A Flexible Film Bulk Acoustic Resonator Based on -Phase Polyvinylidene Fluoride Polymer.

Ting Wu,Xiang Tao,Shurong Dong,Shuting Liu,Leihe Lu,Shuyi Huang,Lin Shi,Jikui Luo,Hongsheng Xu,Hao Jin,Weipeng Xuan,Zijing Fang

doi:10.3390/s20051346

Abstract

This paper reports a novel flexible film bulk acoustic resonator (FBAR) based on -phase polyvinylidene fluoride (PVDF) piezoelectric polymer. The proposed device was simulated and evaluated; then, a low-temperature photolithography process with a double exposure method was developed to pattern the electrodes for the device, which enabled the device to retain the piezoelectric properties of the -phase PVDF film. Results showed that the β-phase PVDF FBARs had a resonant frequency round 9.212 with a high electromechanical coupling coefficient () of 12.76% ± 0.56%. The device performed well over a wide bending-strain range up to 2400 owing to its excellent flexibility. It showed good stability as a strain sensor with a sensitivity of 80 , and no visible deterioration was observed after cyclic bending tests. The PVDF FBAR also exhibited an exceptionally large temperature coefficient of frequency (TCF) of −4630 , two orders of magnitude larger than those of other FBARs based on common inorganic piezoelectric materials, extraordinarily high sensitivity for temperature sensing. All results showed that -phase PVDF FBARs have the potential to expand the application scope for future flexible electronics.

Highlights

Flexible electronic technologies are very attractive for their use in many novel applications such as wearable electronics, implantable medical devices, and healthcare systems [1]
Kawai in 1969 [9], Polyvinylidine difluoride (PVDF)-based piezoelectric polymer has been used in a wide range of actuators and
We report on the feasibility of using a β-phase PVDF polymer for the development

Summary

Introduction

Flexible electronic technologies are very attractive for their use in many novel applications such as wearable electronics, implantable medical devices, and healthcare systems [1]. Kawai in 1969 [9], PVDF-based piezoelectric polymer has been used in a wide range of actuators and [11], acceleration sensors [12], surface acoustic-wave devices [13], pressure sensors [14], and energy sensors, such as underwater acoustic transducers [10], ultrasonic inspection sensors [11], acceleration harvesters [15] It has been utilized in medical and biological applications such as sensors [12], surface acoustic-wave devices [13], pressure sensors [14], and energy harvesters [15]. It has been utilized in medical and biological applications such as artificial muscles and PVDF polymer cannot be processed by a standard lithography process, limiting its application in organs [16], medical imaging [17], and blood-flow monitors [18].

Numerical

Device

Strain Response

Temperature Sensing

Conclusions