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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(11): 12540-12552, 2019 Nov 26.
Artigo em Inglês | MEDLINE | ID: mdl-31617700

RESUMO

Dual-functional devices that can simultaneously detect light and emit light have a tremendous appeal for multiple applications, including displays, sensors, defense, and high-speed optical communication. Despite the tremendous efforts of scientists, the progress of integration of a phototransistor, where the built-in electric field separates the photogenerated excitons, and a light-emitting diode, where the radiative recombination can be enhanced by band offset, into a single device remains a challenge. Combining the superior properties of perovskite quantum dots (PQDs) and graphene, here we report a light-emissive, ultrasensitive, ultrafast, and broadband vertical phototransistor that can simultaneously act as an efficient photodetector and light emitter within a single device. The estimated value of the external quantum efficiency of the vertical phototransistor is ∼1.2 × 1010% with a photoresponsivity of >109 A W-1 and a response time of <50 µs, which exceed all the presently reported vertical phototransistor devices. We also demonstrate that the modulation of the Dirac point of graphene efficiently tunes both amplitude and polarity of the photocurrent. The device exhibits a green emission having a quantum efficiency of 5.6%. The moisture-insensitive and environmentally stable, light-emissive, ultrafast, and ultrasensitive broadband phototransistor creates a useful route for dual-functional optoelectronic devices.

3.
J Formos Med Assoc ; 2019 Sep 12.
Artigo em Inglês | MEDLINE | ID: mdl-31522970

RESUMO

Cancer is the leading cause of death in Taiwan, and the overall incidence rate has gradually increased. The four most common cancers in Taiwan are colorectal, lung, breast and liver cancers. With the rise in incidence, the clinical use and costs of all anticancer drugs have steadily increased. The costs of novel therapeutics, such as targeted therapies and immunotherapy were accounted almost two-third of all antineoplastic agents in Taiwan. Moving forward, it will be necessary to discuss the economic impacts to clinical use of new therapeutics, while continuing to monitor and improve the quality of cancer therapy. In this review, we describe the epidemiology, disease screening policies and medication treatment policies for colorectal, lung, breast and liver cancer. We focus on the recent developments in cancer therapeutics, discuss the use of biomarkers, and finally consider the costs and the recent advances of anticancer medications in Taiwan.

4.
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.

5.
ACS Appl Mater Interfaces ; 11(29): 26518-26527, 2019 Jul 24.
Artigo em Inglês | MEDLINE | ID: mdl-31283174

RESUMO

Two-dimensional (2D) material nanocomposites have emerged as a material system for discovering new physical phenomena and developing novel devices. However, because of the low density of states of most two-dimensional materials such as graphene, the heterostructure of nanocomposites suffers from an enhanced depletion region, which can greatly reduce the efficiency of the charge carrier transfer and deteriorate the device performance. To circumvent this difficulty, here we propose an alternative approach by inserting a second 2D mediator with a heavy effective mass having a large density of states in-between the heterojunction of 2D nanocomposites. The mediator can effectively reduce the depletion region and form a type-II band alignment, which can speed up the dissociation of electron-hole pairs and enhance charge carrier transfer. To illustrate the principle, we demonstrate a novel stretchable photodetector based on the combination of graphene/ReS2/perovskite quantum dots. Two-dimensional ReS2 acts as a mediator in-between highly absorbing perovskite quantum dots and a high-mobility graphene channel and a thiol-based linker between the ReS2 and the perovskite. It is found that the optical sensitivity can be enhanced by 22 times. This enhancement was ascribed to the improvement of the charge transfer efficiency as evidenced by optical spectroscopy measurements. The produced photosensors are capable of reaching the highest reported value of photoresponsivity (>107 A W-1) and detectivity compared to previously studied stretchable devices. Mechanical robustness with tolerable strain up to 100% and excellent stability make our device ideal for future wearable electronics.

