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1.
Artigo em Inglês | MEDLINE | ID: mdl-32013376

RESUMO

The emergence of self-healing devices in recent years has drawn a great amount of attention in both academics and industry. Self-healed devices can autonomically restore a rupture as unexpected destruction occurs, which can efficiently prolong the life span of the devices; hence, they have an enhanced durability and decreased replacement cost. As a result, integration of wearable devices with self-healed electronics has become an indispensable issue in smart wearable devices. In this study, we present the first self-powered, self-healed, and wearable ultraviolet (UV) photodetector based on the integration of agarose/poly(vinyl alcohol) (PVA) double network (DN) hydrogels, which have the advantages of good mechanical strength, self-healing ability, and tolerability of multiple types of damage. With the integration of a DN hydrogel substrate, the photodetector enables 90% of the initial efficiency to be restored after five healing cycles, and each rapid healing time is suppressed to only 10 s. The proposed device has several merits, including having an all spray coating, self-sustainability, biocompatibility, good sensitivity, mechanical flexibility, and an outstanding healing ability, which are all essential to build smart electronic systems. The unprecedented self-healed photodetector expands the future scope of electronic skin design, and it also offers a new platform for the development of next-generation wearable electronics.

2.
ACS Nano ; 13(8): 8977-8985, 2019 Aug 27.
Artigo em Inglês | MEDLINE | ID: mdl-31390182

RESUMO

Self-healing technology promises a generation of innovation in cross-cutting subjects ranging from electronic skins, to wearable electronics, to point-of-care biomedical sensing modules. Recently, scientists have successfully pulled off significant advances in self-healing components including sensors, energy devices, transistors, and even integrated circuits. Lasers, one of the most important light sources, integrated with autonomous self-healability should be endowed with more functionalities and opportunities; however, the study of self-healing lasers is absent in all published reports. Here, the soft and self-healable random laser (SSRL) is presented. The SSRL can not only endure extreme external strain but also withstand several cutting/healing test cycles. Particularly, the damaged SSRL enables its functionality to be restored within just few minutes without the need of additional energy, chemical/electrical agents, or other healing stimuli, truly exhibiting a supple yet robust laser prototype. It is believed that SSRL can serve as a vital building block for next-generation laser technology as well as follow-on self-healing optoelectronics.

3.
Adv Sci (Weinh) ; 6(5): 1801883, 2019 Mar 06.
Artigo em Inglês | MEDLINE | ID: mdl-30886807

RESUMO

Developing nimble, shape-adaptable, conformable, and widely implementable energy harvesters with the capability to scavenge multiple renewable and ambient energy sources is highly demanded for distributed, remote, and wearable energy uses to meet the needs of internet of things. Here, the first single waterproof and fabric-based multifunctional triboelectric nanogenerator (WPF-MTENG) is presented, which can produce electricity from both natural tiny impacts (rain and wind) and body movements, and can not only serve as a flexible, adaptive, wearable, and universal energy collector but also act as a self-powered, active, fabric-based sensor. The working principle comes from a conjunction of contact triboelectrification and electrostatic induction during contact/separation of internal soft fabrics. The structural/material designs of the WPF-MTENG are systematically studied to optimize its performance, and its outputs under different conditions of rain, wind, and various body movements are comprehensively investigated. Its applicability is practically demonstrated in various objects and working situations to gather ambient energy. Lastly, a WPF-MTENG-based keypad as self-powered human-system interfaces is demonstrated on a garment for remotely controlling a music-player system. This multifunctional WPF-MTENG, which is as flexible as clothes, not only presents a promising step toward democratic collections of alternative energy but also provides a new vision for wearable technologies.

4.
Adv Mater ; 30(28): e1801114, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-29869431

RESUMO

Robots that can move, feel, and respond like organisms will bring revolutionary impact to today's technologies. Soft robots with organism-like adaptive bodies have shown great potential in vast robot-human and robot-environment applications. Developing skin-like sensory devices allows them to naturally sense and interact with environment. Also, it would be better if the capabilities to feel can be active, like real skin. However, challenges in the complicated structures, incompatible moduli, poor stretchability and sensitivity, large driving voltage, and power dissipation hinder applicability of conventional technologies. Here, various actively perceivable and responsive soft robots are enabled by self-powered active triboelectric robotic skins (tribo-skins) that simultaneously possess excellent stretchability and excellent sensitivity in the low-pressure regime. The tribo-skins can actively sense proximity, contact, and pressure to external stimuli via self-generating electricity. The driving energy comes from a natural triboelectrification effect involving the cooperation of contact electrification and electrostatic induction. The perfect integration of the tribo-skins and soft actuators enables soft robots to perform various actively sensing and interactive tasks including actively perceiving their muscle motions, working states, textile's dampness, and even subtle human physiological signals. Moreover, the self-generating signals can drive optoelectronic devices for visual communication and be processed for diverse sophisticated uses.


