Turning sound and force into light with AlN:Mn²⁺ mechanoluminescence

The development of multifunctional photo- and mechanoluminescent materials capable of responding to diverse external stimuli, enabling the visualization of mechanical action and acoustic waves, is essential for next-generation sensing and optoelectronic technologies. In this study, we present Mn²⁺-doped aluminum nitride (AlN:Mn²⁺) as a luminescent material that simultaneously exhibits bright orange photoluminescence, strong and long-lasting persistent luminescence, thermoluminescence, and mechanoluminescence (ML). AlN:Mn²⁺ demonstrates multimodal ML behavior under various mechanical stimuli, including friction, impact, and ultrasonic excitation, highlighting its potential for force and sound sensing applications across a wide range of environments. This is crucial for next-generation energy transformation, enabling the conversion of heat, force, and sound into light. The integration of persistent, thermal, mechanical, and acoustic luminescence within a single, robust, and chemically stable material makes AlN:Mn²⁺ a promising candidate for remote, adaptive optomechanical, and photoacoustic applications in biomedical diagnostics, structural health monitoring, anticounterfeiting, remote sensing, and innovative electronics.