6.
ACS Appl Mater Interfaces ; 11(27): 24269-24278, 2019 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-31250634

RESUMO

Two-dimensional ternary materials are attracting widespread interest because of the additional degree of freedom available to tailor the material property for a specific application. An In1-xSnxSe phototransistor possessing tunable ultrahigh mobility by Sn-doping engineering is demonstrated in this study. A striking feature of In1-xSnxSe flakes is the reduction in the oxide phase compared to undoped InSe, which is validated by spectroscopic analyses. Moreover, first-principles density functional calculations performed for the In1-xSnxSe crystal system reveal the same effective mass when doped with Sn atoms. Hence, because of an increased lifetime owing to the enhanced crystal quality, the carriers in In1-xSnxSe have higher mobility than in InSe. The internally boosted electrical properties of In1-xSnxSe exhibit ultrahigh mobility of 2560 ± 240 cm2 V-1 s-1 by suppressing the interfacial traps with substrate modification and channel encapsulation. As a phototransistor, the ultrathin In1-xSnxSe flakes are highly sensitive with a detectivity of 1014 Jones. It possesses a large photoresponsivity and photogain (Vg = 40 V) as high as 3 × 105 A W-1 and 0.5 × 106, respectively. The obtained results outperform all previously reported performances of InSe-based devices. Thus, the doping-engineered In1-xSnxSe-layered semiconductor finds a potential application in optoelectronics and meets the demand for faster electronic technology.

7.
Microsc Res Tech ; 82(6): 709-719, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30741460

RESUMO

Tuberculosis (TB) remains the leading cause of morbidity and mortality from infectious disease in developing countries. The sputum smear microscopy remains the primary diagnostic laboratory test. However, microscopic examination is always time-consuming and tedious. Therefore, an effective computer-aided image identification system is needed to provide timely assistance in diagnosis. The current identification system usually suffers from complex color variations of the images, resulting in plentiful of false object detection. To overcome the dilemma, we propose a two-stage Mycobacterium tuberculosis identification system, consisting of candidate detection and classification using convolution neural networks (CNNs). The refined Faster region-based CNN was used to distinguish candidates of M. tuberculosis and the actual ones were classified by utilizing CNN-based classifier. We first compared three different CNNs, including ensemble CNN, single-member CNN, and deep CNN. The experimental results showed that both ensemble and deep CNNs were on par with similar identification performance when analyzing more than 19,000 images. A much better recall value was achieved by using our proposed system in comparison with conventional pixel-based support vector machine method for M. tuberculosis bacilli detection.


Assuntos
Processamento de Imagem Assistida por Computador/métodos , Microscopia/métodos , Mycobacterium tuberculosis/isolamento & purificação , Escarro/microbiologia , Tuberculose Pulmonar/diagnóstico , Humanos , Mycobacterium tuberculosis/citologia
8.
ACS Appl Mater Interfaces ; 11(4): 4649-4653, 2019 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-30628434

RESUMO

Light-based information processing has the potential to increase speed, security, and scalability of electronic devices if issues in the device complexity could be resolved. We here demonstrate an integrated nanoelectronic device that can combine, store, and manipulate optical and electronic information. Employing a mechanically flexible and multilayered structure, a device is realized that shows memristive behavior. Illumination is shown to control the device operation in several unique ways. First, the device produces photocurrent that allows us to read out the device state in a self-powered manner. More importantly, a varying light intensity modulates the switching transition in a proportional manner that is akin to a neuron with variable plasticity and which can be taught and queried using either light or electrical inputs. This behavior enables a multilevel light-controlled logic and teaching schemes that can be applied to light-based communication devices and provides a route toward ubiquitous and low-cost sensors for future internet of things applications.

