Ternary-Host and Heterojunction Enabled Eye-Visible Elastic Mechanoluminescence from (Ca0.5Sr0.5)ZnOS/xZnS/Mn2+

Mechanoluminescence (ML) is one kind of mechanical-to-optical energy conversion, and a strategy toward achieving bright elastic ML emission is strongly anticipated for ML application. Herein, a ternary-host strategy is proposed for synthesizing heterojunction ML materials with eye-visible elastic ML under an ultralow pressure of 2 N, in which ZnS, CaCO3, and SrCO3 are employed as precursors to prepare the ternary-host (Ca0.5Sr0.5)ZnOS/xZnS. Upon partially substituting the precursor ZnS with MnCO3, the Mn2+ activator could introduce luminescent centers and carrier traps into the ternary-host (Ca0.5Sr0.5)ZnOS/xZnS and enable achieving a series of (Ca0.5Sr0.5)ZnOS/xZnS/Mn2+ phosphors with bright and pressure-sensitive elastic ML. The (Ca0.5Sr0.5)ZnOS/xZnS/Mn2+ phosphors not only exhibit eye-visible red ML under ambient conditions without any preirradiation but can also display a linearly enhanced ML intensity along with the enlarged external force at a 2 N interval as well as regeneratable ML upon repetitively applying an external force 20 times. The maximum emission wavelength of ML can be conveniently modulated from 623 to 658 nm by adjusting the ZnS content of (Ca0.5Sr0.5)ZnOS/xZnS/Mn2+ phosphors.