3D Printing of Auxetic Self-powered Mechanoluminescent Photonic Skins for Underwater Communication and Safety Monitoring.

Stretchable mechanoluminescent (ML) photonic skin with strong and stable brightness holds great promise for underwater communication and safety monitoring. However, traditional film-based ML devices often lack the compliance needed to accommodate curved surfaces and face a trade-off between extensibility and luminescent intensity. This study introduces a 3D-printed self-powered auxetic ML photonic skin. By utilizing auxetic materials with a negative Poisson's ratio, we created a stretchable ML device that conforms to complex, curved surfaces, enhancing its applicability in dynamic underwater settings. By encapsulating the auxetic ML structure in silicone, simultaneous improvements in brightness uniformity and stretchability are achieved. The device exhibits remarkable durability, maintaining consistent light emission and mechanical performance over 10 000 cycles, and demonstrates the potential for real-time underwater communication and safety monitoring. Integrated into a glove, a swimming toy, and a gas tank, the photonic skin successfully transmitted Morse code signals and detected gas leaks, showcasing its versatility and robustness in harsh underwater conditions. These findings underscore the potential of this technology to improve safety and efficiency in marine exploration, paving the way for further advancements in underwater robotics and communication.