9.
ACS Nano ; 12(12): 11847-11859, 2018 Dec 26.
Artigo em Inglês | MEDLINE | ID: mdl-30352157

RESUMO

Production of multicolor or multiple wavelength lasers over the full visible-color spectrum from a single chip device has widespread applications, such as superbright solid-state lighting, color laser displays, light-based version of Wi-Fi (Li-Fi), and bioimaging, etc. However, designing such lasing devices remains a challenging issue owing to the material requirements for producing multicolor emissions and sophisticated design for producing laser action. Here we demonstrate a simple design and highly efficient single segment white random laser based on solution-processed NaYF4:Yb/Er/Tm@NaYF4:Eu core-shell nanoparticles assisted by Au/MoO3 multilayer hyperbolic meta-materials. The multicolor lasing emitted from core-shell nanoparticles covering the red, green, and blue, simultaneously, can be greatly enhanced by the high photonic density of states with a suitable design of hyperbolic meta-materials, which enables decreasing the energy consumption of photon propagation. As a result, the energy upconversion emission is enhanced by ∼50 times with a drastic reduction of the lasing threshold. The multiple scatterings arising from the inherent nature of the disordered nanoparticle matrix provide a convenient way for the formation of closed feedback loops, which is beneficial for the coherent laser action. The experimental results were supported by the electromagnetic simulations derived from the finite-difference time-domain (FDTD) method. The approach shown here can greatly simplify the design of laser structures with color-tunable emissions, which can be extended to many other material systems. Together with the characteristics of angle free laser action, our device provides a promising solution toward the realization of many laser-based practical applications.

10.
Nanoscale ; 10(39): 18642-18650, 2018 Oct 21.
Artigo em Inglês | MEDLINE | ID: mdl-30260359

RESUMO

Flexible optoelectronic devices facilitated by the piezotronic effect have important applications in the near future in many different fields ranging from solid-state lighting to biomedicine. Two-dimensional materials possessing extraordinary mechanical strength and semiconducting properties are essential for realizing nanopiezotronics and piezo-phototronics. Here, we report the first demonstration of piezo-phototronic properties in In1-xSnxSe flexible devices by applying systematic mechanical strain under photoexcitation. Interestingly, we discover that the dark current and photocurrent are increased by five times under a bending strain of 2.7% with a maximum photoresponsivity of 1037 AW-1. In addition, the device can act as a strain sensor with a strain sensitivity up to 206. Based on these values, the device outperforms the same class of devices in two-dimensional materials. The underlying mechanism responsible for the discovered behavior can be interpreted in terms of piezoelectric potential gating, allowing the device to perform like a phototransistor. The strain-induced gate voltage assists in the efficient separation of photogenerated charge carriers and enhances the mobility of In1-xSnxSe, resulting in good performance on a freeform surface. Thus, our multifunctional device is useful for the development of a variety of advanced applications and will help meet the demand of emerging technologies.

11.
ACS Nano ; 12(9): 9596-9607, 2018 09 25.
Artigo em Inglês | MEDLINE | ID: mdl-30199626

RESUMO

Visible blind near-infrared (NIR) photodetection is essential when it comes to weapons used by military personnel, narrow band detectors used in space navigation systems, medicine, and research studies. The technological field of filterless visible blind, NIR omnidirectional photodetection and wearability is at a preliminary stage. Here, we present a filterless and lightweight design for a visible blind and wearable NIR photodetector capable of harvesting light omnidirectionally. The filterless NIR photodetector comprises the integration of distinct features of lanthanide-doped upconversion nanoparticles (UCNPs), graphene, and micropyramidal poly(dimethylsiloxane) (PDMS) film. The lanthanide-doped UCNPs are designed such that the maximum narrow band detection of NIR is easily accomplished by the photodetector even in the presence of visible light sources. Especially, the 4f n electronic configuration of lanthanide dopant ions provides for a multilevel hierarchical energy system that provides for longer lifetime of the excited states for photogenerated charge carriers to transfer to the graphene layer. The graphene layer can serve as an outstanding conduction path for photogenerated charge carrier transfer from UCNPs, and the flexible micropyramidal PDMS substrate provides an excellent platform for omnidirectional NIR light detection. Owing to these advantages, a photoresponsivity of ∼800 AW-1 is achieved by the NIR photodetector, which is higher than the values ever reported by UCNPs-based photodetectors. In addition, the photodetector is stretchable, durable, and transparent, making it suitable for next-generation wearable optoelectronic devices.

