Modeling and Simulation of PVDF-TrFE Based MEMS Scale Cantilever Type Energy Harvesters

A. Toprak, O. Tigli
University of Miami, US

Keywords: energy harvesting, PVDF-TrFE, piezoelectric

Summary:

We present the FEM modeling and simulation of a cantilever type piezoelectric energy harvester constructed using PVDF-TrFE. PVDF-TrFE is a CMOS compatible, soft piezoelectric polymer with a moderate electromechanical coupling coefficient. It is also flexible and biocompatible, which makes it especially attractive for IMDs. Simplicity of its process allows creating multiple PVDF-TrFE/electrode layers. To the best of our knowledge, energy harvesting performance of PVDF-TrFE based cantilevers is not studied to date. Modeled cantilever beam consists of a 7.25 µm PVDF-TrFE piezoelectric layer on top of a 2 µm-thick SiO2 film. Output power and voltages are simulated in frequency domain with a tip load of 10 µN. For comparison, same analysis is repeated using ZnO, AlN, and PZT-5A while varying the thicknesses and operating frequency to keep the neutral axis and tip displacement constant. Simulated maximum output powers and corresponding voltages for PVDF-TrFE, ZnO, AlN, and PZT-5A are 60.3 nW at 0.73 V, 62.0 nW at 0.32 V, 12.4 nW at 0.13 V, and 301.9 nW at 0.07 V, respectively. The effects of a multi-layer approach on the device outputs are also simulated for PVDF-TrFE, and the results show that the output power is not affected by the number of layers.