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1.
Nano Energy ; : 104910, 2020 May 04.
Artigo em Inglês | MEDLINE | ID: mdl-32373446

RESUMO

Due to the natural characteristics of high voltage output, Triboelectric nanogenerators (TENGs) have huge advantages in many fields. Here, we have proposed a concept of Mobile ultraviolet light sources (Mobile-UV) driven by TENG, without any additional circuits. For this system, analysis of electric characteristics, optical emission spectra, and COMSOL simulation were carried out to promote the performance. Subsequently, we have developed exploratory applications in the fields of bio-sterilization, chemical detection, and UV-curing, which proved the versatility and effectiveness. This work offers a promising, portable, effective, and safe supplement to traditional ultraviolet light sources, and will enrich the diversity of the ultraviolet application based on the reach of existing technologies.

2.
Artigo em Inglês | MEDLINE | ID: mdl-32394517

RESUMO

The ability to deliberately solution-print large-scale perovskite-based nanostructures represents a significant endeavor towards the convenient creation of a rich variety of optoelectronic materials and devices. Despite recent impressive progress in producing perovskite nanowires (NWs) for optoelectronics, it remains challenging to solution-print an array of NWs with precisely controlled position and orientation. Herein, we report a robust capillary-assisted solution printing (CASP) strategy to rapidly access aligned and highly crystalline perovskite NWs array. The key to the CASP approach lies in the judicious integration of capillary-directed assembly via periodic nanochannels and solution printing via the programmably-moved substrate to fast guide the deposition of perovskite NWs. The growth kinetics of perovskite NWs is closely examined by in-situ optical microscopy to scrutinize the perovskite crystallization. Intriguingly, as-printed perovskite NWs array exhibit excellent optical and optoelectronic properties, and can be conveniently implemented for scalable fabrication of photodetectors.

3.
ACS Nano ; 2020 May 11.
Artigo em Inglês | MEDLINE | ID: mdl-32369343

RESUMO

The integration between energy-harvesting and energy-storage devices into a self-charging power unit is an effective approach to address the energy bottleneck of wearable/portable/wireless smart devices. Herein, we demonstrate a stretchable coplanar self-charging power textile (SCPT) with triboelectric nanogenerators (TENGs) and microsupercapacitors (MSCs) both fabricated through a resist-dyeing-analogous method. The textile electrodes maintain excellent conductivity at 600% and 200% tensile strain along course and wale directions, respectively. The fabric in-plane MSC with reduced graphene oxides as active materials reaches a maximum areal capacitance of 50.6 mF cm-2 at 0.01 V s-1 and shows no significant degradation at 50% of tensile strain. The stretchable fabric-based TENG can output 49 V open-circuit voltage and 94.5 mW m-2 peak power density. Finally, a stretchable coplanar SCPT with one-batch resist-dyeing fabrication is demonstrated for powering small electronics intermittently without extra recharging. Our approach is also compatible with conventional textile processing and suggests great potential in electronic textiles and wearable electronics.

4.
Adv Mater ; : e2001307, 2020 May 14.
Artigo em Inglês | MEDLINE | ID: mdl-32410246

RESUMO

Polymers are commonly used to fabricate triboelectric nanogenerators (TENGs). Here, several polymer films with similar main chains but different functional groups on the side chain are employed to clarify the contributions of each functional group to contact electrification (CE). The results show that the electron-withdrawing (EW) ability and density of these functional groups on the main chain can determine both the polarity and density of CE-induced surface charges. Similar results are obtained for CE in both the polymer-polymer and polymer-liquid modes. A theoretical mechanism involving electron cloud overlap is proposed to explain all of these results. More importantly, the unsaturated groups on poly(tetrafluoroethylene) molecular chain are proved to have a much stronger EW ability than the saturated groups. The density of these unsaturated groups can be increased using a sputtering technique, suggesting that this is a facile and effective method of enhancing the performance of TENGs. These results clarify the correlation between the molecular structure and macroscopic electrification behavior of polymers.

