Rare doped fluorides

Active optical properties of rare-earth-doped fluoride glasses... 

Little basic research has been devoted to Yb3+ ion itself which possesses only one excited state [151]. However, as shown previously, this ion is of special interest for a number of energy transfer and up-conversion processes, which take advantage of the strong 2F7/2 — 2F5/2 absorption band of Yb3+. In addition, efficient lasing around 1.02 can be obtained with this ion and laser cooling effects have been observed. These points are developed in the next section devoted to applications of rare-earth-doped fluoride glasses. 

Rare-earth-doped fluoride glasses are suitable for some other specific applications that require laser transitions at wavelengths greater than 2 pm, efficient up-conversion mechanisms or ultra-high quantum efficiencies. 

Rare-earth fluorides are good fluorine-ion conductors (see sect 5.2). Addition of aliovalent cations significantly increases the fluorine-ion conductivity even fiulher. For example, single crystals of Lap3 doped with Eup2 are widely used in commercial apphcations of ion-selective electrodes (ISE) as specific electrodes (Frant and Ross 1966). In the field of ISE, only the pH-sensing glass electrode is more widely used. Fluoride-ion detection is important in sea water, water minerals, rocks, fossils and minerals, biomedical applications, potable water and plant and animal metabolism. 

Murtagh, M.T., Sigel Jr., G.H., Fajardo, J.C., Edwards, B.C., Epstein, R.I., 1999b. Laser-induced fluorescent cooling of rare-earth-doped fluoride glasses. J. Ntm-Cryst. Solids 253 (1 3), 50 57. 

Ballato J., Dejneka M., Riman R.E., Snitzer E., Zhou W. Sol-gel synthesis of rare-earth-doped fluoride glass thin films. J. Mater. Res. 1996 11 841-849 Banks E., Srivastava A.M. Concentration and temperature dependence of divalent europium line emission in BaMgF. J. Electrochem. Soc. 1987 134 1568-1570 Biswas A., Maciel G.S., Friend C.S., Prasad P.N. Upconversion properties ofa transparent Er -Yb co-doped Lap3-Si02 glass-ceramics prepared by sol-gel method. J. Non-Cryst. Solids 2003 316 393-397... 

Fujiura K, Nishida Y, Kanamori T, Teranuma Y, Hoshino K, Nakagawa K, Ohishi Y, Sudo S. Reliability of rare-earth-doped fluoride fibers for optical fiber amplifier application. IEEE Photonics Technology Letters, vol.lO, no.7, pp.946-8. July 1998. 

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

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)...

Lanthanum oxyhalides including LaOF doped with luminescent rare-earth ions were studied as phosphors for potential applications in the earlier times [82]. Crystal structures and optical or luminescent properties of rare-earth oxyfluoride compounds were extensively investigated in the 1990s [81-87]. Usually, rare-earth doped oxyfluoride materials are synthesized by heat treatments of rare-earth fluorides in the air [88] or mixtures of rare-earth oxides and NH4F in N2 atmosphere [89]. 

J. Ballato, M. Dejneka, E. Snitzer, R.E. Riman, W. Zhou, Sol-gel of rare-earth-doped fluoride glass thin films, J. Mater. Res., 11, 841-849 (1996). 

Y. Miyajima, T. Komukai, T. Sugawa and T. Yamamoto, Rare earth-doped fluoride fibre amplifiers and fibre lasers. Opt. Fibre Technol., 1, 35-47 (1994). 

Jacobsohn L. G., C. J. Kucera, T. L. James, K. B. Sprinkle, J. R. DiMaio, B. Kokuoz, B. Yazgan-Kukouz, T. A. DeVol and J. BaUato, Preparation and Characterization of Rare Earth Doped Fluoride Nanoparticles, Materials, 3, 2053-2068 (2010). 

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