Stretchable Piezoelectric Sensing Systems for Self‐Powered and Wireless Health Monitoring

Abstract

Wearable electronics are attracting increasing attention as recent developments in materials, mechanics, and manufacturing techniques create new opportunities for the integration of high-quality electronic systems into a single miniaturized Continuous monitoring of human physiological signals is critical to managing personal healthcare by early detection of health disorders. Wearable and implantable devices are attracting growing attention as they show great potential for real-time recording of physiological conditions and body motions. Conventional piezoelectric sensors have the advantage of potentially being self-powered, but have limitations due to their intrinsic lack of stretchability. Herein, a kirigami approach to realize a novel stretchable strain sensor is introduced through a network of cut patterns in a piezoelectric thin film, exploiting the anisotropic and local bending that the patterns induce. The resulting pattern simultaneously enhances the electrical performance of the film and its stretchability while retaining the mechanical integrity of the underlying materials. The power output is enhanced from the mechanoelectric piezoelectric sensing effect by introducing an intersegment, through-plane, electrode pattern. By additionally integrating wireless electronics, this sensing network could work in an entirely battery-free mode. The kirigami stretchable piezoelectric sensor is demonstrated in cardiac monitoring and wearable body tracking applications. The integrated soft, stretchable, and biocompatible sensor demonstrates excellent in vitro and ex vivo performances and provides insights for the potential use in myriad biomedical and wearable health monitoring applications.

The Evolution of Flexible Electronics: From Nature, Beyond Nature, and To Nature

“…[262] The pursuit of self-powered electronics based on energy harvesting technologies by extracting energy from the ambient environment and converting to electricity are rather intriguing for the development of compact, flexible, and wearable devices without the utilization of heavy batteries. [263][264][265][266][267][268] This section will review on the self-powered sensors with various sensing functionality, [269] such as light detecting, [270] gas sensing, [271,272] motion sensing, [273,274] physiological signals sensing, [275] etc., which were based on the energy-harvesting technologies including photovoltaic, [276,277] thermoelectric, [278,279] piezoelectric, [280,281] and triboelectric effect, [282][283][284] etc. The selfpowered ability is considered "beyond nature" as the integration Figure 15.…”

Soft Electronics for the Skin: From Health Monitors to Human–Machine Interfaces

“…[34] In addition to imparting flexibility to electronic devices, they also require mechanical stretchability to better interface and concurrently deform with the skin. Two strategies have been applied to achieve mechanical stretchability in soft electronics: 1) utilizing intrinsically stretchable, rubbery materials including rubbery electronic materials (semiconductors, conductors, and dielectrics) [14,15,24,[35][36][37][38][39][40][41][42][43][44][45] and liquid metals [46][47][48][49] to build the electronics; 2) employing engineered structures like wrinkles, [34,[50][51][52][53][54][55][56] serpentines, [12,17,33,44,[57][58][59][60][61] island-bridge structures, [62,63] textiles, [64] origami, [65,66] kirigami, [37,67] and microcracks [68] to accommodate the induced strain. [30,…”

Advances in Materials for Soft Stretchable Conductors and Their Behavior under Mechanical Deformation

“…They are particularly promising as energy harvesters to leverage energy from various mechanical deformations like body movement [ 170 , 171 , 172 , 178 , 179 ]. Most piezoelectric materials are rigid, inorganic, and require complicated microfabrication techniques to process into thin films for greater flexibility [ 180 , 181 ]. Common piezoelectric materials for wearable sensors are lead zirconate titanate (PZT), zinc oxide (ZnO) nanowires, and polyvinylidene fluoride (PVDF).…”