5.
ACS Nano ; 2020 Apr 23.
Artigo em Inglês | MEDLINE | ID: mdl-32315160

RESUMO

In recent years, the triboelectric nanogenerator (TENG) has attracted increasing attention because it not only converts various mechanical energy into electrical energy but also produces electrical signals as responses. On the basis of the TENG, a magnetic flap type difunctional sensor (MFTDS) has been developed to detect pneumatic flow and liquid level. Consisting of an outer magnetic flap, an inner magnetic float, and a conical cavity, its working mechanism and output characteristics were studied. The MFTDS detects pneumatic flows from 10 to 200 L/min with a flow resolution of 2 L/min. Compared with a commercial flow switch, the MFTDS results are in good agreement. Moreover, the MFTDS detects changes in liquid levels. The effects of liquid level height and flow rate on the performance of the MFTDS were measured and compared with a commercial liquid-level sensor. The results indicate that the output voltage of the MFTDS varies linearly with height but is independent of flow rate. The heights of liquid level from 30 to 130 mm were effectively detected. This work promotes the prospect for multifunctional triboelectric sensors.

6.
Adv Mater ; : e1908445, 2020 Apr 20.
Artigo em Inglês | MEDLINE | ID: mdl-32310315

RESUMO

Commercial lithium-ion batteries (LIBs), limited by their insufficient reversible capacity, short cyclability, and high cost, are facing ever-growing requirements for further increases in power capability, energy density, lifespan, and flexibility. The presence of insulating and electrochemically inactive binders in commercial LIB electrodes causes uneven active material distribution and poor contact of these materials with substrates, reducing battery performance. Thus, nanostructured electrodes with binder-free designs are developed and have numerous advantages including large surface area, robust adhesion to substrates, high areal/specific capacity, fast electron/ion transfer, and free space for alleviating volume expansion, leading to superior battery performance. Herein, recent progress on different kinds of supporting matrixes including metals, carbonaceous materials, and polymers as well as other substrates for binder-free nanostructured electrodes in LIBs are summarized systematically. Furthermore, the potential applications of these binder-free nanostructured electrodes in practical full-cell-configuration LIBs, in particular fully flexible/stretchable LIBs, are outlined in detail. Finally, the future opportunities and challenges for such full-cell LIBs based on binder-free nanostructured electrodes are discussed.

7.
Adv Mater ; : e2000928, 2020 Apr 09.
Artigo em Inglês | MEDLINE | ID: mdl-32270901

RESUMO

Contact electrification (CE or triboelectrification) is a common phenomenon, which can occur for almost all types of materials. In previous studies, the CE between insulators and metals has been widely discussed, while CE involving semiconductors is only recently. Here, a tribo-current is generated by sliding an N-type diamond coated tip on a P-type or N-type Si wafers. The density of surface states of the Si wafer is changed by introducing different densities of doping. It is found that the tribo-current between two sliding semiconductors increases with increasing density of surface states of the semiconductor and the sliding load. The results suggest that the tribo-current is induced by the tribovoltaic effect, in which the electron-hole pairs at the sliding interface are excited by the energy release during friction, which may be due to the transition of electrons between the surface states during contact, or bond formation across the sliding interface. The electron-hole pairs at the sliding interface are subsequently separated by the built-in electric field at the PN or NN heterojunctions, which results in a tribo-current, in analogy to that which occurs in the photovoltaic effect.

8.
Small ; : e1907603, 2020 Apr 09.
Artigo em Inglês | MEDLINE | ID: mdl-32270918

RESUMO

Current photocatalytic semiconductors often have low catalytic performance due to limited light utilization and fast charge carrier recombination. Formation of Schottky junction between semiconductors and plasmonic metals can broaden the light absorption and facilitate the photon-generated carriers separation. To further amplify the catalytic performance, herein, an asymmetric gold-zinc oxide (Asy-Au-ZnO) nanorod array is rationally designed, which realizes the synergy of piezocatalysis and photocatalysis, as well as spatially oriented electron-hole pairs separation, generating a significantly enhanced catalytic performance. In addition to conventional properties from noble metal/semiconductor Schottky junction, the rationally designed heterostructure has several additional advantages: 1) The piezoelectric ZnO under light and mechanical stress can directly generate charge carriers; 2) the Schottky barrier can be reduced by ZnO piezopotential to enhance the injection efficiency of hot electrons from Au nanoparticles to ZnO; 3) the unique asymmetric nanorod array structure can achieve a spatially directed separation and migration of the photon-generated carriers. When ultrasound and all-spectrum light irradiation are exerted simultaneously, the Asy-Au-ZnO reaches the highest catalytic efficiency of 95% in 75 min for dye degradation. It paves a new pathway for designing unique asymmetric nanostructures with the synergy of photocatalysis and piezocatalysis.