Assuntos
Pele , Eletricidade , Humanos , Movimento (Física) , Pressão , Robótica
5.
ACS Appl Mater Interfaces ; 10(17): 14708-14715, 2018 May 02.
Artigo em Inglês | MEDLINE | ID: mdl-29659250

RESUMO

Harvesting energy available from ambient environment is highly desirable for powering personal electronics and health applications. Due to natural process and human activities, steam can be produced by boilers, human perspiration, and the wind exists ubiquitously. In the outdoor environment, these two phenomena usually exist at the same place, which contain heat and mechanical energies simultaneously. However, previous studies have isolated them as separate sources of energy to harvest and hence failed to utilize them effectively. Herein, we present unique hybrid nanogenerators for individually/simultaneously harvesting thermal energy from water vapors and mechanical energy from intermittent wind blowing from the bottom side, which consist of a wind-driven triboelectric nanogenerator (TENG) and pyroelectric-piezoelectric nanogenerators (PPENGs). The output power of the PPENG and the TENG can be up to about 184.32 µW and 4.74 mW, respectively, indicating the TENG plays the dominant role. Our hybrid nanogenerators could provide different applications such as to power digital watch and enable self-powered sensing with wireless transmission. The device could also be further integrated into a face mask for potentially wearable applications. This work not only provides a promising approach for renewable energy harvesting but also enriches potential applications for self-powered systems and wireless sensors.

6.
Adv Mater ; 30(14): e1705918, 2018 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-29457281

RESUMO

Functional polymers possess outstanding uniqueness in fabricating intelligent devices such as sensors and actuators, but they are rarely used for converting mechanical energy into electric power. Here, a vitrimer based triboelectric nanogenerator (VTENG) is developed by embedding a layer of silver nanowire percolation network in a dynamic disulfide bond-based vitrimer elastomer. In virtue of covalent dynamic disulfide bonds in the elastomer matrix, a thermal stimulus enables in situ healing if broken, on demand reconfiguration of shape, and assembly of more sophisticated structures of VTENG devices. On rupture or external damage, the structural integrity and conductivity of VTENG are restored under rapid thermal stimulus. The flexible and stretchable VTENG can be scaled up akin to jigsaw puzzles and transformed from 2D to 3D structures. It is demonstrated that this self-healable and shape-adaptive VTENG can be utilized for mechanical energy harvesters and self-powered tactile/pressure sensors with extended lifetime and excellent design flexibility. These results show that the incorporation of organic materials into electronic devices can not only bestow functional properties but also provide new routes for flexible device fabrication.

7.
Adv Mater ; 30(8)2018 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-29318681

RESUMO

Growing demand in portable electronics raises a requirement to electronic devices being stretchable, deformable, and durable, for which functional polymers are ideal choices of materials. Here, the first transformable smart energy harvester and self-powered mechanosensation sensor using shape memory polymers is demonstrated. The device is based on the mechanism of a flexible triboelectric nanogenerator using the thermally triggered shape transformation of organic materials for effectively harvesting mechanical energy. This work paves a new direction for functional polymers, especially in the field of mechanosensation for potential applications in areas such as soft robotics, biomedical devices, and wearable electronics.

8.
ACS Nano ; 11(8): 7600-7607, 2017 08 22.
Artigo em Inglês | MEDLINE | ID: mdl-28651049

RESUMO

An integrated random laser based on green materials with dissolubility and recyclability is created and demonstrated. The dissolvable and recyclable random laser (DRRL) can be dissolved in water, accompanying the decay of emission intensity and the increment in lasing threshold. Furthermore, the DRRL can be reused after the process of deionized treatment, exhibiting excellent reproducibility with several recycling processes.

9.
IEEE Trans Biomed Eng ; 64(9): 2152-2162, 2017 09.
Artigo em Inglês | MEDLINE | ID: mdl-28113297

RESUMO

OBJECTIVE: This study aimed to verify and compare the accuracy of energy expenditure (EE) prediction models using shoe-based motion detectors with embedded accelerometers. METHODS: Three physical activity (PA) datasets (unclassified, recognition, and intensity segmentation) were used to develop three prediction models. A multiple classification flow and these models were used to estimate EE. The "unclassified" dataset was defined as the data without PA recognition, the "recognition" as the data classified with PA recognition, and the "intensity segmentation" as the data with intensity segmentation. The three datasets contained accelerometer signals (quantified as signal magnitude area (SMA)) and net heart rate (HRnet). The accuracy of these models was assessed according to the deviation between physically measured EE and model-estimated EE. RESULTS: The variance between physically measured EE and model-estimated EE expressed by simple linear regressions was increased by 63% and 13% using SMA and HRnet, respectively. The accuracy of the EE predicted from accelerometer signals is influenced by the different activities that exhibit different count-EE relationships within the same prediction model. CONCLUSION: The recognition model provides a better estimation and lower variability of EE compared with the unclassified and intensity segmentation models. SIGNIFICANCE: The proposed shoe-based motion detectors can improve the accuracy of EE estimation and has great potential to be used to manage everyday exercise in real time.


