Jinhui Nie

Self-Powered Electrostatic Filter with Enhanced Photocatalytic Degradation of Formaldehyde Based on Built-in Triboelectric Nanogenerators

Recently, atmospheric pollution caused by particulate matter or volatile organic compounds (VOCs) has become a serious issue to threaten human health. Consequently, it is highly desirable to develop an efficient purifying technique with simple structure and low cost. In this study, by combining a triboelectric nanogenerator (TENG) and a photocatalysis technique, we demonstrated a concept of a self-powered filtering method for removing pollutants from indoor atmosphere. The photocatalyst P25 or Pt/P25 was embedded on the surface of polymer-coated stainless steel wires, and such steel wires were woven into a filtering network. A strong electric field can be induced on this filtering network by TENG, while both electrostatic adsorption effect and TENG-enhanced photocatalytic effect can be achieved. Rhodamine B (RhB) steam was selected as the pollutant for demonstration. The absorbed RhB on the filter network with TENG in 1 min was almost the same amount of absorption achieved in 15 min without using TENG. Meanwhile, the degradation of RhB was increased over 50% under the drive of TENG. Furthermore, such a device was applied for the degradation of formaldehyde, where degradation efficiency was doubled under the drive of TENG. This work extended the application for the TENG in self-powered electrochemistry, design and concept of which can be possibly applied in the field of haze governance, indoor air cleaning, and photocatalytic pollution removal for environmental protection.

Self-Powered Microfluidic Transport System Based on Triboelectric Nanogenerator and Electrowetting Technique

Electrowetting technique is an actuation method for manipulating position and velocity of fluids in the microchannels. By combining electrowetting technique and a freestanding mode triboelectric nanogenerator (TENG), we have designed a self-powered microfluidic transport system. In this system, a mini vehicle is fabricated by using four droplets to carry a pallet (6 mm × 8 mm), and it can transport some tiny object on the track electrodes under the drive of TENG. The motion of TENG can provide both driving power and control signal for the mini vehicle. The maximum load for this mini vehicle is 500 mg, and its highest controllable velocity can reach 1 m/s. Freestanding TENG has shown excellent capability to manipulate microfluid. Under the drive of TENG, the minimum volume of the droplet can reach 70-80 nL, while the tiny droplet can freely move on both horizontal and vertical planes. Finally, another strategy for delivering nanoparticles to the designated position has also been demonstrated. This proposed self-powered transport technique may have great applications in the field of microsolid/liquid manipulators, drug delivery systems, microrobotics, and human-machine interactions.

Stretchable Triboelectric–Photonic Smart Skin for Tactile and Gesture Sensing

Smart skin is expected to be stretchable and tactile for bionic robots as the medium with the ambient environment. Here, a stretchable triboelectric-photonic smart skin (STPS) is reported that enables multidimensional tactile and gesture sensing for a robotic hand. With a grating-structured metal film as the bioinspired skin stripe, the STPS exhibits a tunable aggregation-induced emission in a lateral tensile range of 0-160%. Moreover, the STPS can be used as a triboelectric nanogenerator for vertical pressure sensing with a maximum sensitivity of 34 mV Pa-1 . The pressure sensing characteristics can remain stable in different stretching conditions, which demonstrates a synchronous and independent sensing property for external stimuli with great durability. By integrating on a robotic hand as a conformal covering, the STPS shows multidimensional mechanical sensing abilities for external touch and different gestures with joints bending. This work has first demonstrated a triboelectric-photonic coupled multifunctional sensing terminal, which may have great applications in human-machine interaction, soft robots, and artificial intelligence.

Self-Powered Electrostatic Adsorption Face Mask Based on a Triboelectric Nanogenerator

The physical filtration mechanism of a traditional face mask has a low removal efficiency of ultrafine particulates in the size range of 10-1000 nm, which are badly harmful to human health. Herein, a novel self-powered electrostatic adsorption face mask (SEA-FM) based on the poly(vinylidene fluoride) electrospun nanofiber film (PVDF-ESNF) and a triboelectric nanogenerator (TENG) driven by respiration (R-TENG) is developed. The ultrafine particulates are electrostatically adsorbed by the PVDF-ESNF, and the R-TENG can continually provide electrostatic charges in this adsorption process by respiration. On the basis of the R-TENG, the SEA-FM shows that the removal efficiency of coarse and fine particulates is higher than 99.2 wt % and the removal efficiency of ultrafine particulates is still as high as 86.9 wt % after continually wearing for 240 min and a 30-day interval. This work has proposed as a new method of wearable air filtration and may have great prospects in human health, self-powered electronics, and wearable devices.

