Enhancement of Mechanoluminescence in CaAl[sub 2]Si[sub 2]O[sub 8]:Eu[sup 2+] by Partial Sr[sup 2+] Substitution for Ca[sup 2+]

Mechanoluminescence (ML) in a phosphor was greatly enhanced by partial substitution for ; ML intensity reached a maximum at content of 40 mol %. Moreover, ML was not observed at content of 80 mol % or higher. To investigate the relationship between ML and the crystal structure, Rietveld refinement of the crystal structures was performed, the results of which suggest that the observed ML enhancement and quenching phenomenon were associated with changes in the crystal lattice and crystal symmetry. Furthermore, the effects of partial substitution on the structure and photoluminescence characteristics were also investigated, and the emission peak was blueshifted from 428 to 403 nm due to the decrease in the crystal field intensity around . Based on electroluminescence measurements and the structural properties of the material, a possible mechanism for the enhancement in ML intensity is proposed.