9.
Nano Lett ; 20(5): 3761-3768, 2020 May 13.
Artigo em Inglês | MEDLINE | ID: mdl-32329622

RESUMO

Tactile information is efficiently captured and processed through a complex sensory system combined with mechanoreceptors, neurons, and synapses in human skin. Synapses are essential for tactile signal transmission between pre/post-neurons. However, developing an electronic device that integrates the functions of tactile information sensation and transmission remains a challenge. Here, we present a piezotronic synapse based on a single GaN microwire that can simultaneously achieve the capabilities of strain sensing and synaptic functions. The piezotronic effect in the wurtzite GaN is introduced to strengthen synaptic weight updates (e.g., 330% enhancement at a compressive stress of -0.36%) with pulse trains. A high gauge factor for strain sensing (ranging from 0 to -0.81%) of about 736 is also obtained. Remarkably, the piezotronic synapse enables the neuromorphic hardware achievement of the perception and processing of tactile information in a single micro/nanowire system, demonstrating an advance in biorealistic artificial intelligence systems.

10.
ACS Nano ; 14(4): 4716-4726, 2020 Apr 28.
Artigo em Inglês | MEDLINE | ID: mdl-32255615

RESUMO

Textile-based triboelectric nanogenerators (TENG) that can effectively harvest biomechanical energy and sense multifunctional posture and movement have a wide range of applications in next-generation wearable and portable electronic devices. Hence, bulk production of fine yarns with high triboelectric output through a continuous manufacturing process is an urgent task. Here, an ultralight single-electrode triboelectric yarn (SETY) with helical hybridized nano-micro core-shell fiber bundles is fabricated by a facile and continuous electrospinning technology. The obtained SETY device exhibits ultralightness (0.33 mg cm-1), extra softness, and smaller size (350.66 µm in diameter) compared to those fabricated by conventional fabrication techniques. Based on such a textile-based TENG, high energy-harvesting performance (40.8 V, 0.705 µA cm-2, and 9.513 nC cm-2) was achieved by applying a 2.5 Hz mechanical drive of 5 N. Importantly, the triboelectric yarns can identify textile materials according to their different electron affinity energies. In addition, the triboelectric yarns are compatible with traditional textile technology and can be woven into a high-density plain fabric for harvesting biomechanical energy and are also competent for monitoring tiny signals from humans or insects.

11.
Sci Adv ; 6(11): eaay2840, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-32201720

RESUMO

Wearable textile electronics are highly desirable for realizing personalized health management. However, most reported textile electronics can either periodically target a single physiological signal or miss the explicit details of the signals, leading to a partial health assessment. Furthermore, textiles with excellent property and comfort still remain a challenge. Here, we report a triboelectric all-textile sensor array with high pressure sensitivity and comfort. It exhibits the pressure sensitivity (7.84 mV Pa-1), fast response time (20 ms), stability (>100,000 cycles), wide working frequency bandwidth (up to 20 Hz), and machine washability (>40 washes). The fabricated TATSAs were stitched into different parts of clothes to monitor the arterial pulse waves and respiratory signals simultaneously. We further developed a health monitoring system for long-term and noninvasive assessment of cardiovascular disease and sleep apnea syndrome, which exhibits great advancement for quantitative analysis of some chronic diseases.

12.
ACS Nano ; 2020 Mar 20.
Artigo em Inglês | MEDLINE | ID: mdl-32181639

RESUMO

Triboelectric nanogenerators (TENGs) have demonstrated their promising potential in biomotion energy harvesting. A combination of the TENG and textile materials presents an effective approach toward smart fabric. However, most traditional fabric TENGs with an alternating current (AC) have to use a stiff, uncomfortable, and unfriendly rectifier bridge to obtain direct current (DC) to store and supply power for electronic devices. Here, a DC fabric TENG (DC F-TENG) with the most common plain structure is designed to harvest biomotion energy by tactfully taking advantage of the harmful and annoying electrostatic breakdown phenomenon of clothes. A small DC F-TENG (1.5 cm × 3.5 cm) can easily light up 416 serially connected light-emitting diodes. Furthermore, some yarn supercapacitors are fabricated and woven into the DC F-TENG to harvest and store energy and to power electronic devices, such as a hygrothermograph or a calculator, which shows great convenience and high efficiency in practice. This low-cost and efficient DC F-TENG which can directly generate DC energy without using the rectifier bridge by harvesting energy from unhealthy electrostatic breakdown has great potential as a lightweight, flexible, wearable, and comfortable energy-harvesting device in the future.

