Deposition, Characterization, and Modeling of Scandium-Doped Aluminum Nitride Thin Film for Piezoelectric Devices

In this work, we systematically studied the deposition, characterization, and crystal structure modeling of ScAlN thin film. Measurements of the piezoelectric device’s relevant material properties, such as crystal structure, crystallographic orientation, and piezoelectric response, were performed to characterize the Sc0.29Al0.71N thin film grown using pulsed DC magnetron sputtering. Crystal structure modeling of the ScAlN thin film is proposed and validated, and the structure–property relations are discussed. The investigation results indicated that the sputtered thin film using seed layer technique had a good crystalline quality and a clear grain boundary. In addition, the effective piezoelectric coefficient d33 was up to 12.6 pC/N, and there was no wurtzite-to-rocksalt phase transition under high pressure. These good features demonstrated that the sputtered ScAlN is promising for application in high-coupling piezoelectric devices with high-pressure stability.

Research on a cascade model synthesis with the use of classical and non-classical methods in the context of new piezoelectric stack applications

Active audio noise cancellation technology using piezoelements is fairly new and emerging technology on the market in recent years and is still gaining in popularity. The ability to use piezoelectric devices to gather information about vibration spectrum and to create interfering waves, to cancel out the noise, allows for the reduction in passive vibration methods and gives more flexibility in terms of space and application. The idea of using this technique on larger scales such as industrial equipment is the focus of ongoing research conducted by the authors of this article. This work is intended as the first part of a larger project and focuses solely on theoretical approach to the problem of modelling mechatronic systems capable of creating complex vibration spectrums and using piezoelectric components. The authors have focused on creating a mix of classical and non-classical methods to synthesize model systems based on input resonance frequencies. A classical calculation through matrix equations was also done to validate the accuracy of obtained results through the structural number method. The resulting model is still awaiting the empirical verification through extensive testing on real-life models, and that part of the research is still being developed. When validated and checked, this technology could bring new solutions in the vibration damping of industrial equipment, potentially increasing its flexibility and effectiveness.

Rochelle Salt-Based Ferroelectric and Piezoelectric Composite Produced with Simple Additive Manufacturing Techniques

More than one century ago, piezoelectricity and ferroelectricity were discovered using Rochelle salt crystals. Today, modern societies are invited to switch to a resilient and circular economic model. In this context, this work proposes a method to manufacture piezoelectric devices made from agro-resources such as tartaric acid and polylactide, thereby significantly reducing the energy budget without requiring any sophisticated equipment. These piezoelectric devices are manufactured by liquid-phase epitaxy-grown Rochelle salt (RS) crystals in a 3D-printed poly(Lactic acid) (PLA) matrix, which is an artificial squared mesh which mimics anatomy of natural wood. This composite material can easily be produced in any fablab with renewable materials and at low processing temperatures, which reduces the total energy consumed. Manufactured biodegradable samples are fully recyclable and have good piezoelectric properties without any poling step. The measured piezoelectric coefficients of manufactured samples are higher than many piezoelectric polymers such as PVDF-TrFE.

Stretchable, Bio-Compatible, Antioxidant and Self-Powering Adhesives from Soluble Silk Fibroin and Vegetal Polyphenols Exfoliated Graphite

The development of bio-glues is still a challenging task, regarding adhesion on wet surfaces; often, high performance and adaption to complex geometries need to be combined in one material. Here, we report biocompatible adhesives obtained by blending regenerated silk (RS) with a soluble plant-derived polyphenol (i.e., chestnut tannin) that was also used to exfoliate graphite to obtain graphene-based RS/tannin (G-RS/T) composites. The resultant G-RS/T hybrid material exhibited outstanding stretchability (i.e., 400%) and high shear strength (i.e., 180 kPa), superior to that of commercial bio-glues, and showed sealant properties for tissue approximation. Moreover, we showed how such nanocomposites exhibit electromechanical properties that could potentially be used for the realization of green and eco-friendly piezoelectric devices. Finally, we demonstrate the in vitro glue’s biocompatibility and anti-oxidant properties that enable their utilization in clinical applications.

