Self-recovery of mechanoluminescence in ZnS:Cu and ZnS:Mn phosphors by trapping of drifting charge carriers

The long time dream of mechanoluminescence (ML) research to fabricate mechanoluminescence white light sources and mechanoluminescence displays seems to be turning into reality after the recent demonstration of highly bright and durable mechanoluminescent flexible composite films with a brightness of ≈120 cd/m2 and durability over ≈100 000 repeated mechanical stresses by using a combination of copper-doped zinc sulfide (ZnS:Cu) particles and polydimethylsiloxane. The present paper explores that self-recovery of mechanoluminescence of deforming piezoelectric semiconductors takes place by trapping of drifting charge carriers in the presence of piezoelectric field. This may be useful in enhancing the intensity and durability of ML devices.