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1.
Nanotechnology ; 33(6)2021 Nov 19.
Artigo em Inglês | MEDLINE | ID: mdl-34736234

RESUMO

Artificial synapses that integrate functions of sensing, memory and computing are highly desired for developing brain-inspired neuromorphic hardware. In this work, an optoelectronic synapse based on the ZnO nanowire (NW) transistor is achieved, which can be used to emulate both the short-term and long-term synaptic plasticity. Synaptic potentiation is present when the device is stimulated by light pulses, arising from the light-induced O2desorption and the persistent photoconductivity behavior of the ZnO NW. On the other hand, synaptic depression occurs when the device is stimulated by electrical pulses in dark, which is realized by introducing a charge trapping layer in the gate dielectric to trap carriers. Simulation of a neural network utilizing the ZnO NW synapses is carried out, demonstrating a high recognition accuracy over 90% after only 20 training epochs for recognizing the Modified National Institute of Standards and Technology digits. The present nanoscale optoelectronic synapse has great potential in the development of neuromorphic visual systems.

2.
Biomed Res Int ; 2021: 6207964, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34671677

RESUMO

Colorectal cancer is a high death rate cancer until now; from the clinical view, the diagnosis of the tumour region is critical for the doctors. But with data accumulation, this task takes lots of time and labor with large variances between different doctors. With the development of computer vision, detection and segmentation of the colorectal cancer region from CT or MRI image series are a great challenge in the past decades, and there still have great demands on automatic diagnosis. In this paper, we proposed a novel transfer learning protocol, called CST, that is, a union framework for colorectal cancer region detection and segmentation task based on the transformer model, which effectively constructs the cancer region detection and its segmentation jointly. To make a higher detection accuracy, we incorporate an autoencoder-based image-level decision approach that leverages the image-level decision of a cancer slice. We also compared our framework with one-stage and two-stage object detection methods; the results show that our proposed method achieves better results on detection and segmentation tasks. And this proposed framework will give another pathway for colorectal cancer screen by way of artificial intelligence.


Assuntos
Algoritmos , Inteligência Artificial , Neoplasias Colorretais/diagnóstico por imagem , Detecção Precoce de Câncer/métodos , Processamento de Imagem Assistida por Computador/métodos , Imageamento por Ressonância Magnética/métodos , Neoplasias Colorretais/patologia , Humanos
3.
Biomed Res Int ; 2021: 2567202, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34631877

RESUMO

Breast cancer diagnosis is a critical step in clinical decision making, and this is achieved by making a pathological slide and gives a decision by the doctors, which is the method of final decision making for cancer diagnosis. Traditionally, the doctors usually check the pathological images by visual inspection under the microscope. Whole-slide images (WSIs) have supported the state-of-the-art diagnosis results and have been admitted as the gold standard clinically. However, this task is time-consuming and labour-intensive, and all of these limitations make low efficiency in decision making. Medical image processing protocols have been used for this task during the last decades and have obtained satisfactory results under some conditions; especially in the deep learning era, it has exhibited the advantages than those in the shallow learning period. In this paper, we proposed a novel breast cancer region mining framework based on deep pyramid architecture from multilevel and multiscale breast pathological WSIs. We incorporate the tissue- and cell-level information together and integrate these into a LSTM model for the final sequence modelling, which successfully keeps the WSIs' integration and is not mentioned by the prevalence frameworks. The experiment results demonstrated that our proposed framework greatly improved the detection accuracy than that only using tissue-level information.


Assuntos
Algoritmos , Neoplasias da Mama/diagnóstico , Aprendizado Profundo , Neoplasias da Mama/diagnóstico por imagem , Neoplasias da Mama/patologia , Feminino , Humanos , Processamento de Imagem Assistida por Computador
4.
Dalton Trans ; 50(46): 16984-16989, 2021 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-34612256

RESUMO

Two novel compounds, a molecular trefoil knot and a Solomon link, were constructed successfully through the cooperation of multiple π-π stacking interactions. A reversible transformation between the trefoil knot and the corresponding [2 + 2] macrocycle could be achieved by solvent- and guest-induced effects. However, the Solomon link maintains its stability in different concentrations, solvents and guest molecules. Single-crystal X-ray crystallographic data, NMR spectroscopic experiments and ESI-MS support the synthesis and structural assignments. These synthesis methods open the door to the further development of smart materials, which will push the advancement of rational design of biomaterials.


