Publications by authors named "Hua-Yang Li"

16 Publications

  • Page 1 of 1

A Flexible and Ultra-Highly Sensitive Tactile Sensor through a Parallel Circuit by a Magnetic Aligned Conductive Composite.

ACS Nano 2022 Jan 5. Epub 2022 Jan 5.

CAS Center for Excellence in Nanoscience, Beijing Key Laboratory of Micro-Nano Energy and Sensor, Beijing Institute of Nanoenergy and Nanosystems, Chinese Academy of Sciences, Beijing 100083, People's Republic of China.

The development of flexible electronic skins with high performance and multifunctional sensing capabilities is of great significance for applications ranging from healthcare monitoring to artificial intelligence. To mimic and surpass the high-gauge-factor sensing properties of human skin, structure design and appropriate material selection of sensors are both essentially required. Here, we present an efficient, low-cost fabrication strategy to construct an ultra-highly sensitive, flexible pressure sensor by embedding the aligned nickel-coated carbon fibers (NICFs) in a polydimethylsiloxane (PDMS) substrate. Our design substantially contributes to ultrahigh sensitivity through the parallel circuit formed by aligned NICFs as well as surface spinosum microstructure molded by sandpaper. As a result, the sensor exhibits excellent sensitivity (15 525 kPa), a fast response time (30 ms), and good stability over 3000 loading-unloading cycles. Furthermore, these superior sensing properties trigger applications in water quality and wave monitoring in conjunction with mechanical flexibility and robustness. As a precedent for adjusting the sensitivities of the sensor, the NICFs/PDMS sensor provides a promising method for multiscenario healthcare monitoring, multiscale pressure spatial distribution, and human-machine interfacing.
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http://dx.doi.org/10.1021/acsnano.1c08273DOI Listing
January 2022

Facile Fabrication of Flexible Pressure Sensor with Programmable Lattice Structure.

ACS Appl Mater Interfaces 2021 Mar 19;13(8):10388-10396. Epub 2021 Feb 19.

New Materials Institute, Department of Mechanical, Materials and Manufacturing Engineering, University of Nottingham Ningbo China, Ningbo 315100, China.

Flexible pressure sensors have attracted intense attention because of their widespread applications in electronic skin, human-machine interfaces, and healthcare monitoring. Conductive porous structures are always utilized as active layers to improve the sensor sensitivities. However, flexible pressure sensors derived from traditional foaming techniques have limited structure designability. Besides, random pore distribution causes difference in structure and signal repeatability between different samples even in one batch, therefore limiting the batch production capabilities. Herein, we introduce a structure designable lattice structure pressure sensor (LPS) produced by bottom-up digital light processing (DLP) 3D printing technique, which is capable of efficiently producing 55 high fidelity lattice structure models in 30 min. The LPS shows high sensitivity (1.02 kPa) with superior linearity over a wide pressure range (0.7 Pa to 160 kPa). By adjusting the design parameters such as lattice type and layer thickness, the electrical sensitivities and mechanical properties of LPS can be accurately controlled. In addition, the LPS endures up to 60000 compression cycles (at 10 kPa) without any obvious electrical signal degradation. This benefits from the firm carbon nanotubes (CNTs) coating derived from high-energy ultrasonic probe and the subsequent thermal curing process of UV-heat dual-curing photocurable resin. For practical applications, the LPS is used for real time pulse monitoring, voice recognition and Morse code communication. Furthermore, the LPS is also integrated to make a flexible 4 × 4 sensor arrays for detecting spatial pressure distribution and a flexible insole for foot pressure monitoring.
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http://dx.doi.org/10.1021/acsami.0c21407DOI Listing
March 2021

Highly conductive, stretchable, and breathable epidermal electrode based on hierarchically interactive nano-network.

