 (Tm3+): 5I85I7 (Ho3+), ET2 5I65I8 (Ho3+): 3H63H5 (Tm3+), and ET3 5I45I8 (Ho3+): 3H63H4 (Tm3+). All the three ET processes are responsible for improving the population of 3H4 level of Tm3+ as follows. The population of 5I7 level of Ho3+ is improved while the population of 3F4 level of Tm3+ is decreased through ET1 process. The 5I7 level of Ho3+ has more energy to absorb a photon from Yb3+ to populate the 5F5 level of Ho3+. This can be confirmed from the undiminished spectra of 5F55I8 (Ho3+) transition before and after doping of Tm3+ in Fig. 3(b). Then, most of the population of 5F5 level of Ho3+ relax rapidly to the 5I4 level. Some of Tm3+ in the 3H4 state can be populated through the ET3, and a small proportion of Ho3+ in 5I4 level relax rapidly to the 5I5 level which will decreased the population process 5I55F3,2 (Ho3+). The intensity of 5S2/5F45I8 (Ho3+) emission decreased as shown in Fig. 3(b). Otherwise, the population of 3H5 state of Tm3+ can be increased and that of 5I6 state of Ho3+ can be decreased through ET2, resulting in the enhancement of 800 nm emission. Especially, the intensity of 1D23H6 emission were quenched much compared to that of 1G43H6 emission of Tm3+ as shown in Fig. 3(a), owing to the abundant levels of Ho3+ around the energy height of 1D2 level of Tm3+ named as ET4.

To understand the ET processes well, we investigated the excitation power dependence of UC luminescence intensities. For an unsaturated UC process, the integrated UC luminescence intensity If is proportional to Pn [33

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]

], where P is the pumping laser power, and n is the number of laser photons required in populating the upper emitting state. Figure 5
Fig. 5 Excitation power dependence of UC luminescence in NaYF4: 20%Yb3+, 2%Ho3+, 0.5%Tm3+ NRs under 980 nm excitation.
shows the typical pump-power dependence of UC luminescence of NaYF4: 20%Yb3+, 2%Ho3+, 0.5%Tm3+. The values of photon number n were 1.93 ± 0.04 for 642.2 nm (5F55I8 of Ho3+) and 1.98 ± 0.01 for 800 nm (3H43H6 of Tm3+) emissions, respectively, indicating that these transitions were of two-photon UC processes. Power dependence analyses illustrate that the 3H4 level of Tm3+ has the same multi-photon UC character with the 5F5 and 5I4 levels of Ho3+ ions and confirm that it is populated by the ETs from the corresponding levels of Ho3+ ions.

4. Conclusions

In conclusion, Yb3+/Ho3+/Tm3+ tridoped NaYF4 NRs were successfully synthesized using a simple wet-chemical route. Particularly, the introduction of Ho3+ into the Tm3+/Yb3+ co-doped NaYF4 NRs resulted in a significant increase in UC efficiency of 800 nm emission of Tm3+, which was suitable for all the advanced synthesis methods of ultrasmall (with size of less than 10 nm) monodisperse NCs. We offer a fast, simple, inexpensive, and highly reproducible approach for the synthesis of NIR-NIR UC NCs.

Acknowledgment

This work was supported by the National Natural Science Foundation of China (NNSFC) (grants 60908031, 60908001, 61077033, 51072065 and 61178073).

References and links

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]

OCIS Codes
(190.4180) Nonlinear optics : Multiphoton processes
(300.6340) Spectroscopy : Spectroscopy, infrared

ToC Category:
Spectroscopy

History
Original Manuscript: February 14, 2012
Revised Manuscript: March 7, 2012
Manuscript Accepted: March 8, 2012
Published: March 19, 2012

Virtual Issues
Vol. 7, Iss. 5 Virtual Journal for Biomedical Optics

Citation
Lili Wang, Weiping Qin, Zhenyu Liu, Dan Zhao, Guanshi Qin, Weihua Di, and Chunfeng He, "Improved 800 nm emission of Tm3+ sensitized by Yb3+ and Ho3+ in β-NaYF4 nanocrystals under 980 nm excitation," Opt. Express 20, 7602-7607 (2012)
http://www.opticsinfobase.org/oe/abstract.cfm?URI=oe-20-7-7602


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References

  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, 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, 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, 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, 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, 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, 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, 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, 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, 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, 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, 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, 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, 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, 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, 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, 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, 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, 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, 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, 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, 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, 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, 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, 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, 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, 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, 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, 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, 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, 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, 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, M. P. Hehlen, “Power dependence of upconversion luminescence in lanthanide and transition-metal-ion systems,” Phys. Rev. B 61(5), 3337–3346 (2000). [CrossRef]

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