Ultralarge Elastic Deformation (180° Fold) of Cubic-^natBP Microwires for Wearable Flexible Strain Sensors

Abstract

Flexible strain sensors that can convert mechanical irritation from an external environment into electrical signals are key components in wearable devices. Here, using the principle of a B–Ni phase diagram, a pure-phase cubic natural boron phosphide (c-natBP) single-crystal microwire is obtained, which possesses ultralarge elastic deformation realized with the bending degree up to 180°. Based on the natBP microwire, a flexible strain sensor is prepared with an obvious quasi-linear response to external strain exhibited, which can be attributed to the Schottky barrier height (SBH) formed at the metal–crystal contact changing with the strain. Such strain-induced change results from lattice deformation, reconstructing the electronic structure and electron affinity. Furthermore, the effective and fast response of this flexible strain sensor in the practical applications of bicycle speed detection as well as finger and wrist bending detection demonstrates the potential of c-natBP microwire flexible strain sensors in wearable electronics, man–machine systems, and soft robotics.

Water-Induced Crystal-to-Crystal Transformation: Switchable Mechanical and Luminescent Properties

“…1−4 For instance, soft crystals with elasticity or plasticity have wide potential applications in flexible optical waveguides and wearable devices. 5,6 Rigid crystals with high Young's modulus and hardness show great advantages in defect-free crystal processing for optoelectronic devices. 7 Generally, the mechanical properties of organic crystals are highly related to the molecular packing and intermolecular interactions, presenting a complex and difficult task to predict at the molecular level.…”

“…The investigation of the mechanical properties of organic luminescent crystals has become an emerging field in materials science. − For instance, soft crystals with elasticity or plasticity have wide potential applications in flexible optical waveguides and wearable devices. , Rigid crystals with high Young’s modulus and hardness show great advantages in defect-free crystal processing for optoelectronic devices . Generally, the mechanical properties of organic crystals are highly related to the molecular packing and intermolecular interactions, presenting a complex and difficult task to predict at the molecular level. , Although diverse soft and rigid crystals have been constructed and reported, few of them have successfully achieved the regulation of mechanical properties via the molecular packing transition in a single system.…”