Intense NIR mechanoluminescence from Al3+-regulated MgGa2O4: Cr3+

Mechanoluminescent (ML) materials, with the advantages of stress visualization and real-time dynamic response, has great application prospects in stress sensing, display, and non-destructive stress detection. In this work, the Cr3+-doped MgGa2O4 phosphor was proposed and investigated systematically. It emits near-infrared ML by compounding without pre-irradiation, and the intensity of ML can be significantly enhanced through UV irradiation. In addition, the crystal field of Cr3+ ions was tuned through the introduction of Al3+ ions. More importantly, the introduction of Al3+ ions changed the trap distribution of the materials, which greatly enhanced the strength of ML. Finally, based on the small interference of NIR by visible light and excellent penetration, the ML signal was successfully monitored in a bright environment by combining with polydimethylsiloxane (PDMS), and it could penetrate about 5 mm of skin tissue, which exhibits certain applications prospects for stress monitoring in a bright environment and stress monitoring in the human body.