Single Crystal Growth and Crystal Structure Analysis of Novel Orange-Red Emission Pure Nitride CaAl2Si4N8:Eu2+ Phosphor

Shota Hasegawa; Takuya Hasegawa; Sun Woog Kim; Ryota Yamanashi; Kazuyoshi Uematsu; Kenji Toda; Mineo Sato

doi:10.1021/acsomega.9b00606

Single Crystal Growth and Crystal Structure Analysis of Novel Orange-Red Emission Pure Nitride CaAl₂Si₄N₈:Eu²⁺ Phosphor

ACS Omega. 2019 Jun 7;4(6):9939-9945. doi: 10.1021/acsomega.9b00606. eCollection 2019 Jun 30.

Authors

Shota Hasegawa¹, Takuya Hasegawa², Sun Woog Kim³, Ryota Yamanashi¹, Kazuyoshi Uematsu¹, Kenji Toda¹, Mineo Sato¹

Affiliations

¹ Graduate School of Science and Technology and Department of Chemistry and Chemical Engineering, Niigata University, 8050, Igarashi 2-Nocho, Nishi-ku, Niigata 950-2181, Japan.
² Center for Advanced Marine Core Research, Kochi University, Nankoku 783-8502, Japan.
³ Electronic Convergence Division, Optic and Electronic componemt Materials Center, Korea Institute of Ceramic Engineering and Technology, 101 soho-ro, Jinju-si 52851, Republic of Korea.

Abstract

Single crystal of novel orange-red emission CaAl₂Si₄N₈:Eu²⁺ phosphor was grown by our original vapor phase technique, and the precise crystal structure was investigated for the first time by single crystal X-ray diffraction analysis. The crystal structure of CaAl₂Si₄N₈:Eu²⁺ single crystal was verified to be an α-Si₃N₄-type trigonal structure (space group P31c) with a = 0.79525(9) nm, c = 0.57712(8) nm, and z = 2. The Ca atoms were coordinated to seven nitrogen atoms and located in the three-dimensional framework formed by (Al, Si)N₄ tetrahedra. The single-crystal CaAl₂Si₄N₈:Eu²⁺ phosphors exhibited a broad reddish-yellow emission with a peak at 600 nm under near-UV and blue light excitation. When increasing the temperature up to 150 °C, the emission intensity of the CaAl₂Si₄N₈:Eu²⁺ phosphor decreased to 88% of the initial value at 25 °C.