Flexible Fibrous Piezo-Electric Sensor on Printed Silver Electrode

PDF / 48,387,553 Bytes
5 Pages / 612 x 792 pts (letter) Page_size
53 Downloads / 237 Views

Flexible Fibrous Piezo-Electric Sensor on Printed Silver Electrode Ho Yeon Son1,2, Yoon Sung Nam2,3 and Woo Soo Kim1 1 School of Mechatronic Systems Engineering, Simon Fraser University, Surrey, B.C. Canada V3T 0A3 2 Department of Materials Science and Engineering, and 3KAIST Institute for NanoCentury and BioCentury, Korea Advanced Institute of Science and Technology, Daejeon, Republic of Korea 305-701 ABSTRACT Here we introduce a facile method to fabricate a flexible piezoelectric sensor using onedimensional (1-D) piezoelectric poly(vinylidene fluoride) (PVDF) nanofibers directly produced onto flexible printed electrodes by electro-spinning without an additional poling process. The flexible silver electrodes are fabricated on polyethylene terephthalate (PET) using silver nanowires by easy and cost-effective spraying deposition. The electrospun PVDF nanofibers have uniaxially aligned arrays on the electrodes by using a rotating collector. The fabricated PVDF piezoelectric sensors demonstrate the piezoelectric responses with repeated mechanical stimuli with good flexibility and high sensitivity. We expect that the facile fabrication of PVDF piezoelectric sensors on flexible printed electrodes can be usefully exploited to integrate the piezoelectric sensors into flexible and stretchable functional electronic devices. INTRODUCTION Recently there has been increasing attention on poly(vinylidene fluoride) (PVDF) as a piezoelectric material for the fabrication of highly sensitive piezoelectric sensors and nanogenerators because of its good piezoelectric and mechanical properties, easy processing and flexibility [1,2]. Flexible piezoelectric sensors fabricated on bendable and stretchable electrodes with good piezoelectric responses are still challenging tasks for a wide range of applications for flexible and stretchable energy harvesting and/or sensing devices. Recently, electro-spinning technique is widely used for the fabrication of one-dimensional (1-D) piezoelectric PVDF nanofibers without additional poling processes [3,4]. In particular, the PVDF nanofibers collected by a rotating collector show uniaxial alignments and improved piezoelectric responses by an enhanced fraction of a polar β-phase [5,6]. In this study, flexible silver electrodes were prepared using silver nanowires (Ag NWs) by spraying deposition, which are process-effective and cost-effective for the fabrication of flexible electrodes [7]. Piezoelectric PVDF nanofibers were produced directly onto the electrode by electro-spinning to fabricate the piezoelectric sensors without any additional poling processes. The output voltage and current were repeatedly generated when bending and releasing forces were applied to the piezoelectric sensors. EXPERIMENTAL DETAILS

Ag NWs were synthesized as previously reported [8]. The printed electrodes of Ag NWs were prepared on flexible polyethylene terephthalate (PET) films by spray-deposition using an air-brush of a spray gun (Iwata 4292 HI-LINE KUSTOM) [7]. After the deposition of Ag NWs, the silver electrodes were h