High-Efficiency Organic Mechanophosphorescence from A Phenoselenazine Phosphor for Multiple Applications

Mechanoluminescence (ML) materials with phosphorescent characteristics hold significant potential for applications in pressure sensing and material damage inspection. However, currently reported mechanophosphorescence (MP) materials suffer from low luminescence efficiency and insufficient brightness. Herein, we report a piezoelectric material, p-BPM, with an exceptionally high phosphorescence efficiency of 61.4%, which is the highest value among reported pure organic MP materials. Benefiting from its excellent ML performance, we have developed a display device using crystals that allow for clear observation of the written letter paths (letters M and L), which have promising prospects in pressure-sensitive display. Amazingly, we also observed that the crystals produce bright ultrasound induced luminescence in the medium at a low ultrasonic operating frequency (40 kHz). The composite films of crystal and poly(butylene adipate-co-terephthalate) (PBAT) polymer exhibit significant tensile strength while maintaining effective MP. The composite films show good piezoelectric energy harvesting properties with a maximum open-circuit voltage of 0.47 V and short-circuit current of 0.046 μA, demonstrating promise for precise sonic location. This work will facilitate the development of highly efficient organic MP materials, expanding the potential in stress-monitoring, imaging, and marine robotics.