Emerging ultraviolet mechanoluminescent materials: mechanisms, design, and advanced applications

Mechanoluminescent (ML) materials directly convert mechanical energy into light, enabling applications in intelligent stress sensing and advanced light sources. Ultraviolet (UV) ML materials, particularly those operating in the solar-blind region (200-280 nm), offer significant advantages for high-signal-to-noise-ratio outdoor sensing owing to minimal interference from sunlight filtered by the Earth's ozone layer. Recent studies have demonstrated that rare-earth ions (Ce³⁺, Pr³⁺, Gd³⁺, Tm³⁺, Er³⁺, and Tb³⁺) and Bi³⁺ ions facilitate tunable ML emissions across the UVA to UVC spectral range. Advanced material design strategies such as trap-state modulation, piezo-/tribo-electric coupling, and molecular crystal engineering have been used to develop high-performance UV ML materials with enhanced ML intensity and tunable emission wavelengths. Despite these advances, a comprehensive systematic review focusing specifically on UV ML materials is lacking. This review addresses this critical gap by providing an in-depth analysis of the fundamental mechanisms, rational design principles, and performance optimization strategies for UV ML materials. Furthermore, this paper critically summarizes emerging applications in anti-counterfeiting, environmental sensing, structural monitoring, and UV disinfection. By identifying the current challenges and future research directions, this study aims to serve as a foundational reference for accelerating the development and practical implementation of next-generation UV ML materials.