Wafer-scale heterostructured piezoelectric bio-organic thin films

Abstract

Piezoelectric biomaterials are intrinsically suitable for coupling mechanical and electrical energy in biological systems to achieve in vivo real-time sensing, actuation, and electricity generation. However, the inability to synthesize and align the piezoelectric phase at a large scale remains a roadblock toward practical applications. We present a wafer-scale approach to creating piezoelectric biomaterial thin films based on γ-glycine crystals. The thin film has a sandwich structure, where a crystalline glycine layer self-assembles and automatically aligns between two polyvinyl alcohol (PVA) thin films. The heterostructured glycine-PVA films exhibit piezoelectric coefficients of 5.3 picocoulombs per newton or 157.5 × 10−3 volt meters per newton and nearly an order of magnitude enhancement of the mechanical flexibility compared with pure glycine crystals. With its natural compatibility and degradability in physiological environments, glycine-PVA films may enable the development of transient implantable electromechanical devices.

More Powerful Twistron Carbon Nanotube Yarn Mechanical Energy Harvesters

“…Improved means for converting mechanical energy to electricity are needed for diverse applications, from harvesting ocean wave energy to power cities to using body motion to power sensors and energystorage devices in and on the human body. [1][2][3][4][5][6] Recently described coiled carbon nanotube (CNT) yarns, called twistrons, [7] use stretch-induced changes in electrochemical capacitance to generate higher peak electrical power per harvester weight than generated by any prior-art mechanical energy harvester for mechanical frequencies between 6 and 600 Hz.…”

Optimizing Piezoelectric Nanocomposites by High‐Throughput Phase‐Field Simulation and Machine Learning

“…High‐throughput phase‐field simulations are performed to analyze the effective properties of the BTO/PVA composites with versatile geometrical morphologies to design the optimal configuration with both excellent piezoelectric and mechanical properties. In this study, we choose PVA as the polymer matrix because PVA has good degradability, [ 42 ] stretchability, [ 43 ] biologically compatibility, [ 44 ] and self‐healing ability, [ 45 ] which makes it an excellent candidate material for biomedical applications. For the high‐throughput calculations, a set of 400 (20 × 20) composite architectures are generated simultaneously to form a computing dataset by tuning the geometric ratios a y / a z and a x /a z of oxide fillers ranging from 0.1–10, assuming that the oxide fillers randomly disperse in the polymer matrix with a constant volume fraction of 1 vol%.…”

An Insight into Tunable Innate Piezoelectricity of Silk for Green Bioelectronics

“…A recent study by Yang et al reported a self-assembly method to develop highly crystalline and selfaligned γ-glycine piezoelectric films. [49] PVA-glycine-PVA sandwich heterostructure assisted oriented growth of piezoelectric γ-glycine by forming strong hydrogen bonds between O-atoms in glycine and À OH on PVA chains. The films exhibited a piezoelectric response comparable to the other commercially available piezoelectric materials such as PVDF.…”