13.
ACS Nano ; 2020 Feb 18.
Artigo em Inglês | MEDLINE | ID: mdl-32049482

RESUMO

Vibrations in the environment are usually distributed over a wide frequency spectrum in multiple directions and a weaker amplitude, which makes most of the current vibrational energy collectors limited in practical environmental applications. Herein, a triboelectric-electromagnetic hybridized nanogenerator (TEHG) for low-frequency random microvibrational energy harvesting in all directions and a wide working bandwidth is fabricated. The output peak power of a triboelectric nanogenerator (TENG) up to 3.65 mW is realized (θ = 0.4 rad, f = 1 Hz). In addition, a real self-powered seawater splitting system and electrochemical cathodic protection system are fabricated, directly converting blue energy to hydrogen energy, and the ships can achieve self-protection against corrosion. Furthermore, relying on the linear relationship between the number of peaks and the amplitude of vibration, a highly sensitive self-powered vibration amplitude sensor system based on LabVIEW software is achieved, which can be used as an amplitude detection of bridges and earthquake monitoring, etc. This work is an important development for harvesting low-frequency random multiple direction microvibrational energy over a wide working bandwidth and the bright future of blue energy. In addition, it has been successfully applied to the power supply of portable electronic equipment, environmental monitors, and self-powered systems.

14.
ACS Nano ; 2020 Feb 20.
Artigo em Inglês | MEDLINE | ID: mdl-32058695

RESUMO

Developing sophisticated device architectures is of great significance to go beyond Moore's law with versatility toward human-machine interaction and artificial intelligence. Tribotronics/tribo-iontronics offer a direct way to controlling the transport properties of semiconductor devices by mechanical actions, which fundamentally relies on how to enhance the tribotronic gating effect through device engineering. Here, we propose a universal method to enhance the tribotronic properties through electric double layer (EDL) capacitive coupling. By preparing an ion gel layer on top of tribotronic graphene transistor, we demonstrate a dual-mode field effect transistor (i.e., a tribotronic transistor with capacitively coupled ion gel and an ion-gel-gated graphene transistor with a second tribotronic gate). The resulted tribotronic gating performances are greatly improved by twice for the on-state current and four times for the on/off ratio (the first mode). It can also be utilized as a multiparameter distance sensor with drain current increased by ∼600 µA and threshold voltage shifted by ∼0.8 V under a mechanical displacement of 0.25 mm (the second mode). The proposed methodology of EDL capacitive coupling offers a facile and efficient way to designing more sophisticated tribotronic devices with superior performance and multifunctional sensations.

15.
Nanotechnology ; 31(24): 242001, 2020 Feb 24.
Artigo em Inglês | MEDLINE | ID: mdl-32092711

RESUMO

With the fast development of the Internet of Things, the energy supply for electronics and sensors has become a critical challenge. The triboelectric nanogenerator (TENG), which can transfer mechanical energy from the surrounding environment into electricity, has been recognized as the most promising alternative technology to remedy the shortcomings of traditional battery technology. Environmental mechanical energy widely exists in activities in nature and these environmental energy sources can enable TENGs to achieve a clean and distributed energy network, which can finally benefit the innovation of various wireless devices. In this review, TENGs targeting different environmental energy sources have been systematically summarized and analyzed. Firstly, we give a brief introduction to the basic principle and working modes of the TENG. Then, TENGs targeting different energy sources, from blowing wind and raindrops to pounding waves, noise signalling, and so on, are summarized based on their design concept and output performance. In addition, combined with other energy technologies such as solar cells, electromagnetic generators, and piezoelectric nanogenerators, the application of hybrid nanogenerators is elaborated under different scenarios. Finally, the challenges, limitations, and future research trends of environmental energy collection are outlined.

16.
ACS Nano ; 2020 Feb 12.
Artigo em Inglês | MEDLINE | ID: mdl-32040919

RESUMO

Vibration sensor is very necessary for monitoring the structural health of constructions. However, it is still a major challenge to meet simultaneously real-time monitoring, continuous assessment, and early incident warning in a simple device without a complicated power and analysis system. Here, we report a self-powered vibration sensor system to achieve real-time and continuous detection of the vibration characteristics from a dual-mode triboelectric nanogenerator (AC/DC-TENG), which can produce either alternating current (AC) or direct current (DC) within different operation zones. Within the vibration-safe region, the AC/DC-TENG with AC output not only can continuously assess the vibration characteristics but also can power the signal transmission. More importantly, once the vibration amplitude crosses the danger threshold, the AC converts immediately to DC, meanwhile triggering the alarm system directly to accurately predict the danger of construction. Our self-powered vibration sensor system can serve as a facile tool for accurately monitoring the structural health of constructions.

