Flexible mechanical sensors with photoelectric dual-signal outputs based on bio-inspired mechanoresponsive photonic crystals

The rapid development of flexible electronics has provided significant impetus for the advancement of wearable mechanical sensors, demonstrating considerable potential in fields such as electronic skin, health monitoring, and human-machine interaction. However, most existing flexible mechanical sensors still rely on a single electrical signal output mechanism. Their inherent limitations, including insufficient visualization capability and poor environmental adaptability, present challenges for further application and development. Inspired by structural coloration phenomena in natural photonic crystals, flexible mechanical sensors that integrate both electrical signals and optical visual outputs have emerged as a novel and highly promising sensing platform. The performance enhancement of these sensors stems from the synergistic design of functional materials, wherein multiscale chemical interactions, which include both the internal molecular forces within each component and the interfacial bonding between them, play a crucial role in achieving stable and synergistic photoelectric responses. This review systematically summarizes recent research progress in bio-inspired mechanoresponsive photonic crystal-based flexible mechanical sensors with dual photoelectric signal outputs. Following a respective overview of flexible mechanical sensing units and mechanoresponsive photonic crystal materials, it focuses on analyzing their synergistic photoelectric regulation mechanisms and sensing performance. Finally, the review provides an in-depth discussion of current key challenges and future research directions in this field. • Performance optimizations of flexible mechanical sensors are summarized. • Strategies on the regulation of the structure for bio-inspired mechanoresponsive photonic crystals are presented. • The mechanism of coordination interactions in achieving signal concordance of photoelectric sensors is discussed. • The key role of coordination chemistry toward multifunctional performance in dual photoelectric signal sensors is proposed.