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Serious climate changes and energy-related environmental problems are currently critical issues in the world. In order to reduce carbon emissions and save our environment, renewable energy harvesting technologies will serve as a key solution in the near future. Among them, triboelectric nanogenerators (TENGs), which is one of the most promising mechanical energy harvesters by means of contact electrification phenomenon, are explosively developing due to abundant wasting mechanical energy sources and a number of superior advantages in a wide availability and selection of materials, relatively simple device configurations, and low-cost processing. Significant experimental and theoretical efforts have been achieved toward understanding fundamental behaviors and a wide range of demonstrations since its report in 2012. As a result, considerable technological advancement has been exhibited and it advances the timeline of achievement in the proposed roadmap. Now, the technology has reached the stage of prototype development with verification of performance beyond the lab scale environment toward its commercialization. In this review, distinguished authors in the world worked together to summarize the state of the art in theory, materials, devices, systems, circuits, and applications in TENG fields. The great research achievements of researchers in this field around the world over the past decade are expected to play a major role in coming to fruition of unexpectedly accelerated technological advances over the next decade.

A corona discharge treatment (CDT) is utilized to maximize the performance of triboelectric nanogenerators (TENGs) by injecting extra electrons into the negative tribomaterials. Increased performance of CDT TENGs, however, exhibits rapid degradation due to the electron dissipation by air moisture or thermal emission. To overcome such drawbacks and circumvent such dissipation, the source of charges should be replaced with ionic charges. This study reports a Ag nanowires (NWs)‐embedded laminating structure (AeLS) with a unique fabrication procedure for ionic charge injection by CDT. The injection of ions is achieved by interlayer‐CDT (i‐CDT), in which positive charges are dissipated by Ag NWs, and the opposite negative ions can remain on the outmost surface. The AeLS TENGs with i‐CDT exhibit high performance, long‐term stability, and durability. It shows voltage, current, and maximum power outputs of 380 V, 15 µA, and 827 mW m−2, respectively. As a practical demonstration, rotational TENG integrated with a direct discharge system is realized, and its current and voltage reach 7.4 mA and 7800 V, respectively. This work can pave the way for the design of ion‐based TENGs with high performance and long‐lasting retention of triboelectric charges. [ABSTRACT FROM AUTHOR]

As state-of-the-art electronic chips were miniaturized to its limit, many small dimension issues, such as crosstalk noise, parasite capacitance, and tunneling of charges, emerged. Studying such issues shall be of interest to the research and industry field. Here, we studied the electrical behavior of electrons injected in an array of nanostructures embedded on Al2O3 dielectrics. Our multi-stack device comprised Au nanoclusters, tunneling and blocking Al2O3 oxide layers, and a Si substrate. The electrons were injected by applying a bias at the top of the atomic force microscopy tip in contact while grounding the Si substrate. Its retention and diffusion behaviors were observed by measuring the contact potential difference (CPD). The measured CPD data with time were well fitted to the bi-exponential function, which had two time constants τ1 and τ2. It indicated that at least two dominant tunneling mechanisms existed, so it was confirmed with I–V measurement using a simple tunneling device (Pt/Al2O3/Si structure). This work may provide a tool for analysis of charge transportation in a miniaturized nanostructure. [ABSTRACT FROM AUTHOR]