Publications

Real-time monitoring of microscopic chemical reactions offers valuable insight into reaction mechanisms, intermediate species, and the reaction kinetics involved. Mainstream electrochemical and chromatographic techniques are often complex, low-sensitivity, failing to capture transient phenomena or distinguish similar chemical species within the reaction, limiting their accessibility for real-time and continuing monitoring. Here, high-resolution interface charge transfer mapping (ICTM) generated by liquid-solid contact electrification is used in situ for continuously monitoring potential chemical changes in the reactions. As liquid reactants slide dropwise over time along an insulating reclined plane, the ICTMs along the sample trajectory over time are recorded and is used to analysis chemical changes within the reactions. By means of time-resolved ICTM measurements at statically charged dielectric surface, we have probed the dynamic evolution of redox reactions, tracked the organocatalytic reactions, and evaluated the agglomeration state of metal catalysts with a time resolution on the scale of seconds.

A self-powered triboelectric auditory sensor is designed for human-robot interactions.

Two-dimensional (2D) layered piezoelectric nanomaterials are attractive for application in mechanical energy-harvesting devices. In this study, layered 2D nanosheets, h-BN and MX2 (M = Mo or W; X = S, Se, or Te), are deposited on a silicon substrate to form cantilever energy harvesters. Using density functional theory (DFT) and molecular dynamics (MD) calculations, the effect of the substrate for energy harvesting is studied. The substrate provides 2D layers with stable support while maintaining effective energy harvesting. MD results indicate that the electromechanical conversion energy has contributions from piezoelectricity and flexoelectricity, but the latter is negligible due to small strain gradients for bending-operated nanoharvesters. It is shown that the out-of-plane piezoelectric constants are substantially larger than their in-plane piezoelectric counterparts. The output power is calculated for a substrate-supported nanogenerator. This work provides an atomistic study of piezoelectricity and a new strategy to implement 2D materials in nano energy harvesters.

A novel PVDF–PZT nanocomposite film has been proposed and used as a piezoseparator in self-charging power cells (SCPCs). The structure, composed of poly(vinylidene fluoride) (PVDF) and lead zirconate titanate (PZT), provides a high piezoelectric output, because PZT in this nanocomposite film can improve the piezopotential compared to the pure PVDF film. The SCPC based on this nanocomposite film can be efficiently charged up by the mechanical deformation in the absence of an external power source. The charge capacity of the PVDF–PZT nanocomposite film based SCPC in 240 s is ∼0.010 μA h, higher than that of a pure PVDF film based SCPC (∼0.004 μA h). This is the first demonstration of using PVDF–PZT nanocomposite film as a piezoseparator for SCPC, and is an important step for the practical applications of SCPC for harvesting and storing mechanical energy.

With the great progress in human activities and production technologies, the waste inevitably produced causes not only environmental pollution but also resource waste; meanwhile, the mobile and portable electronic devices urgently need a distributed and sustainable energy source to ensure their stable operation. Here, the waste pollutants (milk cartons) generated from daily life, commonly associated with environmental concerns, are instead identified as an available resource for preparing an emerging energy harvester (triboelectric nanogenerator, TENG), which can convert ubiquitous mechanical energy into electric power. Consequently, based on the waste material, the initial charge density of the TENG is as low as 0.035 mC m–2, which can be tremendously improved to 1.00 mC m–2 through combining a charge excitation circuit, achieving efficient energy harvesting. In addition, compared to the common dielectric film, the waste material can reduce the cost and simplify the process of the preparation of TENG. This work provides not only an innovative approach to simultaneously realize environmental protection and energy harvesting but also more material choice for the preparation of a low-cost and high-performance TENG.

High performance direct current (DC) textile power supply is an urgent demand for wearable electronics. Herein, we present a wearable DC textile power woven by P/N-type organic semiconductor fibers based...

In article number 1400392, Chuan-Pu Liu and co-workers report the synthesis of Si-doped GaN nanowire arrays with various carrier concentrations to investigate the impact of carrier screening on the output performance of alternating-current (AC) vertical integrated nanogenerators (VINGs). The output voltage and current density of AC VINGs strongly decrease with increasing doping concentration. Consequently, AC VINGs can be optimized if they are composed of piezotronic materials with the lowest possible carrier concentration to prevent the screening effect.

The computer keyboard is one of the most common, reliable, accessible, and effective tools used for human--machine interfacing and information exchange. Although keyboards have been used for hundreds of years for advancing human civilization, studying human behavior by keystroke dynamics using smart keyboards remains a great challenge. Here we report a self-powered, non-mechanical-punching keyboard enabled by contact electrification between human fingers and keys, which converts mechanical stimuli applied to the keyboard into local electronic signals without applying an external power. The intelligent keyboard (IKB) can not only sensitively trigger a wireless alarm system once gentle finger tapping occurs but also trace and record typed content by detecting both the dynamic time intervals between and during the inputting of letters and the force used for each typing action. Such features hold promise for its use as a smart security system that can realize detection, alert, recording, and identification. Moreover, the IKB is able to identify personal characteristics from different individuals, assisted by the behavioral biometric of keystroke dynamics. Furthermore, the IKB can effectively harness typing motions for electricity to charge commercial electronics at arbitrary typing speeds greater than 100 characters per min. Given the above features, the IKB can be potentially applied not only to self-powered electronics but also to artificial intelligence, cyber security, and computer or network access control.

Abstract Triboelectric nanogenerators (TENGs) stand out for their wearability, portability, and versatility as a promising energy‐harvesting technology and facilitate their wide self‐powered intelligent applications in various medical fields. However, there are few studies on sterilization and mite removal. Herein, a wearable and antibacterial sandwich‐structured single‐electrode chitosan‐hydroxyethyl cellulose‐pectin (CHP) ‐ polypyrrole (PPy) ‐ CHP( CHP‐PPy‐CHP) triboelectric nanogenerator (CPC‐TENG) by utilizing CHP composite film as the triboelectric layer is proposed and developed. The CPC‐TENG exhibits a maximum short‐circuit current density of 12.99 µA cm −2 , resulting in a high instantaneous power of 287 µW during one cycle. It is found that the prepared CPC‐TENG with 11 wt% chitosan fillers has an antibacterial effectiveness of 92.86% against Escherichia coli . Moreover, The CPC‐TENG can be used as a self‐powered human motion monitoring sensor with stable and sensitive response to continuous motion. The antimicrobial and sensing properties of CPC‐TENG demonstrate the enormous potential of the intelligent health monitoring for medical and health.

Abstract Electrostatic breakdown is a common but generally negative physical phenomenon. Here, efficient conversion of mechanical energy to electric power is achieved by enhanced direct‐current triboelectric nanogenerator (DC‐TENG) based on contact electrification and electrostatic breakdown. By verifying the high temperature can not only improve the triboelectric charge density but also enhance electrostatic breakdown of air dielectric due to thermionic emission of electrons and avalanche breakdown effect. Meanwhile an appropriate low atmosphere pressure is another favorable factor to air breakdown in DC‐TENG. As a result, its output power density is improved by three orders of magnitude at 473 K and 300 Pa compared to that at 298 K and standard atmosphere pressure. These findings not only provide a new paradigm to design high‐performance TENG, but realize efficiently harvesting mechanical energy and thermal energy in one device by coupling the two kinds of physical effects.