Temperature dependence of Ce:YAG single-crystal phosphors for high-brightness white LEDs/LDs

Stelian Arjoca, Encarnación G. Víllora, Daisuke Inomata, Kazuo Aoki, Yoshiyuki Sugahara, Kiyoshi Shimamura

Research output: Contribution to journalArticle

49 Citations (Scopus)

Abstract

The growth of Ce:Y3Al5O12(Ce:YAG) single-crystal phosphors (SCPs) by the Czochralski technique is analyzed in terms of segregation coefficient, solubility and absorption cross-section. The emission characteristics of these SCPs are investigated in a wide temperature range, from liquid He temperature up to 500 °C. The internal quantum efficiency of SCPs achieves its maximum at about 250 °C. Thermal quenching of SCPs at high temperature is attributed to the Mott-Seitz mechanism. In the case of ceramic powder phosphors, a continuous droop is observed with the temperature due to defectrelated non-radiative recombination paths. It is shown that (Ce:YAG SCPs + blue LEDs/LDs) can cover a wide range of color temperatures 5500-7000 K, with color rendering indices around 70. In conclusion, it is shown that Ce:YAG SCPs are the most efficient and temperature stable converters to fabricate high-brightness white light sources with high-power blue LEDs and LDs.

Original languageEnglish
Article number055503
JournalMaterials Research Express
Volume2
Issue number5
DOIs
Publication statusPublished - 2015 May

Keywords

  • Ce-doped garnets
  • Quantum efficiency
  • Single-crystal phosphors
  • White LEDs/LDs

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Biomaterials
  • Surfaces, Coatings and Films
  • Polymers and Plastics
  • Metals and Alloys

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