Models for intrinsic and extrinsic fracto-mechanoluminescence of solids

Mechanoluminescence of Dy doped strontium aluminate nanophosphors

“…It seems that in case ML the ratio between the intensities of second peak and first peak is much less and therefore second peak is not detected. Such difference in the PL and ML spectra for other crystals has also been reported [31]. It seems that the excitation by electron populates the states differently and therefore the population difference appears between the ML and PL spectra.…”

Optical Evaluation of In Situ Crack Propagation by Using Mechanoluminescence of SrAl2O4:Eu2+, Dy3+

“…With this regard, mechanoluminescence (ML), which is light emission resulting from any mechanical action, such as friction, tension, fraction, and compression, on a solid, has drawn significant attention as a stress sensor for its direct visualization and full‐field measurement of stress or crack through the ML light intensity. As a result, ML technologies have enabled the direct observation of the crack tip stress field, visualization of quasidynamic crack propagation, and bridging stress in a variety of ceramics by developing ML paints or pulsed laser deposition (PLD) coatings as an artificial skin to sense mechanical stress using visible light emission .…”

Sensing of shock-wave velocity and pressure using shock-wave induced mechanoluminescence of crystals

“…Furthermore, the electron-hole recombination may also cause the light emission. [22]. As no gas discharge is present in the ML spectra of lithium niobate crystals, it seems that the gas enters between the walls of cracks after the relaxation of surface charges of the crystal.…”

“…(ii) An intense electric field on the order of 10 8 Vm -1 is produced during the fracture of crystals [21][22][23][24].…”