Multifunctional sub-100 µm thickness flexible piezo/triboelectric hybrid water energy harvester based on biocompatible AlN and soft parylene C-PDMS-Ecoflex™

A Thickness-Mode High-Frequency Underwater Acoustic Transducer with a Low Sidelobe Level

“…J 0 (k r a) and J 1 (k r a) are the zero order and first order of the Bessel function of the first kind. The coupling coefficient n is solved from Equation (1), and then the higher order frequency of radial and thick vibration can be obtained by substituting Equations ( 2) and (3). From the calculation formula, considering the coupling, the radial vibration frequency is not only related to the material parameters, diameter size, but also the ratio of thickness to diameter, and the thickness vibration frequency is the same.…”

“…Therefore, the material type, size and structure shape should be further considered. According to reference [3], it is deduced that , n is called the coupling coefficient between the radial and thickness of the disk oscillator. The equations of coupling coefficient, radial vibration frequency and thickness vibration frequency are:…”

“…Taking a PZT-4 piezoelectric ceramic disc with diameter 2a = 60 mm and thickness 2t = 10 mm as an example, the resonant modes of radial vibration and thickness vibration are calculated by ( 2) and ( 3). The theoretical calculation and finite element calculation re- Taking a PZT-4 piezoelectric ceramic disc with diameter 2a = 60 mm and thickness 2t = 10 mm as an example, the resonant modes of radial vibration and thickness vibration are calculated by (2) and (3). The theoretical calculation and finite element calculation results of piezoelectric vibrator of the same size and material are as follows.…”

“…Piezoelectric transducers with piezoelectric ceramic as the functional material have higher reliability, impact resistance and long-time working stability than flexible sensors. It is the mainstream device of underwater acoustic systems [2][3][4][5]. The thickness vibration mode is the dominant working mode for high-frequency transducers.…”

Conformal, Ultra‐thin Skin‐Contact‐Actuated Hybrid Piezo/Triboelectric Wearable Sensor Based on AlN and Parylene‐Encapsulated Elastomeric Blend

“…Among several categories of FWE for human skin sensing, piezoelectric and triboelectric technologies can convert even tiny mechanical deformations into electrical energy at the micro‐ and nanoscale. [ 16 ] They can be very soft, cost‐effective, and easy to fabricate, [ 17–20 ] conformal and biocompatible, [ 4,21,22 ] owing to the discovery and employment of new materials [ 17,23,24 ] and architectures. [ 25,26 ] Several other biocompatible wearable sensors and biomimetic skins have been proposed, based on strain gauges, [ 27 ] capacitive devices, [ 28 ] or iontronics.…”