Nanoscale 2020 Aug;12(30):16053-16062

CAS Center for Excellence in Nanoscience, Beijing Key Laboratory of Micro-Nano Energy and Sensor, Beijing Institute of Nanoenergy and Nanosystems, Chinese Academy of Sciences, Beijing 100083, China. and School of Nanoscience and Technology, University of Chinese Academy of Sciences, Beijing 100049, China and New Materials Institute, Department of Mechanical, Materials and Manufacturing Engineering, University of Nottingham Ningbo China, Ningbo 315100, China.

Stretchable electrodes have a crucial impact on the development of flexible electronic systems. Most conventionally blended nanocomposite electrodes are incapable of achieving high stretchability, breathability, or durability. In this work, a highly conductive, breathable, and stretchable epidermal electrode (SEE) is demonstrated by designing a hierarchically interactive nano-network that is composed of elastic polymer nano-fibers and multi-level silver nano-wires (AgNWs). The elastic polymer nano-fibers act as a continuous scaffold, and multi-level AgNWs embedded in the nano-fibers form branched conductive pathways. This structure enables high conductivity of the SEE at 4800 S cm-1 (at a significantly low AgNW content of 1.59 vt%), with high stretchability and excellent durability. For example, the SEE remained conductive even at a high strain of 500%, and it also maintained its initial resistance even after 30 000 cycles of strain at 50% or being washed with water for 100 000 cycles. The SEE was prepared by a facile in situ nonequilibrium fabrication process, and can easily be produced into an elastic circuit on a large scale, which provides a foundation for integrated and multifunctional electronic skins. The SEE possesses superior mechanical conformability and permeability of gas and liquid, and therefore, it was successfully applied in measuring electrocardiogram signals and thermal therapy, and exhibited highly robust and comfortable performances even while being washed with water or undergoing complex deformations.
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http://dx.doi.org/10.1039/d0nr03189eDOI Listing
August 2020

Ultracomfortable Hierarchical Nanonetwork for Highly Sensitive Pressure Sensor.

ACS Nano 2020 08 3;14(8):9605-9612. Epub 2020 Aug 3.

CAS Center for Excellence in Nanoscience, Beijing Key Laboratory of Micro-Nano Energy and Sensor, Beijing Institute of Nanoenergy and Nanosystems, Chinese Academy of Sciences, Beijing 100083, China.

Skin sensors are of paramount importance for flexible wearable electronics, which are active in medical diagnosis and healthcare monitoring. Ultrahigh sensitivity, large measuring range, and high skin conformability are highly desirable for skin sensors. Here, an ultrathin flexible piezoresistive sensor with high sensitivity and wide detection range is reported based on hierarchical nanonetwork structured pressure-sensitive material and nanonetwork electrodes. The hierarchical nanonetwork material is composed of silver nanowires (Ag NWs), graphene (GR), and polyamide nanofibers (PANFs). Among them, Ag NWs are evenly interspersed in a PANFs network, forming conductive pathways. Also, GR acts as bridges of crossed Ag NWs. The hierarchical nanonetwork structure and GR bridges of the pressure-sensitive material enable the ultrahigh sensitivity for the pressure sensor. More specifically, the sensitivity of 134 kPa (0-1.5 kPa) and the low detection of 3.7 Pa are achieved for the pressure sensor. Besides, the nanofibers act as a backbone, which provides effective protection for Ag NWs and GR as pressure is applied. Hence, the pressure sensor possesses an excellent durability (>8000 cycles) and wide detection range (>75 kPa). Additionally, ultrathin property (7 μm) and nanonetwork structure provide high skin conformability for the pressure sensor. These superior performances lay a foundation for the application of pressure sensors in physiological signal monitoring and pressure spatial distribution detection.
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http://dx.doi.org/10.1021/acsnano.9b10230DOI Listing
August 2020

Large-Area Integrated Triboelectric Sensor Array for Wireless Static and Dynamic Pressure Detection and Mapping.

Small 2020 01 9;16(2):e1906352. Epub 2019 Dec 9.

