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Advancements in wearable electronics and Internet of Things (IoT) sensors have catalyzed the need for effective micro‐energy harvesting. Piezoelectric nanogenerators (PENGs) are ideal due to their high conversion efficiency and durability. However, the contrast between the high piezoelectric coefficients of brittle inorganic ceramics and the lower coefficients of superior flexibility and biocompatibility of organic polymers poses a significant challenge. This work introduces a novel multilayer composite PENG, integrating a single‐crystal BaTiO3 (BTO) film between poly(vinylidene fluoride‐co‐trifluoroethylene) (PVDF‐TrFE) layers. The PVDF‐TrFE/BTO/PVDF‐TrFE PENGs demonstrate substantially improved energy harvesting performance, with outputs reaching up to 15.1 V, 2.39 µA, and power density of 17.33 µW cm−2 during bending deformation. This power density represents a significant increase compared to pure PVDF‐TrFE and nanoparticle BTO‐doped PVDF‐TrFE PENGs. Durability tests show consistent performance, with a stable ∼15.0 V output across 2000 bending cycles. Additionally, when attached to the human body, these PENGs efficiently convert body motions into electrical responses. This work demonstrates a significant enhancement in the performance of PENGs using sandwich‐structured composite of PVDF‐TrFE and freestanding single‐crystal BTO films, showing its potential to address the power requirements of wearable and flexible electronic devices. [ABSTRACT FROM AUTHOR]

In this paper, isotropic copper nanoparticles (CuNPs) were successfully sythesized by using Cu(CH3COO)2 and ascorbic acid in absolute ethanol solution. With the addition of polyvinylpyrrolidone (PVP) protective additive, the size distribution range of the synthesized CuNPs was significantly reduced from 650±415 nm to 51±12 nm. Electrodeposition analysis revealed that PVP could greatly suppress the reduction of Cu but had no prominent effects on the deposition mechanism. Based on the potentiostatic deposition results, a growth model was proposed to improve the applicability of the Scharifker‐Hills model by considering both the surface inhibition effect and the mass diffusion during the growth process of Cu nuclei. The experimental data fitted well with the prediction results from the proposed model, indicating that the electrodeposition of Cu followed the progressive nucleation process. The PVP additive could inhibit the deposition and growth of Cu by increasing the surface inhibition for cation incorporation on the nuclei, which was probably the main reason for the refinement of the sythesized CuNPs. Our findings can provide insights for the preparation of metallic nanoparticles and the understanding of their deposition mechanism. [ABSTRACT FROM AUTHOR]

Keywords: nanoparticles; electrochemistry; redox chemistry; nucleation mechanism; growth model EN nanoparticles electrochemistry redox chemistry nucleation mechanism growth model 756 756 1 03/13/21 20210301 NES 210301 B The Cover Feature b illustrates a wet-chemical synthesis method using Cu(CH SB 3 sb COO) SB 2 sb and ascorbic acid in absolute ethanol solution for the preparation of isotropic copper nanoparticles. Nanoparticles, electrochemistry, redox chemistry, nucleation mechanism, growth model. [Extracted from the article]