Synthesis, Crystal Structure, and Photoluminescence of Sr‐α‐SiAlON:Eu ²⁺

Sr‐containing α‐SiAlON (Sr m /2 Si 12‐ m – n Al m + n O n N 16– n :Eu 2+ ) phosphor was obtained as a major phase in compositions having small m and n values, by firing the powder mixture of SrSi 2 , SrO, α‐Si 3 N 4 , AlN, and Eu 2 O 3 at 2000°C for 2 h under 1 MPa nitrogen atmosphere. The crystal structure of Sr‐α‐SiAlON was refined by the Rietveld analysis of the synchrotron X‐ray powder diffraction pattern. The crystal structure showed that the Sr–N2 bonding distance of Sr‐α‐SiAlON was fairly large compared with that of Ca‐α‐SiAlON. The displacement of N2 sites probably allow the interstices in α‐SiAlON to accommodate the introduction of the large Sr ion. Sr‐α‐SiAlON:Eu 2+ phosphor has an excitation wavelength ranging from the ultraviolet region to 500 nm and emits a strong yellow light.