Publications

Abstract As an emerging technology for energy harvesting and distributed power supply, triboelectric nanogenerators are mainly based on a dielectric capacitive structure. Here, a new mechanism by introducing an oil phase into a water–solid interface is demonstrated for energy harvesting based on electric double layer (EDL) capacitance. Through squeezing and releasing oil droplets on a dielectric surface in water environment, charge transfer is observed in the back electrode accompanying the movement of the oil–water–solid three‐phase line. The charge transfer is mainly attributed to the effect that the oil phase sweeps away ions near the dielectric surface in the EDL due to the discrepancy of EDL between water–solid and oil–solid interfaces. Under the water environment, the device is shown to be capable of direct energy harvesting and self‐powered sensing without costly packaging. As a new working mode relying on EDL, it allows developing nanogenerators adaptive to severe environments even underwater with low friction and wear, and narrowing the gap between energy harvesting devices and electro‐chemical devices. Through further enhanced EDL, it is reasonable to anticipate devices with an ultrahigh charge density comparable with EDL super capacitors, opening up an avenue toward new nanogenerators with overwhelming performance for practical applications ranging from blue energy harvesting to electro‐catalysis.

Abstract Liquid droplet nanogenerators showcase significant potential in harvesting energy from natural sources rain or industrial processes involving liquids. However, their utility is limited by their low power output and the complexity of methods required to enhance efficiency. Here, the study presents an enhanced performance of the LSTENG, which leverages polarized surface to significantly enhance its output efficiency. The improved LSTENG design highlights with utilizing the effects of interface polarization through strategically contrasting dielectric distributions and the approach of ion surface treatment to modify the interface, achieves a superior instantaneous peak power density of 448 W m −2 . This performance doubles the previous highest research benchmark, and it is attained without employing any pre‐charge techniques. This new approach represents a pivotal advancement in energy harvesting landscapes, positioning LSTENG as a highly promising energy source with a greatly expanded range of potential applications.

Micro total analysis system (μTAS) is one of the important tools for modern analytical sciences. In this paper, we not only propose the concept of integrating the self-powered triboelectric microfluidic nanosensor (TMN) with μTAS, but also demonstrate that the developed system can be used as an in situ tool to quantify the flowing liquid for microfluidics and solution chemistry. The TMN automatically generates electric outputs when the fluid passing through it and the outputs are affected by the solution temperature, polarity, ionic concentration, and fluid flow velocity. The self-powered TMN can detect the flowing water velocity, position, reaction temperature, ethanol, and salt concentrations. We also integrate the TMNs in a μTAS platform to directly characterize the synthesis of Au nanoparticles by a chemical reduction method.

Single-walled carbon nanotubes (SWNTs) were effectively dispersed and functionalized by wrapping with single-stranded DNA (ssDNA). The ssDNA−SWNTs attach strongly on glass substrate and easily form a uniform film, making it possible for electrochemical analysis and sensing. The film was fabricated into a working electrode, which exhibited good electrochemical voltammetric properties, such as flat and wide potential window, well-defined quasi-reversible voltammetric responses, and quick electron transfer for a Fe(CN)63-/Fe(CN)64 system, indicating that the ssDNA−SWNTs film should be a good analytical electrode for electrochemical detection or sensing. This was demonstrated by highly selective and sensitive detection of a low concentration of dopamine in the presence of excess ascorbic acid.

Abstract The surface charge density and the output impedance of triboelectric nanogenerators (TENGs) are two critical factors for TENGs to speed up their commercialization, so it is important to explore unique methods to reduce the output impedance and increase the surface charge density. Here, an approach is demonstrated to effectively boost the output performance of TENG while reducing the output impedance of TENGs by utilizing grating‐electrode‐enabled surface plasmon excitation. A sustainable and enhanced output performance of about 40 µA (short‐circuit current) and 350 V (peak‐to‐peak voltage at a resistance of 10 MΩ) is produced via grating‐coupled surface plasmon resonance on the TENG with the aluminum grating electrode in the line density of 600 lines mm −1 , and it delivers a peak output power of 3.6 mW under a loading resistance of 1 MΩ, giving over 4.5‐fold enhancement in output power and a 75% reduction in the output impedance. Finally a self‐powered ultrasonic ranging system is utilized to verify the capability of the TENG in powering portable electrics.

'Plasmonics for Solar Cells' published in 'Encyclopedia of Nanotechnology'

Abstract Making use of water wave energy at large is one of the most attractive, low‐carbon, and renewable ways to generate electric power. The emergence of triboelectric nanogenerator (TENG) provides a new approach for effectively harvesting such low‐frequency, irregular, and “random” energy. In this work, a TENG array consisting of spherical TENG units based on spring‐assisted multilayered structure is devised to scavenge water wave energy. The introduction of spring structure enhances the output performance of the spherical TENG by transforming low‐frequency water wave motions into high‐frequency vibrations, while the multilayered structure increases the space utilization, leading to a higher output of a spherical unit. Owing to its unique structure, the output current of one spherical TENG unit could reach 120 µA, which is two orders of magnitude larger than that of previous rolling spherical TENG, and a maximum output power up to 7.96 mW is realized as triggered by the water waves. The TENG array fabricated by integrating four units is demonstrated to successfully drive dozens of light‐emitting diodes and power an electronic thermometer. This study provides a new type of TENG device with improved performance toward large‐scale blue energy harvesting from the water waves.

Selective doping and band-offset in core-shell nanowire (NW) structures using germanium (Ge)/ silicon (Si) can realize a type of high electron mobility transistor (HEMT) structure in one-dimensional NWs by separating the carrier transport region from the impurity-doped region. Precise analysis, using Raman spectroscopy of the Ge optical phonon peak, can distinguish three effects: the phonon confinement effect, the stress effect due to the heterostructures, and the Fano effect. Using these techniques, we obtained conclusive evidence of hole gas accumulation in Ge/Si core-shell NWs. The control of hole gas concentration can be realized by changing the B doping concentration in the Si shell.

Abstract The human metabolome provides a window into the mechanisms and biomarkers of various diseases. However, because of limited availability, many sample types are still difficult to study by metabolomic analyses. Here, we present a mass spectrometry (MS)-based metabolomics strategy that only consumes sub-nanoliter sample volumes. The approach consists of combining a customized metabolomics workflow with a pulsed MS ion generation method, known as triboelectric nanogenerator inductive nanoelectrospray ionization (TENGi nanoESI) MS. Samples tested with this approach include exhaled breath condensate collected from cystic fibrosis patients as well as in vitro - cultured human mesenchymal stromal cells. Both test samples are only available in minimum amounts. Experiments show that picoliter-volume spray pulses suffice to generate high-quality spectral fingerprints, which increase the information density produced per unit sample volume. This TENGi nanoESI strategy has the potential to fill in the gap in metabolomics where liquid chromatography-MS-based analyses cannot be applied. Our method opens up avenues for future investigations into understanding metabolic changes caused by diseases or external stimuli.