Study of Luminescent Properties of CaNb₂O₆:Yb, Er, Tm

We used solid phase synthesis at 1200 °C to create a luminophore based on CaNb₂O₆ and activated by ytterbium, erbium, and thulium ions. We present X-ray phase analysis results for the CaNb₂O₆:Yb, Er, Tm compound. The X-ray diffraction patterns obtained do not contain reflexes belonging to the intermediate phases. We investigated spectral properties of a calcium niobate-based luminophore upon excitation by a 940 nm laser. There are bands in the visible and IR regions to be found in the luminescence spectra. The up-conversion (anti-Stokes emission) luminescence spectrum comprises three bands peaking at 560, 676 and 807 nm. In the IR range, there are three peaks to be detected in the luminescence spectrum at 1010, 1540 and 1812 nm. We established the luminescence variation patterns for compounds based on CaNb₂O₆:Yb, Er, Tm. We determined the optimum Tm³⁺ concentration in the system that makes it possible to achieve the highest luminescence efficiency in the 1640--2000 nm range peaking at 1812 nm. We considered an energy transfer mechanism involving Yb³⁺ and Er³⁺ as luminescence stabilisers in a thulium ion. Employing erbium as an additional sensitiser allowed the luminescence intensity in the 1812 nm band to be increased by 1.5 time

References

[1] Cummings J.P., Srmonsen S.H. The crystal structure of calcium niobate (CaNb₂O₆). Am. Miner., 1970, vol. 55, no. 1-2, pp. 90--97.

[2] Singh K.N., Bajpai P.K. Synthesis, structural, dielectric and electrical impedance study of CaNb₂O₆ phase pure material. Int. J. Phys. Sci., 2010, vol. 14, no. 4, pp. 501--510.

[3] Cho I.S., Bae S.T., Kim D.H., et al. Effects of crystal and electronic structures of ANb₂O₆ (A = Ca, Sr, Ba) metaniobate compounds on their photocatalytic H₂ evolution from pure water. Int. J. Hydrog. Energy, 2010, vol. 35, iss. 23, pp. 12954--12960. DOI: https://doi.org/10.1016/j.ijhydene.2010.04.057

[4] Ballman A.A., Porto S.P.S., Yariv A. Calcium niobate Ca(NbO₃)₂ --- a new laser host crystal. J Appl. Phys., 1963, vol. 34, no. 11, pp. 3155--3156. DOI: https://doi.org/10.1063/1.1729154

[5] Li K., Liu X., Zhang Y., et al. Hostsensitized luminescence properties in CaNb₂O₆:Ln³⁺ (Ln³⁺ = Eu³⁺/Tb³⁺/Dy³⁺/Sm³⁺) phosphors with abundant colors. Inorg. Chem., 2015, no. 54, no. 1, pp. 323--333. DOI: https://doi.org/10.1021/ic502493c

[6] Li J.H., Lui X.H., Wu J.B. Efficient diodeendpumped Yb:CaNb₂O₆ thindisk laser at 1003 nm and secondharmonic generation for an emission at 501.5 nm. Laser Phys. Lett, 2012, vol. 9, no. 3, pp. 199--203. DOI: https://doi.org/10.1002/lapl.201110118

[7] Cao R., Qin Z., Jiang S., et al. Enhanced emission of CaNb₂O₆:Sm³⁺ phosphor by codoping Na⁺/B³⁺ and the emission properties. Bull. Mater. Sci., 2016, vol. 39, iss. 1, pp. 187--193. DOI: https://doi.org/10.1007/s1203401511280

[8] Zhou R., Wei X., Duan C., et al. Intense bluegreen cooperative luminescence from Yb³⁺ pairs within CaNb₂O₆ matrix. ECS J. Solid State Sci., 2012, vol. 1, no. 6, pp. 147--152. DOI: https://doi.org/10.1149/2.014206jss

[9] Li N., Wang W., Duan W., et al. Upconversion luminescence of Ho³⁺/Yb³⁺ co-doped CaNb₂O₆ thin films. Chem. Phys. Lett., 2016, vol. 644, pp. 152--156. DOI: https://doi.org/10.1016/j.cplett.2015.11.041

[10] Wang Y., Duan P., Li N., et al. Structure and properties of Dy³⁺-doped CaNb₂O₆ nanophosphors. J. Comput. Theor. Nanosci., 2015, vol. 12, no. 9, pp. 2648--2651. DOI: https://doi.org/10.1166/jctn.2015.4157

[11] Blasse G., van Leur M.G.J. Luminescence and energy transfer in the columbite structure. Mater. Res. Bull., 1985, vol. 20, iss. 9, pp. 1037--1045. DOI: https://doi.org/10.1016/0025-5408(85)90202-8

[12] McAlister W.A. Rare-Earth activated niobates. J. Electrochem. Soc., 1984, vol. 131, no. 5, pp. 1207--1211. DOI: https://doi.org/10.1149/1.2115779

[13] Blasse G., Grabmaier B.C. Luminescent materials. Springer, 1994.

[14] Blasse G., Corsmit A.F. Electronic and vibrational spectra of ordered perovskites. J. Solid State Chem., 1973, vol. 6, iss. 4, pp. 513--518. DOI: https://doi.org/10.1016/S0022-4596(73)80008-8

[15] Mateos L., Garcia-Santizo J.V., Molina P., et al. Infrared to visible up conversion energy transfer confined at ordered micro-ring structures. Opt. Mater., 2012, vol. 34, iss. 12, pp. 2035--2040. DOI: https://doi.org/10.1016/j.optmat.2012.03.013

[16] Vorobyev V.A., Ledeneva E.A. [Study on effect of ytterbium and erbium impurities on the luminescence of CaNb₂O₆ [Technical Sciences: Problems and Solutions. Proc. VI Int. Pract. Conf.]. Moscow, Internauka Publ., 2017, pp. 130--136 (in Russ.).