Publications

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Abstract A method of fabricating horizontally aligned ZnO nanowire (NW) arrays with full control over the width and length is demonstrated. A cross‐sectional view of the NWs by transmission electron microscopy shows a “mushroom‐like” structure. Novel monolithic multisegment superstructures are fabricated by making use of the lateral overgrowth. Ultralong horizontal ZnO NWs of an aspect ratio on the order of ten thousand are also demonstrated. These horizontal NWs are lifted off and transferred onto a flexible polymer substrate, which may have many great applications in horizontal ZnO NW‐based nanosensor arrays, light‐emitting diodes, optical gratings, integrated circuit interconnects, and high‐output‐power alternating‐current nanogenerators.

This article describes a simple, cost-effective, and scalable approach to fabricate a triboelectric nanogenerator (NG) with ultrahigh electric output. Triggered by commonly available ambient mechanical energy such as human footfalls, a NG with size smaller than a human palm can generate maximum short-circuit current of 2 mA, delivering instantaneous power output of 1.2 W to external load. The power output corresponds to an area power density of 313 W/m(2) and a volume power density of 54,268 W/m(3) at an open-circuit voltage of ~1200 V. An energy conversion efficiency of 14.9% has been achieved. The power was capable of instantaneously lighting up as many as 600 multicolor commercial LED bulbs. The record high power output for the NG is attributed to optimized structure, proper materials selection and nanoscale surface modification. This work demonstrated the practicability of using NG to harvest large-scale mechanical energy, such as footsteps, rolling wheels, wind power, and ocean waves.

The judicious positioning of rationally designed monodisperse plasmonic NPs in the ETL affords effective tailoring of the carrier dynamics of PSCs.

The recent intensification of the study of contact-electrification at water-solid interfaces and its role in physicochemical processes lead to the realization that electron transfers during water-solid contact-electrification can drive chemical reactions. This mechanism, named contact-electro-catalysis (CEC), allows chemically inert fluorinated polymers to act like single electrode electrochemical systems. This study shows hydrogen peroxide (H2 O2 ) is generated from air and deionized water, by ultrasound driven CEC, using fluorinated ethylene propylene (FEP) as the catalyst. For a mass ratio of catalyst to solution of 1:10000, at 20 °C, the kinetic rate of H2 O2 evolution reaches 58.87 mmol L-1 gcat-1 h-1 . Electron paramagnetic resonance (EPR) shows electrons are emitted in the solution by the charged FEP, during ultrasonication. EPR and isotope labelling experiments show H2 O2 is formed from hydroxyl radicals (HO• ) or two superoxide radicals (O2•- ) generated by CEC. Finally, it is traditionally believed such radicals migrate in the solution by Brownian diffusion prior to reactions. However, ab-initio molecular dynamic calculations reveal the radicals can react by exchanging protons and electrons through the hydrogen bonds network of water, i.e., owing to the Grotthuss mechanism. This mechanism can be relevant to other systems, artificial or natural, generating H2 O2 from air and water.

Abstract Stretchable triboelectric nanogenerators have attracted increasing interests in the field of wearable electronics. In this work, a stretchable and flexible triboelectric nanogenerator (SF‐TENG) with a ladder structure that consists of several single‐electrode TENG units on the elastic rubber substrate is developed. The structural design of the ladder‐shaped SF‐TENG is found to greatly improve the mechanical flexibility and stretching ability under small external force, and it works well even under the elongation of 120% and curvature of 90º. The SF‐TENG with optimized structure can have excellent linear response to tensile force and act as a strain sensor. The sensitivities of output voltage to tensile force and tensile displacement can reach 2.01 V N −1 and 0.0412 V mm −1 , respectively. Moreover, a SF‐TENG‐based data glove is fabricated to demonstrate the potential application of such TENG in the human–machine interaction through the stone–paper–scissors game.

As an important part of natural resources, islands support the marine economy and build a blue barrier for marine ecological civilization. However, the power supply on these islands is difficult, limiting the development of marine internet of things (IoTs). In order to break the status quo, this work applies triboelectric nanogenerators (TENGs) to island power supply and ecological monitoring. A spherical TENG with two multilayered helical units is designed to harvest water wave energy, in which the space utilization rate reaches 92.5%. Then a charge shuttling mechanism is developed to improve the electrical output. The output current and power of a single TENG without power management reach 200.3 µA and 16.2 mW respectively, corresponding to a peak power density of 23.2 W m-3 . Moreover, a scheme of the power managed TENG is proposed for realizing large-scale wave energy harvesting. The TENG is demonstrated to successfully power a water quality detector, a Bluetooth thermo-hygrometer, and an intelligent wireless alarm system for remote environmental monitoring. This work not only proposes a new type of TENG for water wave energy harvesting with improved performance, but also provides a new strategy for intelligent ocean IoTs, which even contributes to the carbon neutralization.

The first triboelectric-nanogenerator (TENG)-based self-powered implantable drug-delivery system is presented. Pumping flow rates from 5.3 to 40 µL min-1 under different rotating speeds of the TENG are realized. The implantable drug-delivery system can be powered with a TENG device rotated by human hand motion. Ex vivo trans-sclera drug delivery in porcine eyes is demonstrated by utilizing the biokinetic energies of human hands.