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A ZnO NR decorated PVDF-MXene composite NF EMI shielding material exhibiting superb absorption dominant EMI SE, flexibility, and multi-functionality.

A flexible piezoelectric composite is composed of a polymer matrix and piezoelectric ceramic fillers to achieve good mechanical flexibility and processability. The overall piezoelectric performance of a composite is largely determined by the piezoelectric filler inside. Thus, different dispersion methods and additives that can promote the dispersion of piezoelectric ceramics and optimal composite structures have been actively investigated. However, relatively few attempts have been made to develop a filler that can effectively contribute to the performance enhancement of piezoelectric devices. In the present work, we introduce the fabrication and performance of the composite piezoelectric devices composed of Li-doped ZnO nanowires (Li: ZnO NWs) grown on the surface of MXene (Ti

In this study, we examined the dependence of surface morphology and spin Seebeck effect (SSE) voltages on the poly[vinylpyrrolidone] (PVP) concentration in polycrystalline Y3Fe5O12 (YIG) ultrathin films on a silicon substrate synthesized by metal-organic decomposition followed by a crystallization process. During fabrication, PVP concentrations of 0.5–2 g were used while all other conditions remained fixed. Atomic force microscopy and grazing incidence X-ray diffraction (XRD) measurements revealed a strong dependence of crystallinity and sample morphology on PVP concentration. The 1-g PVP sample had the smoothest surface, with a root mean square roughness of 0.2 nm, as well as superior bulk uniformity with respect to the shape and intensity of XRD reflection peaks. This was confirmed by scanning electron microscopy measurements of a cross-section of the sample that revealed a uniform film without pores. SSE measurements were performed to obtain the output SSE voltages (VSSE) of all samples, to which a platinum layer was added as a spin-detection layer. Repeatedly, the 1-g PVP sample had the best performance, demonstrating the importance of film crystallinity and morphology in the spin-to-charge conversion efficiency of YIG films.

Recently, the inherent piezoelectric properties of the 2D transition-metal dichalcogenides (TMDs) tin monosulfide (SnS) and tin disulfide (SnS2) have attracted much attention. Thus the piezoelectricity of these materials has been theoretically and experimentally investigated for energy-harvesting devices. However, the piezoelectric output performance of the SnS2- or SnS-based 2D thin film piezoelectric nanogenerator (PENG) is still relatively low, and the fabrication process is not suitable for practical applications. Here we report the formation of the SnS2/SnS heterostructure thin film for the enhanced output performance of a PENG using atomic layer deposition (ALD). The piezoelectric response of the heterostructure thin film was increased by ∼40% compared with that of the SnS2 thin film, attributed to large band offset induced by the heterojunction formation. Consequently, the output voltage and current density of the heterostructure PENG were 60 mV and 11.4 nA/cm2 at 0.6% tensile strain, respectively. In addition, thickness-controllable large-area uniform thin-film deposition via ALD ensures that the reproducible output performance is achieved and that the output density can be lithographically adjusted depending on the applications. Therefore, the SnS2/SnS heterostructure PENG fabricated in this work can be employed to develop a flexible energy-harvesting device or an attachable self-powered sensor for monitoring pulse and human body movement.

Recently, the inherent piezoelectric properties of the 2D transition-metal dichalcogenides (TMDs) tin monosulfide (SnS) and tin disulfide (SnS

Recently, human motion and respiration monitoring sensors have attracted significant research attention in the field of wearable electronics and healthcare applications. Fiber-based electronic sensors demonstrate significant potential for such applications due to their flexibility. However, the superior flexibility of fiber-based sensors is generally limited due to the partial use of rigid elements such as metal electrode layers. In this paper, a simple method is presented for the fabrication of all-nanofiber multifunctional sensors, which consist of triboelectric (TE), piezoresistive (PR), and thermoresistive (TR) sensing elements and demonstrate superior flexibility, excellent wearability, and multifunctionality. The TE sensing unit was fabricated by integrating two triboelectrically dissimilar nanofiber surfaces using a polymer mesh separator, for the formation of internal macro-scale air gaps; followed by the electrical polarization of nanofibers. The TR and PR sensing elements were realized using vapor-phase polymerized fiber electrode layers. Using the sensor developed in this study, different motions and breathing frequencies can be individually or simultaneously detected using the TE, PR, and TR sensing elements. This work therefore presents a novel scheme for human motion sensors and breathing sensors, which are widely applicable to wearable electronics, healthcare monitoring, and human-machine interfaces.

To date, several attempts have been made to improve the performance of triboelectric nanogenerators (TENGs). Although notable advancements have been made in the output power density, it is still relatively low and further improvement in the output power density has been limited by air breakdown issue. In this work, we proposed preferable composite structures and an electrical activation method to maximize the output performance of TENGs by adopting ferroelectric composite interfacial layer. Specifically, by doping Nylon 11 with Poly (methyl methacrylate) - PMMA, we intensified the positive triboelectricity of Nylon 11 and simultaneously improved its physical durability. The negative triboelectricity of PVDF-TrFE was also enhanced by compositing with ZrO2 nanoparticles (NPs). Triboelectricity of both polymer composites was further boosted by polarizing them in favorable direction. Therefore, high frictional surface charge density of 220 μC/m2 was achieved in short-circuit condition, effectively promoting charge outputs. Consequently, the open circuit voltage and short circuit current density of ~500 V and ~500 μA cm−2 were achieved, respectively, exhibiting a remarkable output power density of ~42 mW cm−2.