Search

Fluoropolymers and metal halide perovskites (MHPs), as two classes of important piezoelectric materials, suffer from active phases through a facile process and brittleness led poor manufacturability, respectively. Here, TMCM‐CdCl3/PVDF nanocomposites (TMCM = trimethylchloromethyl ammonium, PVDF = polyvinylidene fluoride) are synthesized to overcome the above shortcomings. The abundant hydrogen (H) and chlorine (Cl) sites in TMCM‐CdCl3 can interlock with H and fluorine (F) atoms within PVDF via C─H···Cl and C─H···F interactions. This programming effect augments the dipole alignment and consequently promotes the formation of polar phases within PVDF. The devices made by these nanocomposites exhibit high energy harvesting properties surpassing established MHP/PVDF analogues, and prominent performance in sensing delicate human motions. Moreover, the devices show exceptional capabilities for detecting underwater ultrasound waves. The signal intensity is ≈4 times that of commercial PVDF film devices, and the frequency distortion is only a quarter of that observed in commercial ceramic transducers. This study opens up new possibilities for developing high‐performance piezoelectric nanocomposites and the creation of advanced electromechanical devices. [ABSTRACT FROM AUTHOR]

Chiral hybrid metal halides have emerged as a promising class of piezoelectric materials owing to their ease of synthesis, low acoustic impedance, and solution processibility. However, many known chiral halides crystalize in structures with only shear piezoelectricity which is less facile to be utilized compared with the longitudinal piezoelectricity, largely preventing their practical utility. In addressing this problem, chiral lead‐free S‐MPBiCl5 and R‐MPBiCl5 (MP = 2‐methylpiperazinium) with shear piezoelectricity are synthesized and the thin films orientating along the polarization direction are fabricated. These orientated films, characterized by numerous grains and compact grain boundaries, can effectively facilitate the grain boundary sliding to convert normal stress into shear stress, thus facilely activating the shear piezoelectricity. The resulting devices can accurately identify the position and type of ultrasound sources without the need for a complex acoustic impedance matching layer. Moreover, these devices can successfully sense delicate variations in momentum caused by table tennis balls. The findings open up a new pathway to utilize shear piezoelectricity that is normally considered unuseful of metal halides and other molecular piezoelectrics. [ABSTRACT FROM AUTHOR]

Phosphogypsum is a solid waste with great environmental stockpile pressure produced by the wet production of phosphoric acid. Although there are various methods to purify and utilize phosphogypsum, the means for environmentally friendly, low energy consumption, and high value-added utilization still need to be further explored. Here, CaSO4·2H2O crystal was directly purified and regulated from phosphogypsum by using the anti-solvent method. The antisolvent can be adsorbed in the c-axis direction of the crystal and further inhibit the growth rate in this direction, resulting in a change in the morphology of the crystal. By adjusting the polarity and chain length of the anti-solvent, the morphology of CaSO4·2H2O crystal can change from butterfly-like flake crystals to hexagonal prism-like crystals. When n-propanol with long chain was used as the anti-solvent, the morphology of the CaSO4·2H2O crystal showed a hexagonal prism with a specific surface area of 19.98 m2/g and a Cu2+ loading efficiency of 52.67%. The encouraging results open up new possibilities for the application of phosphogypsum. [ABSTRACT FROM AUTHOR]

Copyright of Rare Metals is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)