CAS Center for Excellence in Nanoscience, Beijing Key Laboratory of Micro-Nano Energy and Sensor, Beijing Institute of Nanoenergy and Nanosystems, Chinese Academy of Sciences, Beijing, 100083, P. R. China.

Large-area flexible pressure sensors are of paramount importance for various future applications, such as electronic skin, human-machine interfacing, and health-monitoring devices. Here, a self-powered and large-area integrated triboelectric sensor array (ITSA) based on coupling a triboelectric sensor array and an array chip of CD4066 through a traditional connection is reported. Enabled by a simple and cost-effective fabrication process, the size of the ITSA can be scaled up to 38 × 38 cm . In addition, unlike previously proposed triboelectric sensors arrays, which can only react to the dynamic interaction, this ITSA is able to detect static and dynamic pressure. Moreover, through integrating the ITSA with a signal processing circuit, a complete wireless sensing system is present. Diverse applications of the system are demonstrated in detail, including detecting pressure, identifying position, tracking trajectory, and recognizing the profile of external contact objects. Thus, the ITSA in this work opens a new route in the direction of large-area, self-powered, and wireless triboelectric sensing systems.
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http://dx.doi.org/10.1002/smll.201906352DOI Listing
January 2020

Small-Sized, Lightweight, and Flexible Triboelectric Nanogenerator Enhanced by PTFE/PDMS Nanocomposite Electret.

ACS Appl Mater Interfaces 2019 Jun 22;11(22):20370-20377. Epub 2019 May 22.

CAS Center for Excellence in Nanoscience, Beijing Key Laboratory of Micro-Nano Energy and Sensor , Beijing Institute of Nanoenergy and Nanosystems, Chinese Academy of Sciences , Beijing 100083 , China.

The rapid development of flexible and wearable electronics calls for a sustainable solution of the power supply. In recent years, the energy-harvesting triboelectric nanogenerator (TENG) has attracted increasing attentions due to its sustainability, flexibility, and versatility. However, achieving both high electric output and flexibility at the same time remains to be a challenge. In this work, we reported a corona charging enhanced flexible triboelectric nanogenerator (EF-TENG) to harvest mechanical energy from human motions. The EF-TENG relied on the repeated contacts between a poly(tetrafluoroethylene)/poly(dimethylsiloxane) nanocomposite electret and a nanofibers/AgNWs electrode on arrayed silicone pyramids. When the EF-TENG (3.5 × 3.5 cm) was pressed, the open-circuit voltage ( V), the short-circuit current ( I), and the power density could reach 275 V, 9.5 μA, and 802.31 mW/m, respectively. The V of the EF-TENG was improved by 244% compared to the device of which the electret was not corona charged. Major factors that affected the electric output of the EF-TENG were discussed, including the height of the pyramids, the configuration of the pyramids array, and the properties of the electret nanocomposite. The EF-TENG only had an overall thickness of 1.3 mm and a weight of 1.7 g, making it especially suitable to be attached onto human body for harvesting mechanical energy from biomechanical motions.
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http://dx.doi.org/10.1021/acsami.9b04321DOI Listing
June 2019

Nanofiber-Reinforced Silver Nanowires Network as a Robust, Ultrathin, and Conformable Epidermal Electrode for Ambulatory Monitoring of Physiological Signals.

Small 2019 05 25;15(22):e1900755. Epub 2019 Apr 25.

CAS Center for Excellence in Nanoscience, Beijing Key Laboratory of Micro-Nano Energy and Sensor, Beijing Institute of Nanoenergy and Nanosystems, Chinese Academy of Sciences, Beijing, 100083, China.

