PL Properties of (Ba, Ca)₂( Si, P)O₄: Eu Synthesized by Various Annealing and Cooling Process

Abstract:

We have been investigating the series of P doped Ca₂SiO₄ (C₂S) using Eu²⁺ or Eu³⁺ as activator with various colors. The crystal structure of C₂S is particularly easily controlled by heating because the established polymorphs of C₂S are, in the order of increasing temperature, γ, β, α’_L, α’_H, and α. In order to control the crystal structure, the phosphors were synthesized and then annealed at temperatures 1473 K-1773 K. The crystal structures and PL properties were compared between slow cooling and quenching (cooled in water). We found unique phenomena when the phosphors were treated by quenching process. In the case of (Ba_1-xCa_x)₂(Si_0.94P_0.06)O₄:Eu³⁺ ( 0.25 ≤ x ≤ 1), color emission changed from red to blue-white for the phosphor with a high concentration of Ba and quenched at 1773 K. In general, Eu³⁺ doped phosphors showed the red emission color in any host materials. However, Ba-included and quenched-treatment phosphors emitted a bright white color. The mechanism and relationship between the PL property and crystal structure were characterized carefully using X-ray diffraction, electron microscope and X-ray absorption fine structure.

• Periodical: Materials Science Forum (Volume 1016)
• Pages: 231-235
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.1016.231
• Online since: January 2021
• Authors: Shota Ando*, Hiromi Nakano, Koichiro Fukuda
• Keywords: Annealing, Crystal Structure, Photoluminescence, Quenching, Slow Cooling

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