Triboluminescence of Rare-Earth-Doped Celsian Polycrystals
Tomohiro Taniguchi, Koji Fujita, Tsuguo Ishihara, Katsuhisa Tanaka and Kazuyuki Hirao
Abstract:Triboluminescence has been observed in BaAl2Si2O8 and SrAl2Si2O8 doped with Eu2+@and Dy3+. Comparison between photoluminescence and triboluminescnece spectra, it is found that the emission intensity due to the 4f-4f transition of Dy3+ is larger in triboluminescence than in photoluminescence. It is thought that the crystal field is distorted around the rare earth ions which bring about the triboluminescence; the distorted crystal fields increase the transition propability of partly-forbidden 4f-4f transitions of Dy3+. On the other hand, the broad band due to the 4f-5d transition of Eu2+ shifts to longer wavelengths in the triboluminescence than in the photoluminescence. An increase in splitting of 5d levels and Stokes shift are possible origins for this phenomenon. Key Words:Triboluminescence, Rare earth, Hexacelsian