High-Density Flexible Piezoelectric Sensor Array With Double Working Modes

Abstract

Flexible and self-powered sensing device has aroused considerable interest in the field of the Internet of Things (IoT) and artificial intelligence (AI) in recent years. For more detailed and sensitive perception of the surroundings and external stimuli, sensors with high density and sensitivity are highly desirable. Here, this article reported a simple and low-cost strategy to realize a high-performance flexible piezoelectric sensor array composed of 30 sensing points with a high density of 11.11 cm <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$^{-{2}}$ </tex-math></inline-formula> . The piezoelectric sensor array was analyzed by a finite-element model and characterized through sound pressure measurement and wrist bending for motion monitoring under <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${d}_{{33}}$ </tex-math></inline-formula> and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${d}_{{31}}$ </tex-math></inline-formula> modes, respectively. The flexible sensor array with the total thickness of 125 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{m}$ </tex-math></inline-formula> exhibits a high sensitivity of 447.82 mV <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\cdot $ </tex-math></inline-formula> kPa <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$^{-{1}}$ </tex-math></inline-formula> with an ultralow detection limit of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\sim 3.60$ </tex-math></inline-formula> Pa. Our work provides a simple strategy for the application potential in smart wearable electronics and human–machine interaction (HMI) areas.