Publications

Liquid–solid triboelectric nanogenerator (L–S TENG) is one of the major techniques to collect energy from tiny liquids, while the saturated charge density at the L–S interface is the key element to decide its performance. Here, we found that the saturated charge density of L–S contact electrification (CE) can be further increased under the illumination of an ultraviolet (UV) light. The fluorine-containing polymers and SiO2 are chosen as the electrification materials and with and without UV illumination on the L–S TENG. A series of experiments have been done to rule out the possible influences of anion generation, chemical change of solid surface, ionization of water, and so on. Therefore, we proposed that electrons belonging to water molecules can be excited to high energy states under UV illumination, which then transfer to solid surface and captured by the solid surface. Finally, a photoexcited electron transfer model is proposed to explain the enhancement of CE under the UV illumination. This work not only helps to further understand CE at L–S interface, but also offers an approach to further enhance the performance of L–S TENG, which can promote the TENG applications in the field of microfluidic systems, liquid energy harvesting, and droplet sensory.

A new approach for fabrication of a long-term and recoverable antimicrobial nanostructure/textile hybrid without increasing the antimicrobial resistance is demonstrated. Using in situ synthesized Ag nanoparticles (NPs) anchored on ZnO nanowires (NWs) grown on textiles by a 'dip-in and light-irradiation' green chemical method, we obtained ZnONW@AgNP nanocomposites with small-size and uniform Ag NPs, which have shown superior performance for antibacterial applications. These new Ag/ZnO/textile antimicrobial composites can be used for wound dressings and medical textiles for topical and prophylactic antibacterial treatments, point-of-use water treatment to improve the cleanliness of water and antimicrobial air filters to prevent bioaerosols accumulating in ventilation, heating, and air-conditioning systems.

Abstract As an emerging harvester for mechanical energy, the ultrahigh and unstable voltage and low surface charge density have limited the practical applications of triboelectric nanogenerators (TENGs). Herein, a charge pumping technology is demonstrated for sliding‐mode TENG with voltage stabilization and enhanced current by utilizing unfixed shuttling charges to generate electricity. A voltage booster circuit and a switch circuit are incorporated to elevate charge density and reduce high output voltage, respectively. With this technology, output electricity can be doubled owing to its two conduction domains and the voltage is outputted in an approximately direct‐current form. Moreover, a reduction of 63.9% in voltage fluctuation and an elevation of 43.4% in current are achieved, and an ultrahigh charge density is obtained up to 1328 µC m −2 . This sliding charge pump technology is fundamentally different from traditional ones, providing insight into enhancing the output of TENG and offering a new high‐output energy harvesting strategy.

'Peltier Cooler' published in 'Encyclopedia of Nanotechnology'

Mechanochemistry has been studied for some time, but research on the reactivity of charges exchanged by contact-electrification (CE) during mechanical stimulation remains scarce. Here, we demonstrate that electrons transferred during the CE between pristine dielectric powders and water can be utilized to directly catalyze reactions without the use of conventional catalysts. Specifically, frequent CE at Fluorinated Ethylene Propylene (FEP) - water interface induces electron-exchanges, thus forming reactive oxygen species for the degradation of an aqueous methyl orange solution. Contact-electro-catalysis, by conjunction of CE, mechanochemistry and catalysis, has been proposed as a general mechanism, which has been demonstrated to be effective for various dielectric materials, such as Teflon, Nylon-6,6 and rubber. This original catalytic principle not only expands the range of catalytic materials, but also enables us to envisage catalytic processes through mechano-induced contact-electrification.

'Protein Nano-crystallization' published in 'Encyclopedia of Nanotechnology'

Tribotronics is a new field developed by coupling triboelectricity and semiconductor, which can drive triboelectric‐charge‐controlled optoelectronic devices by further introducing optoelectronics. In this paper, a tribotronic phototransistor (TPT) is proposed by coupling a field‐effect phototransistor and a triboelectric nanogenerator (TENG), in which the contact‐induced inner gate voltage by the mobile frictional layer is used for modulating the photodetection characteristics of the TPT. Based on the TPT, alternatively, a coupled energy‐harvester (CEH) is fabricated for simultaneously scavenging solar and wind energies, in which the output voltage on the external resistance from the wind driven TENG is used as the gate voltage of the TPT for enhancing the solar energy conversion. As the wind speed increases, the photovoltaic characteristics of the CEH including the short‐circuit current, open‐circuit voltage, and maximal output power have been greatly enhanced. This work has greatly expanded the functionality of tribotronics in photodetection and energy harvesting, and provided a potential solution for highly efficient harvesting and utilizing multitype energy.

'Propylene Glycol Methyl Ether Acetate (PGMEA)' published in 'Encyclopedia of Nanotechnology'

In this paper, the factors that determine the power output of a piezoelectric nanowire (NW) nanogenerator (NG) have been analyzed. The output current is the sum of those contributed by all of the NWs while the output voltage is determined by the voltage generated by a single NW, the capacitance of the NW array and the system, and the contact resistance. By growing uniform ZnO NWs with diameters of ∼100nm and lengths of ∼5μm, the output current density and output voltage of the NG was improved to ∼8.3μA∕cm2 and 10mV, respectively, which are 20–30 times higher than that we previously reported. A power generation density of ∼83nW∕cm2 is achieved by using a single layer NW NG.

In this investigation, we report the flexoelectricity-enhanced photovoltaic (FPV) effect in a flexible Pb(Zr0.52Ti0.48)O3 nanowire (PZT NW) array/PDMS (polydimethylsiloxane) nanocomposite. The simulation result of density functional theory (DFT) indicated that the FPV effect in PZT NWs can be greatly affected by the interactions of the strain gradients with the internal field generated by self-polarization. We found that when the nanocomposite film was curved down, the photovoltaic current of the aligned PZT-NW/PDMS composite increased by 84.6-fold and 27.6-fold compared with the PZT-nanoparticles/PDMS and randomly aligned PZT-NW/PDMS nanocomposites at the same curvature, respectively. This is mainly ascribed to the increased flexoelectricity in the aligned PZT-NW/PDMS nanocomposite. This study will contribute to a full understanding of the influence of nanoparticle shape on the flexophotovoltaic effect of nanocomposites. It will have potential use in nanocomposites for the study of the FPV effect and associated applications.