Tuning Mechanoluminescence From Red to Near-Infrared Light in CaZnOS:Mn2+

Mechanoluminescence (ML) materials can convert mechanical energy into photoelectrons and have significant potential for applications in intelligent sensing, self-driven luminescent displays, and human-computer interaction. Among the numerous ML systems, Mn²⁺-doped wurtzite-based phosphors have become a prominent ML family. However, their ML emissions are typically confined to visible light, which substantially limits their utility in fields such as biomechanics and bioimaging. Here, it is demonstrated that the photoluminescence (PL) and ML emission of CaZnOS:Mn²⁺ can be tuned from the red to near-infrared light (peaked at 770 nm) by regulating the Mn²⁺ ion concentration. The electronic paramagnetic resonance, PL lifetime, and various spectra reveal that the near-infrared emission originates from the enhanced magnetic interaction of Mn²⁺ pairs due to intrinsic defects. The heavy Mn²⁺-doped CaZnOS elastomer with near-infrared ML emission exhibits distinct advantages over low Mn²⁺-doped CaZnOS with only red emission in the field of biomechanical imaging. This work achieves near-infrared emission in CaZnOS phosphors singly doped with Mn²⁺ ions for the first time, providing a perspective for spectra broadening of Mn²⁺ ions-doped phosphors.