3D Conformal Fabrication of Piezoceramic Films

Abstract

Piezoceramic films are an essential class of energy-conversion materials that have been widely used in the electronics industry. Although current methods create a great freedom for fabricating high-quality piezoceramic films, it requires well-controlled synthesis conditions, including special high-cost equipment and planar substrates particularly. The limited substrate selections hinder the applications of piezoceramic films in 3D conformal structures where most objects possess complex curvilinear surfaces. To overcome such limitations, a fast, energy-efficient, and cost-effective approach, named flame treated spray (FTS) coating, is developed for preparing piezoceramic films on free-form surfaces. The flame treatment significantly enhances the hydrophilicity of a substrate, assisting in forming a uniform and continuous thin film. The followed spray coating deposits hundreds of nanometers to several micrometers thick films on 3D free-form surfaces. Given the size controllability and arbitrary surface compatibility of the FTS method, a highly conformal piezoelectric tactile sensor array (4 × 4) is assembled on a spherical surface for mimicking robot fingers and an on-site thin-film sensor on the wing of an aircraft model to monitor the vibration in real-time during flight. The FTS film deposition offers a highly promising methodology for the application of functional thin-film from micro-to marcoscale devices, regardless of conformal problems.

Flexible inorganic piezoelectric functional films and their applications

“…The above-mentioned processing methods are widely used to prepare the inorganic piezoelectric films, especially that the sol-gel and hydrothermal methods have now matured. Besides, there are many other techniques that have been employed for different purposes, such as sputtering [130,131], metal-organic chemical vapor deposition (MOCVD) [132], mechanical thinning [133], and flame treated spray (FTS) coating methods [42].…”

“…These devices can not only store energy from various human activities for power supply as energy harvesters, but also serve as sensors or actuators for motion sensing, human-machine interaction, and clinical diagnosis [34,[37][38][39][40][41]. In addition, they can also respond to environmental mechanical vibrations or external stimuli, broadening the application of flexible piezoelectric devices in other fields [8,42]. In recent years, there have been many reviews summarizing the related progress of flexible polymer-based piezoelectric materials and composites, e.g., poly(vinylidene fluoride) (PVDF) [26,[43][44][45].…”

Bio-inspired water-driven electricity generators: From fundamental mechanisms to practical applications

“…To harvest the gigantic water energy, conventional techniques mainly have received great success in harvesting intensive water energy such as sea wave energy and river potential energy by the use of the heavy and bulk electromagnetic generators, however, fail to harvest the decentralized and small-scale water energy stored in the various forms of water motion, such as raindrops, river flows, ocean waves, and others (Figure 1). To this end, a myriad of water-driven electricity generators with various mechanisms such as piezoelectric nanogenerators [4,5], hydrovoltaic technology [6,7], thermoelectricity [8], and triboelectric nanogenerator (TENG) have been proposed [9][10][11][12][13]. Despite the extensive progress, working in a wide range of working conditions [14][15][16][17][18][19], the existing water energy harvesting techniques are still susceptible to various issues, such as low energy conversion, poor durability, poor scalability and low integration, resulting from oversimplified artificial designs [20][21][22][23][24][25][26][27].…”

Bioinspired Dual‐Mode Stretchable Strain Sensor Based on Magnetic Nanocomposites for Strain/Magnetic Discrimination

“…As wearable electronic devices are rapidly developing, the preparation of flexible sensors has opened up broad prospects, such as electronic skin, [1][2][3][4][5][6] health monitoring, [7][8][9][10][11][12][13][14][15][16] and intelligent robots. [17][18][19][20][21][22][23][24] Flexible sensors detect various external stimuli, including strain, pressure, and magnetic field, by monitoring the response signal. [25,26] The flexible sensors reported by researchers mainly include strain sensors, magnetic field sensors, and pressure sensors, which can usually detect individual external stimulus information, and cannot meet the gradually increasing demand for multimodal sensing or responses.…”