Mechano-luminescence of Eu²⁺, Dy³⁺ co-doped strontium aluminate phosphors with the substitution of calcium ions

Mechano-luminescent material can emit light under various external mechanical forces such as pressure, friction, impact and ultrasound. Elastic-luminescent materials have the property that the light signal increases linearly with the increase in stress and has been widely applied. A series of strontium aluminate/strontium calcium samples doped together with europium and dysprosium have been prepared by a high-temperature solid-state method. The effect of strontium/calcium ratio on the crystal structure and luminescence property of the samples have been systematically studied. With the increase of Ca substitution, the crystal field environment around divalent europium ions varies which leads to the changes of the emission peaks. The color presented from samples was tuned from green to blue which offers the possibility of color regulation of mechano-luminescence. Among these samples, the elastic-luminescence of the sample Sr0.8Ca0.2Al2O4: Eu2+, Dy3+ shows an excellent performance as the signal increases linearly with the applied pressure, so it has the potential to be used as a pressure sensor.