12.
ACS Appl Mater Interfaces ; 10(20): 17393-17400, 2018 May 23.
Artigo em Inglês | MEDLINE | ID: mdl-29706071

RESUMO

In recent years, flexible magnetoelectronics has attracted a great attention for its intriguing functionalities and potential applications, such as healthcare, memory, soft robots, navigation, and touchless human-machine interaction systems. Here, we provide the first attempt to demonstrate a new type of magneto-piezoresistance device, which possesses an ultrahigh sensitivity with several orders of resistance change under an external magnetic field (100 mT). In our device, Fe-Ni alloy powders are embedded in the silver nanowire-coated micropyramid polydimethylsiloxane films. Our devices can not only serve as an on/off switch but also act as a sensor that can detect different magnetic fields because of its ultrahigh sensitivity, which is very useful for the application in analog signal communication. Moreover, our devices contain several key features, including large-area and easy fabrication processes, fast response time, low working voltage, low power consumption, excellent flexibility, and admirable compatibility onto a freeform surface, which are the critical criteria for the future development of touchless human-machine interaction systems. On the basis of all of these unique characteristics, we have demonstrated a nontouch piano keyboard, instantaneous magnetic field visualization, and autonomous power system, making our new devices be integrable with magnetic field and enable to be implemented into our daily life applications with unfamiliar human senses. Our approach therefore paves a useful route for the development of wearable electronics and intelligent systems.

13.
Nano Lett ; 18(5): 3221-3228, 2018 05 09.
Artigo em Inglês | MEDLINE | ID: mdl-29694049

RESUMO

Organic-inorganic hybrid two-dimensional (2D) perovskites have recently attracted great attention in optical and optoelectronic applications due to their inherent natural quantum-well structure. We report the growth of high-quality millimeter-sized single crystals belonging to homologous two-dimensional (2D) hybrid organic-inorganic Ruddelsden-Popper perovskites (RPPs) of (BA)2(MA) n-1Pb nI3 n+1 ( n = 1, 2, and 3) by a slow evaporation at a constant-temperature (SECT) solution-growth strategy. The as-grown 2D hybrid perovskite single crystals exhibit excellent crystallinity, phase purity, and spectral uniformity. Low-threshold lasing behaviors with different emission wavelengths at room temperature have been observed from the homologous 2D hybrid RPP single crystals. Our result demonstrates that solution-growth homologous organic-inorganic hybrid 2D perovskite single crystals open up a new window as a promising candidate for optical gain media.

14.
Sci Rep ; 8(1): 2720, 2018 02 09.
Artigo em Inglês | MEDLINE | ID: mdl-29426912

RESUMO

Random laser with intrinsically uncomplicated fabrication processes, high spectral radiance, angle-free emission, and conformal onto freeform surfaces is in principle ideal for a variety of applications, ranging from lighting to identification systems. In this work, a white random laser (White-RL) with high-purity and high-stability is designed, fabricated, and demonstrated via the cost-effective materials (e.g., organic laser dyes) and simple methods (e.g., all-solution process and self-assembled structures). Notably, the wavelength, linewidth, and intensity of White-RL are nearly isotropic, nevertheless hard to be achieved in any conventional laser systems. Dynamically fine-tuning colour over a broad visible range is also feasible by on-chip integration of three free-standing monochromatic laser films with selective pumping scheme and appropriate colour balance. With these schematics, White-RL shows great potential and high application values in high-brightness illumination, full-field imaging, full-colour displays, visible-colour communications, and medical biosensing.

15.
ACS Sens ; 3(1): 99-105, 2018 01 26.
Artigo em Inglês | MEDLINE | ID: mdl-29192501

RESUMO

Deep learning and analysis of heavy metal concentration are very crucial to our life, for it plays an essential role in both environmental and human health. In this paper, we developed a new Cu (II) ions sensor made by all organic material with bending and stretching properties. The new sensor consists of chlorophyll-a extracted from fresh leaves of Common Garcinia, plant fiber and with the use of PDMS as a substrate. Fluorescence spectra study shows that chlorophyll-a is significantly much more sensitive to Cu (II) ions than any other heavy metal ions and the device sensitivity outperforms all the Cu (II) ions sensors ever reported. The result fully shows the selectivity of chlorophyll-a toward Cu (II) ions. Bending and stretching tests show that the sensor has an outstanding durability, which can be used to develop accompanying applications, such as real-time sampling and the analysis of Cu (II) concentration specified in athlete's sweat or patients with brain death and Parkinson's disease.


