Innovation Strategy Selection Facilitates High-Performance Flexible Piezoelectric Sensors

Abstract

Piezoelectric sensors with high performance and low-to-zero power consumption meet the growing demand in the flexible microelectronic system with small size and low power consumption, which are promising in robotics and prosthetics, wearable devices and electronic skin. In this review, the development process, application scenarios and typical cases are discussed. In addition, several strategies to improve the performance of piezoelectric sensors are summed up: (1) material innovation: from piezoelectric semiconductor materials, inorganic piezoceramic materials, organic piezoelectric polymer, nanocomposite materials, to emerging and promising molecular ferroelectric materials. (2) designing microstructures on the surface of the piezoelectric materials to enlarge the contact area of piezoelectric materials under the applied force. (3) addition of dopants such as chemical elements and graphene in conventional piezoelectric materials. (4) developing piezoelectric transistors based on piezotronic effect. In addition, the principle, advantages, disadvantages and challenges of every strategy are discussed. Apart from that, the prospects and directions of piezoelectric sensors are predicted. In the future, the electronic sensors need to be embedded in the microelectronic systems to play the full part. Therefore, a strategy based on peripheral circuits to improve the performance of piezoelectric sensors is proposed in the final part of this review.

Microstructured capacitive sensor with broad detection range and long-term stability for human activity detection

“…With the increasing demand for artificial intelligence and the internet of things, the potential of flexible and wearable sensors in human-machine interaction, soft robots, and health monitoring applications have received great attention [1][2][3][4][5] . According to the sensing mechanism, the flexible sensors are divided into four types: resistive-type [6][7][8][9][10] , capacitive-type [11][12][13] , piezoelectrictype [14][15][16] , and triboelectric-type 5,17,18 . Among them, capacitive sensors have been intensively investigated owing to their characteristics of simple fabrication, good anti-interference, and excellent long-term stability [11][12][13]19 .…”

Conductive Porous MXene for Bionic, Wearable, and Precise Gesture Motion Sensors

“…is of value in studies of cognitive neuroscience, sports and military training, human-machine interfaces, and remote control [ 1 – 14 ]. To achieve real-time joint movement monitoring, precise and stable flexible hybrid electronic systems that integrate conformal physical sensors with miniaturized silicon-based rigid microcircuit chips can provide consumer-grade performance and reliability [ 15 – 28 ]. Thus, stable, precise conformal motion sensors with high sensitivity in a wide-angle range can not only reduce the computational cost but also improve system reliability and recognition rate.…”

Flexible ferroelectric wearable devices for medical applications

“…As a result, there is a substantial and growing interest in synthesizing flexible wearable devices using piezoelectric materials as they can both be used for sensing and energy harvesting. The sensing performance of piezoelectric materials is directly related to the piezoelectric strain coefficient d ij (charge per unit force) and g ij (electric field per unit stress) ( Duan et al., 2020 ). In addition, for energy harvesting applications, a low dielectric loss is favorable to maximize the efficiency of conversion from mechanical to electrical energy ( Roscow et al., 2015 ).…”