| Novel Oxide Phosphor Materials Synthesized by Melt Synthesis Method |
| Sun Woog KIM |
| Niigata University |
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Recent years, the phosphor materials based on nitrides and oxynitrides have been usually used the commercial white LEDs phosphors because of their high chemical and thermal stabilities. In particular, yellow- and red-emitting nitrides phosphors have received much attention for the white LED applications. However, these nitride phosphors require a special high-temperature and high-pressure furnace for synthesis of a single phase form and expensive raw materials, which contribute to increase the cost of white LEDs. Therefore, investigations have been devoted to search for novel phosphors based on oxide materials, which can be synthesized in a single phase form and can show high luminescence efficiency under near-UV and blue light excitation.
We proposed melt synthesis technique using arc-imaging furnace as a new synthesis method to develop novel white LED phosphors. Arc-imaging furnace can be heated rapidly the samples at various atmospheres up to high temperatures even greater than 2000 ¨¬C, and also rapidly cooled by removing the sample stage from the mirror¡¯s focus. In addition, the melt reaction is extremely rapid and homogeneous than that of a conventional solid-state reaction method because of liquid mixing and rapid diffusion in the liquid phase [1,2]. Therefore, the melt synthesis technique using arc-imaging furnace is suitable for rapid screening of novel LED phosphors. Furthermore, we have previously demonstrated that this method is suitable to synthesize the oxide materials having metastable phase in the room temperature and it is also suitable for synthesizing glass materials because this method has rapid cooling process [3-5].
In this study, we present the availability of the melt synthesis technique using arc-imaging furnace and the optical properties of the novel phosphor materials obtained by this method.
References:
[1] T. Ishigaki, N. Matsushita, M. Yoshimura, K. Uematsu, K. Toda, and M. Sato, Phys. Procedia, 2 (2009) 578.
[2] T. Ishigaki, M. Yoshimura, N. Matsushita, K. Uematsu, K. Toda, and M. Sato, J. Eur. Ceram. Soc., 30 (2010) 165.
[3] S. W. Kim, T. Hasegawa, T. Ishigaki, K. Uematsu, K. Toda, and M. Sato, ECS Solid State Lett., 2 (2013) R49.
[4] H. Nakagawa, S. W. Kim, K. Uematsu, T. Ishigaki, K. Toda, H. Takaba, and M. Sato, Abstract of 8th Int. Conf. Sci. Technol. for Advanced Ceramics (2014), 25pHO02.
[5] S. W. Kim, T. Hasegawa, M. Inoue, T. Ishigaki, K. Uematsu, K. Toda, and M. Sato, J. Ceram. Soc. Jpn., 122 (2014) 452.
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| Acknowledgements : This work was supported by a project from NEDO, New Energy and Industrial Technology Development Organization (Rare Metal Substitute Materials Development Project Development of Technology for Reducing Tb and Eu Usage in Phosphors for Fluorescent Lamp by High-speed Material Synthesis and Evaluation). |
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