Extremely soft and thin electrodes with high skin conformability have potential applications in wearable devices for personal healthcare. Here, a submicrometer thick, highly robust, and conformable nanonetwork epidermal electrode (NEE) is reported. Electrospinning of polyamide nanofibers and electrospraying of silver nanowires are simultaneously performed to form a homogeneously convoluted network in a nonwoven way. For a 125 nm thick NEE, a low sheet resistance of ≈4 Ω sq with an optical transmittance of ≈82% is achieved. Due to the nanofiber-based scaffold that undertakes most of the stress during deformation, the electric resistance of the NEE shows very little variation; less than 1.2% after 50 000 bending cycles. The NEE can form a fully conformal contact to human skin without additional adhesives, and the NEE shows a contact impedance that is over 50% lower than what is found in commercial gel electrodes. Due to conformal contact even under deformation, the NEE proves to be a stable, robust, and comfortable approach for measuring electrocardiogram signals, especially when a subject is in motion. These features make the NEE promising for use in the ambulatory measurement of physiological signals for healthcare applications.
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http://dx.doi.org/10.1002/smll.201900755DOI Listing
May 2019

Enhanced High-Resolution Triboelectrification-Induced Electroluminescence for Self-Powered Visualized Interactive Sensing.

ACS Appl Mater Interfaces 2019 Apr 28;11(14):13796-13802. Epub 2019 Mar 28.

CAS Center for Excellence in Nanoscience, Beijing Key Laboratory of Micro-Nano Energy and Sensor, Beijing Institute of Nanoenergy and Nanosystems , Chinese Academy of Sciences , Beijing 100083 , China.

Transforming dynamic mechanical interactions into visualized luminescence represents a research frontier in the detection of tactile stimuli. Here, we report a self-powered high-resolution triboelectrification-induced electroluminescence (HR-TIEL) sensor for visualizing the contact profile and dynamic trajectory of a contact object. As dynamic interactions occur, triboelectric charges at the contact interface generate a transient electric field that excites the phosphor. From the numerical simulation, a conductive layer based on transparent silver nanowires (AgNWs) guides the direction of the electric field and confines it within the profile boundary of the connect object. As a result, a sharp change of the electric field at the profile boundary greatly promotes the luminescence intensity as well as the lateral spatial resolution. Compared to a triboelectrification-induced electroluminescence (TIEL) sensor without the conductive layer, the luminescence intensity is enhanced by 90%, and the lateral spatial resolution of ∼500 μm is achieved. The HR-TIEL sensor is then demonstrated to reveal the surface texture on a nitrile glove. It relies on neither additional power supplies nor complex wiring/circuit design. This work paves the way for the feasible detection of tactile stimuli such as touch and slipping, which will be potentially used in robotics, human-machine interface, flexible and wearable electronics, and so forth.
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http://dx.doi.org/10.1021/acsami.9b02313DOI Listing
April 2019

Dehydroepiandrosterone attenuates pulmonary artery and right ventricular remodeling in a rat model of pulmonary hypertension due to left heart failure.

Life Sci 2019 Feb 31;219:82-89. Epub 2018 Dec 31.

Cardiovascular Department of the Sixth Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong Province, China. Electronic address:

Aim: Pulmonary hypertension due to left heart failure (PH-LHF) is the most common cause of pulmonary hypertension. However, therapies for PH-LHF are lacking. Therefore, we investigated the effects and potential mechanism of dehydroepiandrosterone (DHEA) treatment in an experimental model of PH-LHF.

Main Method: PH-LHF was induced in rats via ascending aortic banding. The rats then received daily DHEA from Day 1 to Day 63 for the prevention protocol or from Day 49 to Day 63 for the reversal protocol. Other ascending aortic banding rats were left untreated to allow development of PH and right ventricular (RV) failure. Sham ascending aortic banding rats served as controls.

Key Finding: Significant increases in mean pulmonary arterial pressure (mPAP) and right ventricular end-diastolic diameter (RVEDD) were observed in the PH-LHF group. Therapy with DHEA prevented LHF-induced PH and RV failure by preserving mPAP and preventing RV hypertrophy and pulmonary artery remodeling. In preexisting severe PH, DHEA attenuated most lung and RV abnormalities. The beneficial effects of DHEA in PH-LHF seem to result from depression of the STAT3 signaling pathway in the lung.

