Tuning the mechano-optical conversion in CaZnOS with Cu ion concentration

This article reports a new class of mechano-optical materials CaZnOS : Cu with a non-centrosymmetric layered structure. The mechano-optical conversion is strongly dependent on the Cu concentration in CaZnOS. The mechano-optical conversion of CaZnOS : Cu changes from initial mechanoluminescence to mechanical quenching (MQ) with increasing Cu concentration, and reaches a maximum MQ intensity at 0.01%. It is proposed that MQ arises from nonradiative recombination, caused by electron transfer from trap levels to nonradiative centers as a result of the mechanical load.