Silica Encapsulation of SrAl₂O₄:Eu²⁺, Dy³⁺ Phosphors by Sol-Gel Method

Abstract:

SrAl₂O₄:Eu²⁺,Dy³⁺ phosphors were synthesized under different temperature by high temperature solid phase method. Encapsulation modification of SrAl₂O₄:Eu²⁺,Dy³⁺ by using SiO₂ glycol were made over chemically unstable against water. Photoluminescence measurement result shows that when the sintering temperature is 1300 °C, the initial afterglow brightness of SrAl₂O₄:Eu²⁺,Dy³⁺ is up to the highest, 12101 mcd/m². FTIR results showed that new IR peaks at 1085 cm⁻¹ due to the vibration of Si-O-Si and at 931cm⁻¹ due to the vibration of Si-O-Al appeared after silica encapsulation. This verified that the silica encapsulation is not only a physical absorption process but also involving chemical bonding process. Both phosphors before and after encapsulation have same emission peak at 510 nm. A dense layer of silica formed on phosphor surface has the highest water-resistance after being encapsulated for 2h under the condition of pH 4 and encapsulation amount 10:1. The pH value of aqueous solution contained phosphor was steadily 8, and the initial afterglow brightness decreased only by 9%, that is, from 12101 to 11011 mcd/m².

• Periodical: Key Engineering Materials (Volume 680)
• Pages: 224-227
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.680.224
• Online since: February 2016
• Authors: Huan Wang, Xiao Ping Liang*, Kai Liu, Qian Qian Zhou, Jun Wang, Peng Chen, Ben Qiao He, Jian Xin Li
• Keywords: Dy³⁺, Encapsulation, Silica, Sol-Gel Method, SrAl₂O₄:Eu²⁺

References

[1] J Jang, S Han, S. E. Chung, Development of conformal phosphor coating technique for light-emitting diodes using image-processing-based maskless lithography, Microelectron. Eng. 118 (2014) 11-14.

DOI: 10.1016/j.mee.2014.01.006

[2] L.G. C, A. D, S. G, Thermal and luminous investigations of a pcLED based refrigerating liquid prototype, Appl. Therm. Eng. 70 (2014) 884-891.

DOI: 10.1016/j.applthermaleng.2014.06.008

[3] N. J, A. T, H. J, et al, Effect of boron substitution on the preparation doped strontium aluminates, J. Alloys compd. 374 (2004) 108-111.

[4] S. M Bai, J Wang, H. L. Miao, et al, Luminescence Properties of the Y3-x-yPrxGdyAl5O12: Ce3+ Phosphors for White Light Emitting Diodes, Acta Optica. Sinica. 30 (2010) 1402-1405.

DOI: 10.3788/aos20103005.1402

[5] X.D. Lü, Silica encapsulation study on SrAl2O4: Eu2+, Dy3+ phosphors, Mater. Chem. Phys. 93 (2005) 526-530.

DOI: 10.1016/j.matchemphys.2005.04.002

[6] X. D Lü, M. J Zhong, W. G Shu, Alumina encapsulated SrAl2O4: Eu2+, Dy3+ phosphors, Powder Technol. 177 (2007) 83-86.

DOI: 10.1016/j.powtec.2007.03.010

[7] N. L Hom, W. Takanori, T. Toshio, Highly water resistant surface coating by fluoride on long persistent Sr4Al14O25: Eu2+/Dy3+ phosphor, Appl. Surf. Sci. 256 (2010) 2347-2352.

DOI: 10.1016/j.apsusc.2009.10.065

[8] P.T. Ji, X.Y. Chen, Y.Q. Wu, Encapsulating MAl2O4: Eu2+, Dy3+(M= Sr, Ca, Ba) phosphors with triethanolamine to enhance water resistance, Appl. Surf. Sci. 258 (2011) 1888-1893.

DOI: 10.1016/j.apsusc.2011.10.098

[9] L. Li, J. Ji, R. Fei, A Facile Microwave Avenue to Electrochemiluminescent Two-Color Graphene Quantum Dots, Adv. Funct. Mater. 22(2012) 2971–2979.

DOI: 10.1002/adfm.201200166

[10] H.Z. Zhang, X.D. Wang, D.Z. Wu, Silica encapsulation of n-octadecane via sol-gel process: A novel microencapsulated phase-change material with enhanced thermal conductivity and performance, J. Colloid Interface Sci. 343 (2010) 246-255.

DOI: 10.1016/j.jcis.2009.11.036

[11] Y. Zhu, M.T. Zheng, J.H. Zeng, et al. Luminescence enhancing encapsulation for strontium aluminate phosphors with phosphate, Mater. Chem. Phys. 113 (2009) 721-726.

DOI: 10.1016/j.matchemphys.2008.08.007