A Method for Quantitatively Separating the Piezoelectric Component from the as-received "Piezoelectric" Signal

Polymer-based piezoelectric devices are promising for developing future wearable force sensors, nanogenerators, and implantable electronics etc. The electric signals generated by them are often assumed as solely coming from piezoelectric effect. However, triboelectric signals originated from contact electrification between the piezoelectric devices and the contacted objects can produce non-negligible interfacial electron transfer, which is often combined with the piezoelectric signal to give a triboelectric-piezoelectric hybrid output, leading to an exaggerated measured “piezoelectric” signal. Herein, a simple and effective method is proposed for quantitatively identifying and extracting the piezoelectric charge from the hybrid signal. The triboelectric and piezoelectric parts in the hybrid signal generated by a poly(vinylidene fluoride)-based device are clearly differentiated, and their force and charge characteristics in the time domain are identified. This work presents an effective method to elucidate the true piezoelectric performance in practical measurement, which is crucial for evaluating piezoelectric materials fairly and correctly.

Structure and properties of K0.5Na0.5Nb0.96Sb0.04O3 piezoelectric ceramics doped by CuO

Envisaged through adding sintering additives to achieve low-temperature sintering preparation, in order to overcome the volatilization of sodium ions and potassium ions in the high-temperature preparation, so as to improve the density and electrical properties of KNN-based piezoelectric ceramics. This research uses traditional solid-state sintering technology, a high density, high properties lead-free piezoelectric ceramics, KNNSC-[Formula: see text], successfully prepared with sintering additives CuO. The modern test analysis of XRD and SEM shows that a moderate amount of CuO doped in the range of research can form a single perovskite structure of an orthorhombic structure, not found in any second phase, and can promote grain evenly growing and improve the sintering properties of KNN-based piezoelectric ceramics. The KNNSC-0.04 ceramics exhibit excellent electrical properties through various electrical tests such as [Formula: see text] = 238pC/N, [Formula: see text]= 47%, [Formula: see text]= 1049, tan[Formula: see text]= 2.4%, [Formula: see text] = 25.6 [Formula: see text]C/cm2, [Formula: see text] = 1.24 kV/mm, respectively. These test results show that the KNNSC-[Formula: see text] piezoelectric ceramics have great potential to be applied in middle- and low-voltage piezoelectric devices.

Boosting Performance of Self-Polarized Fully Printed Piezoelectric Nanogenerators via Modulated Strength of Hydrogen Bonding Interactions

Self-polarized piezoelectric devices have attracted significant interest owing to their fabrication processes with low energy consumption. Herein, novel poling-free piezoelectric nanogenerators (PENGs) based on self-polarized polyvinylidene difluoride (PVDF) induced by the incorporation of different surface-modified barium titanate nanoparticles (BTO NPs) were prepared via a fully printing process. To reveal the effect of intermolecular interactions between PVDF and NP surface groups, BTO NPs were modified with hydrophilic polydopamine (PDA) and hydrophobic 1H,1H,2H,2H-perfluorodecyltriethoxysilane (PFDTES) to yield PDA-BTO and PFD-BTO, respectively. This study demonstrates that the stronger hydrogen bonding interactions existed in PFD-BTO/PVDF composite film comparative to the PDA-BTO/PVDF composite film induced the higher β-phase formation (90%), which was evidenced by the XRD, FTIR and DSC results, as well as led to a better dispersion of NPs and improved mechanical properties of composite films. Consequently, PFD-BTO/PVDF-based PENGs without electric poling exhibited a significantly improved output voltage of 5.9 V and power density of 102 μW cm−3, which was 1.8 and 2.9 times higher than that of PDA-BTO/PVDF-based PENGs, respectively. This study provides a promising approach for advancing the search for high-performance, self-polarized PENGs in next-generation electric and electronic industries.