Assuntos
Acelerometria/instrumentação , Modelos Biológicos , Monitorização Ambulatorial/instrumentação , Consumo de Oxigênio/fisiologia , Sapatos , Acelerometria/métodos , Adulto , Simulação por Computador , Sistemas de Computação , Metabolismo Energético/fisiologia , Desenho de Equipamento , Análise de Falha de Equipamento , Humanos , Masculino , Monitorização Ambulatorial/métodos , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
10.
ACS Nano ; 10(11): 10580-10588, 2016 11 22.
Artigo em Inglês | MEDLINE | ID: mdl-27934070

RESUMO

Recently, a self-charging power unit consisting of an energy harvesting device and an energy storage device set the foundation for building a self-powered wearable system. However, the flexibility of the power unit working under extremely complex deformations (e.g., stretching, twisting, and bending) becomes a key issue. Here, we present a prototype of an all-in-one shape-adaptive self-charging power unit that can be used for scavenging random body motion energy under complex mechanical deformations and then directly storing it in a supercapacitor unit to build up a self-powered system for wearable electronics. A kirigami paper based supercapacitor (KP-SC) was designed to work as the flexible energy storage device (stretchability up to 215%). An ultrastretchable and shape-adaptive silicone rubber triboelectric nanogenerator (SR-TENG) was utilized as the flexible energy harvesting device. By combining them with a rectifier, a stretchable, twistable, and bendable, self-charging power package was achieved for sustainably driving wearable electronics. This work provides a potential platform for the flexible self-powered systems.

11.
Adv Mater ; 28(45): 10024-10032, 2016 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-27678014

RESUMO

Electric eel-skin-inspired mechanically durable and super-stretchable nanogenerator is demonstrated for the first time by using triboelectric effect. This newly designed nanogenerator can produce electricity by touch or tapping despite under various extreme mechanical deformations or even after experiencing damage. This device can be used not only as deformable and wearable power source but also as fully autonomous and self-sufficient adaptive electronic skin system.

12.
ACS Appl Mater Interfaces ; 8(1): 466-71, 2016 Jan 13.
Artigo em Inglês | MEDLINE | ID: mdl-26696193

RESUMO

Stretchable devices possess great potential in a wide range of applications, such as biomedical and wearable gadgets and smart skin, which can be integrated with the human body. Because of their excellent flexibility, two-dimensional (2D) materials are expected to play an important role in the fabrication of stretchable devices. However, only a limited number of reports have been devoted to investigating stretchable devices based on 2D materials, and the stretchabilities were restricted in a very small strain. Moreover, there is no report related to the stretchable photodetectors derived from 2D materials. Herein, we demonstrate a highly stretchable and sensitive photodetector based on hybrid graphene and graphene quantum dots (GQDs). A unique rippled structure of poly(dimethylsiloxane) is used to support the graphene layer, which can be stretched under an external strain far beyond published reports. The ripple of the device can overcome the native stretchability limit of graphene and enhance the carrier generation in GQDs due to multiple reflections of photons between the ripples. Our strategy presented here can be extended to many other material systems, including other 2D materials. It therefore paves a key step for the development of stretchable electronics and optical devices.

13.
Adv Mater ; 28(22): 4441-8, 2016 06.
Artigo em Inglês | MEDLINE | ID: mdl-26179120

RESUMO

Mechanically durable stretchable trans-istors are fabricated using carbon nanotube electrical components and tough thermoplastic elastomers. After an initial conditioning step, the electrical characteristics remain constant with strain. The strain-dependent characteristics are similar in orthogonal stretching directions. Devices can be impacted with a hammer and punctured with a needle while remaining functional and stretchable.

14.
Small ; 11(24): 2946-54, 2015 Jun 24.
Artigo em Inglês | MEDLINE | ID: mdl-25711378

RESUMO

Low-bandgap diketopyrrolopyrrole (DPP)-based polymers are used for the selective dispersion of semiconducting single-walled carbon nanotubes (s-SWCNTs). Through rational molecular design to tune the polymer-SWCNT interactions, highly selective dispersions of s-SWCNTs with diameters mainly around 1.5 nm are achieved. The influences of the polymer alkyl side-chain substitution (i.e., branched vs linear side chains) on the dispersing yield and selectivity of s-SWCNTs are investigated. Introducing linear alkyl side chains allows increased polymer-SWCNT interactions through close π-π stacking and improved C-H-π interactions. This work demonstrates that polymer side-chain engineering is an effective method to modulate the polymer-SWCNT interactions and thereby affecting both critical parameters in dispersing yield and selectivity. Using these sorted s-SWCNTs, high-performance SWCNT network thin-film transistors are fabricated. The solution-deposited s-SWCNT transistors yield simultaneously high mobilities of 41.2 cm(2) V(-1) s(-1) and high on/off ratios of greater than 10(4) . In summary, low-bandgap DPP donor-acceptor polymers are a promising class of polymers for selective dispersion of large-diameter s-SWCNTs.