Assuntos
Clorofila A/química , Cobre/análise , Cobre/química , Dimetilpolisiloxanos , Elasticidade , Íons , Maleabilidade , Sensibilidade e Especificidade , Espectrometria de Fluorescência
16.
Adv Mater ; 29(43)2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-28991394

RESUMO

A stretchable, flexible, and bendable random laser system capable of lasing in a wide range of spectrum will have many potential applications in next- generation technologies, such as visible-spectrum communication, superbright solid-state lighting, biomedical studies, fluorescence, etc. However, producing an appropriate cavity for such a wide spectral range remains a challenge owing to the rigidity of the resonator for the generation of coherent loops. 2D materials with wrinkled structures exhibit superior advantages of high stretchability and a suitable matrix for photon trapping in between the hill and valley geometries compared to their flat counterparts. Here, the intriguing functionalities of wrinkled reduced graphene oxide, single-layer graphene, and few-layer hexagonal boron nitride, respectively, are utilized to design highly stretchable and wearable random laser devices with ultralow threshold. Using methyl-ammonium lead bromide perovskite nanocrystals (PNC) to illustrate the working principle, the lasing threshold is found to be ≈10 µJ cm-2 , about two times less than the lowest value ever reported. In addition to PNC, it is demonstrated that the output lasing wavelength can be tuned using different active materials such as semiconductor quantum dots. Thus, this study is very useful for the future development of high-performance wearable optoelectronic devices.

17.
Sci Rep ; 7(1): 10002, 2017 08 30.
Artigo em Inglês | MEDLINE | ID: mdl-28855573

RESUMO

Integrating different dimentional materials on vertically stacked p-n hetero-junctions have facinated a considerable scrunity and can open up excellent feasibility with various functionalities in opto-electronic devices. Here, we demonstrate that vertically stacked p-GaN/SiO2/n-MoS2/Graphene heterostructures enable to exhibit prominent dual opto-electronic characteristics, including efficient photo-detection and light emission, which represents the emergence of a new class of devices. The photoresponsivity was found to achieve as high as ~10.4 AW-1 and the detectivity and external quantum efficiency were estimated to be 1.1 × 1010 Jones and ~30%, respectively. These values are superier than most reported hererojunction devices. In addition, this device exhibits as a self-powered photodetector, showing a high responsivity and fast response speed. Moreover, the device demonstrates the light emission with low turn-on voltage (~1.0 V) which can be realized by electron injection from graphene electrode and holes from GaN film into monolayer MoS2 layer. These results indicate that with a suitable choice of band alignment, the vertical stacking of materials with different dimentionalities could be significant potential for integration of highly efficient heterostructures and open up feasible pathways towards integrated nanoscale multi-functional optoelectronic devices for a variety of applications.

18.
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.

19.
ACS Appl Mater Interfaces ; 8(27): 17382-8, 2016 Jul 13.
Artigo em Inglês | MEDLINE | ID: mdl-27345102

RESUMO

Gas sensors play an important role in numerous fields, covering a wide range of applications, including intelligent systems and detection of harmful and toxic gases. Even though they have attracted much attention, the response time on the order of seconds to minutes is still very slow. To circumvent the existing problems, here, we provide a seminal attempt with the integration of graphene, semiconductor, and an addition sieve layer forming a nanocomposite gas sensor with ultrahigh sensitivity and ultrafast response. The designed sieve layer has a suitable band structure that can serve as a blocking layer to prevent transfer of the charges induced by adsorbed gas molecules into the underlying semiconductor layer. We found that the sensitivity can be reduced to the parts per million level, and the ultrafast response of around 60 ms is unprecedented compared with published graphene-based gas sensors. The achieved high performance can be interpreted well by the large change of the Fermi level of graphene due to its inherent nature of the low density of states and blocking of the sieve layer to prevent charge transfer from graphene to the underlying semiconductor layer. Accordingly, our work is very useful and timely for the development of gas sensors with high performance for practical applications.

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