Ultrathin Ceramic Piezoelectric Films via Room-Temperature Electrospray Deposition of ZnO Nanoparticles for Printed GHz Devices

Abstract

High-frequency devices are key enablers of state-of-the-art electronics used in a wide and diverse range of exciting applications such as inertial navigation, communications, power conversion, medicine, and parallel computing. However, high-frequency additively manufactured piezoelectric devices are yet to be demonstrated due to shortcomings in the properties of the printed transducing material and the attainable film thickness. In this study, we report the first room-temperature-printed, piezoelectric, ultrathin (<100 nm) ceramic films compatible with high-frequency (>1 GHz) operation. The films are made of zinc oxide (ZnO) nanoparticles via near-field electrohydrodynamic jetting, achieving film piezoelectricity, without high-temperature processing, through a novel mechanism that is controlled during the deposition. Optimization of the printing process and feedstock formulation results in homogeneous traces as narrow as 213 μm and as thin as 53 nm as well as uniform field films as thin as 91 nm; the printing technique can be used with flexible and rigid, conductive and insulating substrates. The crystallographic orientation of the imprints toward the (100) plane increases if the rastering speed during printing is augmented, resulting in a larger piezoelectric response. The resonant frequency of film bulk acoustic resonators increases monotonically with the rastering speed, achieving transmission values as high as 4.99 GHz, which corresponds to an acoustic velocity of 2094 m/s, similar to the expected transverse value in high-temperature-grown ZnO films. Piezoresponse force microscopy maps of printed field films show local variation in the piezoelectric behavior across the film, with an average piezoelectric response as high as 21.5 pm/V, significantly higher than the d 33 piezoelectric coefficient of single-crystal, high-temperature-grown ZnO, and comparable with reported values from ZnO nanostructures.

3D Printable Hydrogel Bioelectronic Interfaces for Healthcare Monitoring and Disease Diagnosis: Materials, Design Strategies, and Applications

“…In another study, Pal et al fabricated a 3D printable zirconia (Zr)-based metal-organic framework (MOF) ionogel for wearable sensor and colorimetric biosensing applications. [324] The printable ionogel comprised Surface sensor [298] Custom-made printing (ultrasound pressure) Helical surface sensor [299] 3D stereo lithography (UV assessed) Array sensor body [300] FDM printing Sensing layer [301] Inkjet printing Sensing layer [247] Piezoresistive sensing FDM printing Sensing layer, Sensor body [302] Aerosol jet printing (200 μm) Sensing layer [303] DIW printing (10 μm)…”

Recent Advances in Self-powered Sensors Based on Nanogenerators: From Material and Structural Design to Cutting-Edge Sensing Applications

“…However, in the field of flexible self-powered sensors, it is difficult to use piezoelectric ceramics in wearable sensing due to their rigidity and brittleness. Therefore, to cater to the demand for flexible self-powered sensors, piezoelectric ceramics have been modified into nanoscale piezoelectric films and nanostructures, such as nanofibers, nanoparticles, and nanotubes, in order to enhance their flexibility and stretchability. − Noh et al designed a laser-exfoliated self-powered flexible touch sensor based on the PZT film as shown in Figure A . Flexible touch sensors based on piezoelectric ceramics offer unique benefits including scalable fabrication, fast response times, durability and self-powering capability.…”

Electro‐Optic Metasurfaces Based on Barium Titanate Nanoparticle Films

“…As a result, we expect an improvement on the electro‐optic response if special treatment like capillary assembly of nanoparticles or crystallographic alignment of nanoparticles during self‐assembly is achieved. [ 35,36 ] However, the electro‐optic response detected is already comparable to bulk electro‐optic LiNbO 3 crystals, while further optimized design of metasurface can translate the electro‐optic response of BaTiO 3 nanoparticle film in even higher modulation depths. The electro‐optic effect of BaTiO 3 nanoparticles relies on the tetragonal phase of the crystal.…”