Up-conversion luminescence

It is also possible to obtain luminescence at photon energies higher than the absorbed photon energy. This is called anti-Stokes or up-conversion luminescence and it occurs for multilevel systems, as in the example shown in Figure 1.11. For this... 

The Y202S Yh, Er nanotubes reported by Li et al. showed red up-conversion luminescence at 650 nm, assigned to the F9/2 I15/2 transition. Dovm-conversion emission occurred when these nanotubes were excited with 310 nm Xe sources. Additionally, there was a broad emission band centered at 730 nm in both up- and dovm-conversion spectra, assumed to be the 15/2 transition (Wang and Li, 2003). Tm-doped Y2O2S up-conversion NPs emitted blue photons (with X at ca. 475 nm) that came from G4 F4 transition, and also emitted red photons aroimd 650 and 690 nm (Hirai and Orikoshi, 2004 Fires et al., 2004). Y202S Ho up-conversion NPs showed intense green emission related to the S2, F4 Is transitions of Ho. The red emission from the F5 Is transition was relatively weak (Hirai and Orikoshi, 2004). 

Yu, M.X., Li, F.Y., Chen, Z.G, et al. (2009) Laser scanning up-conversion luminescence microscopy for imaging cells labeled with rare-earth nanophosphors. Analytical Chemistry, 81, 930-935. 

C.G. Dou, Q.H. Yang, X.M. Hu, J. Xu, Cooperative up-conversion luminescence of ytterbium doped yttrium lanthanum oxide transparent ceramic, Optics Communications, 281, 692-5 (2008). 

Chen, D.Q., Yu, Y.L., Huang, F., Yang, A.P., Wang, Y.S., 201 Id. Lanthanide activator doped NaYhi (Gd (F4nanocrystals with tunable down-, up-conversion luminescence and paramagnetic properties. J. Mater. Chem. 21, 6186—6192. 

Wang NL, Zhang XY, Jiang HT, Dong TT, Yang D (2012) Fabrication of Er /Yb co-doped Y2O3 transparent ceramics by solid-state reaction method and its up-conversion luminescence. Mater Chem Phys 135 709-713... 

Hou XR, Zhou SM, Jia TT, Lin H, Teng H (2011) Investigation of up-conversion luminescence properties of REATj co-doped Y2O3 transparent ceramic (RE = Er, Ho, Pr, and Tm). Phys B-Condens Matter 406 3931-3937... 

Up-Conversion Luminescent Switch Based on the Combination of DTE and Rare-Earth Nanophosphors... 

Fig. 3 UV-visible absorption spectra of DTE-BMes2/LaF3 Yb, Ho-loaded PMMA film before (dashed line) and after (solid line) irradiati(Hi with 365 nm light for 30 min, and the normalized up-conversion luminescence spectra of the prepared film (dotted line, 4exc = 980 nm). Inset shows the image of the up-conversion emission of the film. (Reprinted with permission from [48])...

Figure 33 Principle and confocal luminescence images of the up-conversion luminescent switch consisting of l/LaF3 Yb,Ho-loaded PMMA film. Before (left), and after (right) irradiation with 365 nm light for 30 min, A-ex = 980 nm. (Reproduced by permission of The Royal Society of Chemistry from Ref. 77. http //dx.doi.org/10.1039/B809021A)...

Fig. 8.3 Photograph for up-conversion luminescence of rare earth-doped fluoride nanocrystals dispersed in (3-triethoxysilyl) propyl-3-methylimidazolium chloride under the excitation wavelength of 980 tun from left to right, NaYF4 Yb "/Er "(20, 2 mol%), NaYF4 Yb /Tm (20,2 mol %), BaYF5 Yb /Ei (20, 2 mol%), BaYFsrYb /Tm " (20, 2 mol%) (Reproduced from Ref. [46] with permission from John Wiley and Sons)...

Yan Z, Yan B, Jia L (2014) Hydrogels immobilized by doped rare earth fluoride nanocrystals ionic liquid dispersion and down/up-conversion luminescence. Spectra chim Acta A 121 732-736... 

Figure 15. Up-conversion luminescence spectra of BErT and BYET thin films on fused silica substrates pumped by 980 nm. From Ref [70] Gao, F., et al., J. Appl. Phys., 106, 126104 (2009). Copyright American Institute of Physics (2009)...

As is known, Er Afb co-doped materials have been recognized as one of the most efficient systems for obtaining frequency up-conversion photoluminescence due to the efficient energy transfer from Yb to Er ions pmnped by 980 nm [68,69], in which Er ions acted as luminescence centers and Yb ions as sensitizers. On the other hand, considering the lattice structure of BiT, Er AT) ions can be accommodated in well defined sites of BiT lattice by substituting for Bi ions without the need of charge compensation. Therefore, it is of much interest to study up-conversion luminescence properties of Ei /Yb co-doped BiT thin films [70]. 

G. Dantelle, M. Mortier, D. Vivien, G. Patriarche, Effect of CeFs on the nulceation and up-conversion luminescence in transparent oxyfluoride glass-ceramics, Chem. Mater. 17, 2216-2222 (2005). 

J. Qui, A. Makishima, Y. Kawamoto, Efficient blue up-conversion luminescence of Tm " " in transparent oxyfluoride glass ceramics containing Cdi xPb,F2 nanocrystals, J. Phys. Cond. Matter 41, 13827-13834(2002). 

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