Blue Light Emission from Stress-Activated CaYAl[sub 3]O[sub 7]:Eu

We have revealed that phosphor emits blue light under the application of mechanical stress, called mechanoluminescence (ML). The influences of sintering temperature on photoluminescence (PL) and ML were investigated in order to gain suitable synthesis conditions. The results revealed that the sample sintered at shows strong PL and ML intensities, while further heating induces quenching of PL and ML. The ML and PL spectra are similar, which indicates that ML is emitted from the same center of ions as PL. This blue ML emission can be observed by the naked eye when the sample sintered at is compressed. Furthermore, the ML intensity of proportionally increased with the increase of mechanical load.