Significant: DHEA not only prevents the development of PH-LHF and RV failure but also rescues severe preexisting PH-LHF.
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http://dx.doi.org/10.1016/j.lfs.2018.12.056DOI Listing
February 2019

Flexible Porous Polydimethylsiloxane/Lead Zirconate Titanate-Based Nanogenerator Enabled by the Dual Effect of Ferroelectricity and Piezoelectricity.

ACS Appl Mater Interfaces 2018 Oct 24;10(39):33105-33111. Epub 2018 Sep 24.

CAS Center for Excellence in Nanoscience, Beijing Key Laboratory of Micro-nano Energy and Sensor, Beijing Institute of Nanoenergy and Nanosystems , Chinese Academy of Sciences , Beijing 100083 , China.

Flexible piezoelectric nanogenerators have drawn considerable attention for their wide applications in harvesting ambient mechanical energy. Here, we report a flexible porous nanogenerator (FPNG) based on the dual effect of ferroelectricity and piezoelectricity. The electric output originated from the combination of the above two effects can be constructively added up, resulting in an enhancement of the electric output. With dimensions of 2 × 2 × 0.3 cm, the FPNG can generate an open-circuit voltage ( V) of 29 V and a short-circuit current ( I) of 116 nA under a compressive force of 30 N. Besides, the FPNG is applicable to other forms of mechanical stimuli, including twisting and bending. Harvesting energy from a rowing bicycle tire is demonstrated in this report. This work provides a new route to promoting the electric output of piezoelectric nanogenerators.
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http://dx.doi.org/10.1021/acsami.8b06696DOI Listing
October 2018

Triboelectrification-Induced Self-Assembly of Macro-Sized Polymer Beads on a Nanostructured Surface for Self-Powered Patterning.

ACS Nano 2018 01 10;12(1):441-447. Epub 2018 Jan 10.

CAS Center for Excellence in Nanoscience, Beijing Institute of Nanoenergy and Nanosystems, Chinese Academy of Sciences , Beijing 100083, China.

Here we report an electrostatic-templated self-assembly (ETSA) method for arbitrarily patterning millimeter-sized polymer beads on a nanostructured surface without using an extra voltage source. A patterned electrode underneath an electrification layer generates "potential wells" of the corresponding pattern at predefined window sites, which capture and anchor the beads within the window sites by electrostatic force. Analytical calculation is combined with numerical modeling to derive the electrostatic force acting on the beads, which is in great agreement with experimentally measured values. The generated pattern is solely determined by the predefined underlying electrode, making it arbitrarily switchable by using different electrode patterns. By transferring the assembled beads into an elastomer matrix, possible applications of the ETSA in fabricating optical and flexible displays are demonstrated.
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http://dx.doi.org/10.1021/acsnano.7b06758DOI Listing
January 2018

Stretchable Porous Carbon Nanotube-Elastomer Hybrid Nanocomposite for Harvesting Mechanical Energy.

Adv Mater 2017 Jan 21;29(2). Epub 2016 Nov 21.

Beijing Institute of Nanoenergy and Nanosystems, Chinese Academy of Sciences, National Center for Nanoscience and Technology (NCNST), Beijing, 100083, P. R. China.

A stretchable porous nanocomposite (PNC) is reported based on a hybrid of a multiwalled carbon nanotubes network and a poly(dimethylsiloxane) matrix for harvesting energy from mechanical interactions. The deformation-enabled energy-generating process makes the PNC applicable to various mechanical interactions, including pressing, stretching, bending, and twisting. It can be potentially used as an energy solution for wearable electronics.
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http://dx.doi.org/10.1002/adma.201603115DOI Listing
January 2017

Dynamic Triboelectrification-Induced Electroluminescence and its Use in Visualized Sensing.

Adv Mater 2016 Aug 23;28(31):6656-64. Epub 2016 May 23.

