Blue light emission from stress-activated CaYAl3O7 : Eu

We have revealed that CaYAl3O7: Eu 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 1300 degrees C 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 Eu2+ ions as PL. This blue ML emission can be observed by the naked eye when the sample sintered at 1300 degrees C is compressed. Furthermore, the ML intensity of CaYAl3O7: Eu proportionally increased with the increase of mechanical load. (C) 2008 The Electrochemical Society.