Enhanced Acoustoelectric Energy Harvesting with TiCT MXene in an All-Fiber Nanogenerator.

Materials and devices that harvest acoustic energy can enable autonomous powering of microdevices and wireless sensors. However, traditional acoustic energy harvesters rely on brittle piezoceramics, which have restricted their use in wearable electronic devices. To address these limitations, this study involves the fabrication of acoustic harvesters using electrospinning of the piezoelectric polymer PVDF-TrFE onto fabric-based electrodes.

Piezo-to-piezo (P2P) conversion: simultaneous β-phase crystallization and poling of ultrathin, transparent and freestanding homopolymer PVDF films MHz-order nanoelectromechanical vibration.

An unconventional yet facile low-energy method for uniquely synthesizing neat poly(vinylidene fluoride) (PVDF) films for energy harvesting applications by utilizing nanoelectromechanical vibration through a 'piezo-to-piezo' (P2P) mechanism is reported. In this concept, the nanoelectromechanical energy from a piezoelectric substrate is directly coupled into another polarizable material (, PVDF) during its crystallization to produce an optically transparent micron-thick film that not only exhibits strong piezoelectricity, but is also freestanding-properties ideal for its use for energy harvesting, but which are difficult to achieve through conventional synthesis routes. We show, particularly through characterization, that the unprecedented acceleration associated with the nanoelectromechanical vibration in the form of surface reflected bulk waves (SRBWs) facilitates preferentially-oriented nucleation of the ferroelectric PVDF β-phase, while simultaneously aligning its dipoles to pole the material through the SRBW's intense native evanescent electric field .

The Acoustophotoelectric Effect: Efficient Phonon-Photon-Electron Coupling in Zero-Voltage-Biased 2D SnS for Broad-Band Photodetection.

Two-dimensional (2D) layered metal dichalcogenides constitute a promising class of materials for photodetector applications due to their excellent optoelectronic properties. The most common photodetectors, which work on the principle of photoconductive or photovoltaic effects, however, require either the application of external voltage biases or built-in electric fields, which makes it challenging to simultaneously achieve high responsivities across broad-band wavelength excitation─especially beyond the material's nominal band gap─while producing low dark currents. In this work, we report the discovery of an intricate phonon-photon-electron coupling─which we term the effect─in SnS that facilitates efficient photodetection through the application of 100 MHz order propagating surface acoustic waves (SAWs).