Beijing Institute of Nanoenergy and Nanosystems, Chinese Academy of Sciences, National Center for Nanoscience and Technology (NCNST), Beijing, 100083, P. R. China.

Triboelectrification-induced electroluminescence converts dynamic motion into light emission. Tribocharges resulting from the relative mechanical interactions between two dissimilar materials can abruptly and significantly alter the surrounding electric potential, exciting the electroluminescence of phosphor along the motion trajectory. The position, trajectory, and contour profile of a moving object can be visualized in high resolution, demonstrating applications in sensing.
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http://dx.doi.org/10.1002/adma.201600604DOI Listing
August 2016

High-Performance Organolead Halide Perovskite-Based Self-Powered Triboelectric Photodetector.

ACS Nano 2015 Nov 27;9(11):11310-6. Epub 2015 Oct 27.

Beijing Institute of Nanoenergy and Nanosystems, Chinese Academy of Sciences , Beijing 100083, China.

We report a MAPbI3-based self-powered photodetector (SPPD). It has a dual sensing mechanism that relies on the joint properties of a photoelectric effect and a triboelectric effect of the perovskite material. Both the photoconductivity and the surface triboelectric density of the MAPbI3-based composite thin film are significantly altered upon solar illumination, which results in considerable reduction of the output voltage. The SPPD exhibits excellent responsivity (7.5 V W(-1)), rapid response time (<80 ms), great repeatability, and broad detection range that extends from UV to visible regions. This work presents a route to designing high-performance self-powered photodetectors from the aspect of materials.
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http://dx.doi.org/10.1021/acsnano.5b04995DOI Listing
November 2015

Interface-Free Area-Scalable Self-Powered Electroluminescent System Driven by Triboelectric Generator.

Sci Rep 2015 Sep 4;5:13658. Epub 2015 Sep 4.

Beijing Institute of Nanoenergy and Nanosystems, Chinese Academy of Sciences, Beijing, 100083, China.

Self-powered system that is interface-free is greatly desired for area-scalable application. Here we report a self-powered electroluminescent system that consists of a triboelectric generator (TEG) and a thin-film electroluminescent (TFEL) lamp. The TEG provides high-voltage alternating electric output, which fits in well with the needs of the TFEL lamp. Induced charges pumped onto the lamp by the TEG generate an electric field that is sufficient to excite luminescence without an electrical interface circuit. Through rational serial connection of multiple TFEL lamps, effective and area-scalable luminescence is realized. It is demonstrated that multiple types of TEGs are applicable to the self-powered system, indicating that the system can make use of diverse mechanical sources and thus has potentially broad applications in illumination, display, entertainment, indication, surveillance and many others.
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http://dx.doi.org/10.1038/srep13658DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4559893PMC
September 2015

Triboelectric Charging at the Nanostructured Solid/Liquid Interface for Area-Scalable Wave Energy Conversion and Its Use in Corrosion Protection.

ACS Nano 2015 Jul 17;9(7):7671-7. Epub 2015 Jul 17.

†Beijing Institute of Nanoenergy and Nanosystems, Chinese Academy of Sciences, Beijing 100083, China.

We report a flexible and area-scalable energy-harvesting technique for converting kinetic wave energy. Triboelectrification as a result of direct interaction between a dynamic wave and a large-area nanostructured solid surface produces an induced current among an array of electrodes. An integration method ensures that the induced current between any pair of electrodes can be constructively added up, which enables significant enhancement in output power and realizes area-scalable integration of electrode arrays. Internal and external factors that affect the electric output are comprehensively discussed. The produced electricity not only drives small electronics but also achieves effective impressed current cathodic protection. This type of thin-film-based device is a potentially practical solution of on-site sustained power supply at either coastal or off-shore sites wherever a dynamic wave is available. Potential applications include corrosion protection, pollution degradation, water desalination, and wireless sensing for marine surveillance.
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http://dx.doi.org/10.1021/acsnano.5b03093DOI Listing
July 2015
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