Motion behavior of water droplets driven by triboelectric nanogenerator

By integrating a triboelectric nanogenerator (TENG) and a simple circuit board, the motion of water droplets can be controlled by the output of the TENG, which demonstrates a self-powered microfluidic system toward various practical applications in the fields of microfluidic system and soft robotics. This paper describes a method to construct a physical model for this self-powered system on the basis of electrostatic induction theory. The model can precisely simulate the detailed motion behavior of the droplet under driving of TENG, and it can also reveal the influences of surface hydrophobicity on the motion of the droplet, which can help us to better understand the key parameters that decide the performance of the system. The experimental observation of the dynamic performance of the droplet has also been done with a high speed camera system. A comparison between simulation results and real measurements confirms that the proposed model can predict the velocity and position of the water droplet driven by high voltage source as well as TENG. Hence, the proposed model in this work could serve as a guidance for optimizing the self-powered systems in future studies.By integrating a triboelectric nanogenerator (TENG) and a simple circuit board, the motion of water droplets can be controlled by the output of the TENG, which demonstrates a self-powered microfluidic system toward various practical applications in the fields of microfluidic system and soft robotics. This paper describes a method to construct a physical model for this self-powered system on the basis of electrostatic induction theory. The model can precisely simulate the detailed motion behavior of the droplet under driving of TENG, and it can also reveal the influences of surface hydrophobicity on the motion of the droplet, which can help us to better understand the key parameters that decide the performance of the system. The experimental observation of the dynamic performance of the droplet has also been done with a high speed camera system. A comparison between simulation results and real measurements confirms that the proposed model can predict the velocity and position of the water droplet driven by...

Infrared detector fabricated by YBCO Josephson junctions in series

Abstract The infrared detectors were fabricated by YBCO bicrystal and step-edge junctions in series. The detectors exhibited an high responsivity of 780 V/W at 77K and low NEP of 9.0 × 10 −13 W/√Hz. The optical response of the detectors below T c is mainly of nonequilibrium origin.

Sensitive dc-SQUIDs and magnetometers using step-edge junctions

Abstract Superconducting quantum interference devices (SQUIDS) using YBa 2 Cu 3 O 7 step-edge grain boundary junctions on LaAlO 3 substrates were fabricated. The I–V and V -φ characteristics of these step-junction dc-SQUIDs were studied. At 77K, a square washer configuration with inductance L s =150 pH yields flux noise of about 5.08×10 −5 φ 0 √Hz, corresponding to a magnetic field and energy resolutions were 270 ft/√Hz and 3.68×10 −29 J/Hz respectively above 100 Hz.

High-Tc SQUID series arrays using step edge junctions

Abstract We have successfully fabricated some superconducting quantum interference device (SQUID) series arrays using step-edge junctions. The operation of a SQUID array with 10 dc-SQUIDs has been demonstrated using a single flux-locked loop. At 77 K, the SQUID array had a flux noise of about 1.80 × 10 −4 φ 0 /√Hz at frequencies above 100 Hz. Our results show that a SQUID array can have a significant impact on those applications that demand good noise performance.

Growth and characterization of a-axis oriented YBa2Cu3O7-x thin films on SrTiO3 substrates

Abstract Using Self-template process, Superconducting a-axis oriented thin films of YBa 2 Cu 3 O 7−x (YBCO) were prepared on SrTiO 3 (STO) (100) substrates by dc magnetron sputtering in the on-axis configuration. X-ray diffraction (XRD) and transmission electron microscopy (TEM) analyses show that the growth of YBCO thin films were perpendicular to surface of substrate. The YBCO thin films of a-axis oriented have a zero resistance temperature(Tc 0 ) of 85K and transition width of about 2K. Anisotropy ratio of resistivity and effect of template layer on the quality of the films were investigated.

Enhancement of superconductivity by low energy Ar ion milling in epitaxial YBa2Cu3O7 thin films

Abstract Epitaxial YBa 2 Cu 3 O 7 thin films were etched with low energy Ar ion at room temperature. It was found that, a substantial enhancement of the superconducting transition temperature was obtained at a short time milling for both electrical and magnetic measurement. The X-ray diffraction showed that the lattice frame of the sample was nearly unchanged after lower energy Ar ion milling. We suggest that the T c enhancement may be caused by the oxygen redistribution at low energy Ar ion milling.