Ce-Doped La3Si6.5Al1.5N9.5O5.5, a Rare Highly Efficient Blue-Emitting Phosphor at Short Wavelength toward High Color Rendering White LED Application

Chun Yun Wang, Takashi Takeda, Otmar Melvin Ten Kate, Masataka Tansho, Kenzo Deguchi, Kohsei Takahashi, Rong Jun Xie, Tadashi Shimizu, Naoto Hirosaki

Research output: Contribution to journalArticleScientificpeer-review

33 Citations (Scopus)

Abstract

Phase pure nondoped and Ce doped La3Si6.5Al1.5N9.5O5.5 (Al containing La N-phase) samples have been obtained by solid-state reaction synthesis for the first time. 1% Ce-doped La3Si6.5Al1.5N9.5O5.5 phosphor displays a broad excitation band ranging from UV to 410 nm, with a maximum at 355 nm. UV light excitation results in a narrow Ce3+ 5d-4f emission band (fwhm = 68 nm) centered at 418 nm. The emission can be tuned from 417 nm at 0.5% Ce to 450 nm at 50% Ce. A high internal quantum efficiency up to 84% is achieved for a 1% Ce doped sample, which has CIE chromaticity coordinates of x = 0.157 and y = 0.069, close to the NTSC blue standard (x = 0.155; y = 0.070). Compared to La3Si8O4N11:Ce phosphor, the quantum efficiency and thermal stability have been enhanced for La3Si6.5Al1.5N9.5O5.5:Ce phosphor without shifting the emission peak wavelength. La3Si6.5Al1.5N9.5O5.5:Ce shows less thermal quenching than La3Si8O4N11:Ce and no shift or change in the shape of emission spectra with increasing the temperature from 4 to 573 K. These results show that La3Si6.5Al1.5N9.5O5.5:Ce is more efficient than any other (oxy-)nitride phosphor with an emission in the short wavelength blue region (400-450 nm). A white LED was fabricated using the La3Si6.5Al1.5N9.5O5.5:5%Ce as a blue phosphor. The high color rendering index (Ra = 93.2, R9 = 91.4, and R12 = 89.5) obtained shows that the phosphor is a very promising conversion phosphor for white LEDs.

Original languageEnglish
Pages (from-to)22665-22675
Number of pages11
JournalACS Applied Materials and Interfaces
Volume9
Issue number27
DOIs
Publication statusPublished - 12 Jul 2017

Keywords

  • deep blue
  • high color rendering
  • high efficiency
  • LaSiAlNO:Ce
  • luminescence
  • sialon
  • white LED

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    Wang, C. Y., Takeda, T., Ten Kate, O. M., Tansho, M., Deguchi, K., Takahashi, K., Xie, R. J., Shimizu, T., & Hirosaki, N. (2017). Ce-Doped La3Si6.5Al1.5N9.5O5.5, a Rare Highly Efficient Blue-Emitting Phosphor at Short Wavelength toward High Color Rendering White LED Application. ACS Applied Materials and Interfaces, 9(27), 22665-22675. https://doi.org/10.1021/acsami.7b03909