Triboluminescence dominated by crystallographic orientation

Triboluminescence (TL) is an optical phenomenon that has a long and varied history with broad applications, such as damage detection, X-ray source, and mass health monitoring sensor. So far, the properties and mechanisms of TL remain not completely understood. The TL properties emitted during the sliding contact between Al(2)O(3) and SiO(2) surfaces were studied along different crystallographic orientations. In this study, the TL intensity of Al(2)O(3) was significantly enhanced as Al(2)O(3) surface was along a particular crystallographic orientation, which is an unconventional phenomenon. TL enhancement of Al(2)O(3) was not affected by air atmosphere and atomic stocking mode of Al(2)O(3). The enhancement mechanism of Al(2)O(3) may be influenced by the surface state of Al(2)O(3). This work provides a new method to control the intensity of TL and novel ideas to elucidate the TL mechanism.