17.
Nature ; 578(7795): 392-396, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-32025037

RESUMO

Extensive efforts have been made to harvest energy from water in the form of raindrops1-6, river and ocean waves7,8, tides9 and others10-17. However, achieving a high density of electrical power generation is challenging. Traditional hydraulic power generation mainly uses electromagnetic generators that are heavy, bulky, and become inefficient with low water supply. An alternative, the water-droplet/solid-based triboelectric nanogenerator, has so far generated peak power densities of less than one watt per square metre, owing to the limitations imposed by interfacial effects-as seen in characterizations of the charge generation and transfer that occur at solid-liquid1-4 or liquid-liquid5,18 interfaces. Here we develop a device to harvest energy from impinging water droplets by using an architecture that comprises a polytetrafluoroethylene film on an indium tin oxide substrate plus an aluminium electrode. We show that spreading of an impinged water droplet on the device bridges the originally disconnected components into a closed-loop electrical system, transforming the conventional interfacial effect into a bulk effect, and so enhancing the instantaneous power density by several orders of magnitude over equivalent devices that are limited by interfacial effects.

18.
ACS Nano ; 2020 Feb 14.
Artigo em Inglês | MEDLINE | ID: mdl-32057223

RESUMO

As one of the major air pollutants, NOX is rather challenging to remove. The main treatment method is catalytic reduction with plenty of reducing agents, which lacks any effective control in an open air environment such as urban spaces. It is necessary to seek a self-powered electrochemical process for environmental treatment. The triboelectric nanogenerator (TENG), a developing technology with various advantages, is widely used in energy and environmental monitoring and cleaning. In this work, a radial-engine-shaped TENG system with five stacked TENGs is designed to synchronously absorb NOX and degrade its main enrichment forms of nitrate and nitrite in aqueous solution. In addition, the system possesses inherent phase differences and outputs continuous direct current after rectification. Moreover, we demonstrated that, driven by artificial wind at a speed of 6 m/s, the NOX generated by a chemical method was effectively degraded by the radial-engine-shaped TENG system.

19.
Adv Mater ; : e1907249, 2020 Feb 03.
Artigo em Inglês | MEDLINE | ID: mdl-32009275

RESUMO

It is well known that the photovoltaic effect produces a direct current (DC) under solar illumination owing to the directional separation of light-excited charge carriers at the p-n junction, with holes flowing to the p-side and electrons flowing to the n-side. Here, it is found that apart from the DC generated by the conventional p-n photovoltaic effect, there is another new type of photovoltaic effect that generates alternating current (AC) in the nonequilibrium states when the illumination light periodically shines at the junction/interface of materials. The peak current of AC at high switching frequency can be much higher than that from DC. The AC cannot be explained by the established mechanisms for conventional photovoltaics; instead, it is suggested to be a result of the relative shift and realignment between the quasi-Fermi levels of the semiconductors adjacent to the junction/interface under the nonequilibrium conditions, which results in electron flow in the external circuit back and forth to balance the potential difference between two electrodes. By virtue of this effect, the device can work as a high-performance broadband photodetector with extremely high sensitivity under zero bias; it can also work as a remote power source providing extra power output in addition to the conventional photovoltaic effect.

20.
Nat Commun ; 11(1): 326, 2020 01 16.
Artigo em Inglês | MEDLINE | ID: mdl-31949147

RESUMO

Bioinspired electronics are rapidly promoting advances in artificial intelligence. Emerging AI applications, e.g., autopilot and robotics, increasingly spur the development of power devices with new forms. Here, we present a strain-controlled power device that can directly modulate the output power responses to external strain at a rapid speed, as inspired by human reflex. By using the cantilever-structured AlGaN/AlN/GaN-based high electron mobility transistor, the device can control significant output power modulation (2.30-2.72 × 103 W cm-2) with weak mechanical stimuli (0-16 mN) at a gate bias of 1 V. We further demonstrate the acceleration-feedback-controlled power application, and prove that the output power can be effectively adjusted at real-time in response to acceleration changes, i.e., ▵P of 72.78-132.89 W cm-2 at an acceleration of 1-5 G at a supply voltage of 15 V. Looking forward, the device will have great significance in a wide range of AI applications, including autopilot, robotics, and human-machine interfaces.


Assuntos
Inteligência Artificial , Reflexo/fisiologia , Robótica/instrumentação , Robótica/métodos , Transistores Eletrônicos , Compostos de Alumínio/química , Técnicas Eletroquímicas/instrumentação , Técnicas Eletroquímicas/métodos , Elétrons , Gálio/química , Humanos
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