16.
ACS Nano ; 8(3): 2609-17, 2014 03 25.
Artigo em Inglês | MEDLINE | ID: mdl-24484388

RESUMO

We describe herein a high-yield method to selectively disperse semiconducting CoMoCAT (CO disproportionation on Co-Mo catalysts) single-walled carbon nanotubes (SWNTs) with regioregular poly(3-alkylthiophenes) polymers. We observed that the dispersion yield was directly related to the length of the polymer's alkyl side chains. Molecular dynamics simulations in explicit toluene (real toluene molecules) indicate that polythiophenes with longer alkyl side chains bind strongly to SWNTs, due to the increased overall surface contact area with the nanotube. Furthermore, the sorting process selectively enriches smaller-diameter CoMoCAT SWNTs with larger bandgaps, which is ideal for solar cell applications. Compared to the larger diameter sorted HiPco (High-Pressure CO) SWNTs, solar cells fabricated using our sorted CoMoCAT SWNTs demonstrated higher open-circuit voltage (Voc) and infrared external quantum efficiency (EQE). The Voc achieved is the highest reported for solar cells based on SWNT absorbers under simulated AM1.5 solar illumination. Additionally, we employed the sorted CoMoCAT SWNTs to fabricate thin film transistors with excellent uniformity and device performance.

17.
Adv Mater ; 25(19): 2733-9, 2013 May 21.
Artigo em Inglês | MEDLINE | ID: mdl-23553715

RESUMO

A newly designed transferable and flexible label-like organic memory based on a graphene electrode behaves like a sticker, and can be readily placed on desired substrates or devices for diversified purposes. The memory label reveals excellent performance despite its physical presentation. This may greatly extend the memory applications in various advanced electronics and provide a simple scheme to integrate with other electronics.


Assuntos
Dispositivos de Armazenamento em Computador , Grafite/química , Microeletrodos , Compostos Orgânicos/química , Módulo de Elasticidade , Desenho de Equipamento , Análise de Falha de Equipamento , Teste de Materiais
18.
Sensors (Basel) ; 12(12): 17372-89, 2012 Dec 13.
Artigo em Inglês | MEDLINE | ID: mdl-23443403

RESUMO

The integration of the Inertial Navigation System (INS) and the Global Positioning System (GPS) is widely applied to seamlessly determine the time-variable position and orientation parameters of a system for navigation and mobile mapping applications. For optimal data fusion, the Kalman filter (KF) is often used for real-time applications. Backward smoothing is considered an optimal post-processing procedure. However, in current INS/GPS integration schemes, the KF and smoothing techniques still have some limitations. This article reviews the principles and analyzes the limitations of these estimators. In addition, an on-line smoothing method that overcomes the limitations of previous algorithms is proposed. For verification, an INS/GPS integrated architecture is implemented using a low-cost micro-electro-mechanical systems inertial measurement unit and a single-frequency GPS receiver. GPS signal outages are included in the testing trajectories to evaluate the effectiveness of the proposed method in comparison to conventional schemes.


Assuntos
Algoritmos , Sistemas de Informação Geográfica , Sistemas Microeletromecânicos , Humanos , Integração de Sistemas
19.
Sensors (Basel) ; 10(4): 2472-91, 2010.
Artigo em Inglês | MEDLINE | ID: mdl-22319258

RESUMO

A development procedure for a low-cost attitude and heading reference system (AHRS) with a self-developed three-axis rotating platform has been proposed. The AHRS consists of one 3-axis accelerometer, three single-axis gyroscopes, and one 3-axis digital compass. Both the accelerometer and gyroscope triads are based on micro electro-mechanical system (MEMS) technology, and the digital compass is based on anisotropic-magnetoresistive (AMR) technology. The calibrations for each sensor triad are readily accomplished by using the scalar calibration and the least squares methods. The platform is suitable for the calibration and validation of the low-cost AHRS and it is affordable for most laboratories. With the calibrated parameters and data fusion algorithm for the orientation estimation, the self-developed AHRS demonstrates the capabilities of compensating for the sensor errors and outputting the estimated orientation in real-time. The validation results show that the estimated orientations of the developed AHRS are within the acceptable region. This verifies the practicability of the proposed development procedure.

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