Assuntos
Compostos Macrocíclicos/síntese química , Cristalografia por Raios X , Compostos Macrocíclicos/química , Modelos Moleculares , Estrutura Molecular , Solventes/química
5.
Nanomaterials (Basel) ; 11(10)2021 Oct 19.
Artigo em Inglês | MEDLINE | ID: mdl-34685207

RESUMO

Lithium-ion capacitors (LICs) are attracting increasing attention because of their potential to bridge the electrochemical performance gap between batteries and supercapacitors. However, the commercial application of current LICs is still impeded by their inferior energy density, which is mainly due to the low capacity of the cathode. Therefore, tremendous efforts have been made in developing novel cathode materials with high capacity and excellent rate capability. Graphene-based nanomaterials have been recognized as one of the most promising cathodes for LICs due to their unique properties, and exciting progress has been achieved. Herein, in this review, the recent advances of graphene-based cathode materials for LICs are systematically summarized. Especially, the synthesis method, structure characterization and electrochemical performance of various graphene-based cathodes are comprehensively discussed and compared. Furthermore, their merits and limitations are also emphasized. Finally, a summary and outlook are presented to highlight some challenges of graphene-based cathode materials in the future applications of LICs.

6.
ACS Appl Mater Interfaces ; 13(30): 35878-35888, 2021 Aug 04.
Artigo em Inglês | MEDLINE | ID: mdl-34297521

RESUMO

Electrochemical capacitors using neutral aqueous electrolytes are safer and cheaper and allow diverse current collectors compared with the counterparts using organic or acidic/alkaline electrolytes. Two-dimensional (2D) MXenes have been demonstrated as the high-capacitive materials with high rate performance. However, MXene electrodes often exhibit a limited capacitance in neutral electrolytes, where the reversible electrochemical reactions rely greatly on the structural and surface properties of MXenes depending on their synthesis methods. Herein, a simple and highly efficient strategy, which combines HF etching of Ti3AlC2 powder and subsequent amine-assisted delamination at a low temperature, is developed to synthesize 2D Ti3C2Tx MXenes. The comprehensive results demonstrate that the enlarged interlayer spacing and the presence of more -O-containing functional groups synergistically contribute to the improvement of capacitive performance in neutral electrolytes. The 2D Ti3C2Tx MXenes show excellent electrochemical performance in various neutral electrolytes, and a high specific gravimetric capacitance of 149.8 F/g is achieved in 1.0 M Li2SO4. Furthermore, the flexible solid-state supercapacitors (SCs) with a neutral PVA/LiCl gel electrolyte possess a superior areal capacitance (163.1 mF/cm2) and high energy density (17.6 µWh/cm2 at 0.07 mW/cm2), together with high user safety. This work provides a promising guideline of synthesis strategy for high-capacitive MXenes used in neutral electrolytes, which may promote the development of safe and flexible power sources with a high energy density.

7.
Sci Technol Adv Mater ; 21(1): 768-786, 2021 Jan 06.
Artigo em Inglês | MEDLINE | ID: mdl-33488297

RESUMO

With the rapid development of conductive polymers, they have shown great potential in room-temperature chemical gas detection, as their electrical conductivity can be changed upon exposure to oxidative or reductive gas molecules at room temperature. However, due to their relatively low conductivity and high affinity toward volatile organic compounds and water molecules, they always exhibit low sensitivity, poor stability, and gas selectivity, which hinder their practical gas sensor applications. In addition, inorganic sensitive materials show totally different advantages in gas sensors, such as high sensitivity, fast response to low concentration analytes, high surface area, and versatile surface chemistry, which could complement the conducting polymers in terms of the sensing characteristics. It seems to be a win-win choice to combine inorganic sensitive materials with polymers for gas detection due to their synergistic effects, which has attracted extensive interests in gas-sensing applications. In this review, we summarize the recent development in polymer-inorganic nanocomposite based gas sensors. The roles of inorganic nanomaterials in improving the gas-sensing performances of conducting polymers are introduced and the progress of conducting polymer-inorganic nanocomposites including metal oxides, metal, carbon (carbon nanotube, graphene), and ternary composites are presented. Finally, a conclusion and a perspective in the field of gas sensors incorporating conducting polymer-inorganic nanocomposite are summarized.

8.
Nanotechnology ; 32(1): 015403, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-32947263

RESUMO

Lithium-ion capacitors (LICs) are now drawing increasing attention because of their potential to overcome the current energy limitations of supercapacitors and power limitations of lithium-ion batteries. In this work, we designed LICs by combining an electric double-layer capacitor cathode and a lithium-ion battery anode. Both the cathode and anode are derived from graphene-modified phenolic resin with tunable porosity and microstructure. They exhibit high specific capacity, superior rate capability and good cycling stability. Benefiting from the graphene-enhanced electrode materials, the all graphene-based LICs demonstrate a high working voltage (4.2 V), high energy density of 142.9 Wh kg-1, maximum power density of 12.1 kW kg-1 with energy density of 50 Wh kg-1, and long stable cycling performance (with ∼88% capacity retention after 5000 cycles). Considering the high performance of the device, the cost-effective and facile preparation process of the active materials, this all graphene-based lithium-ion capacitor could have many promising applications in energy storage systems.

9.
Annu Int Conf IEEE Eng Med Biol Soc ; 2020: 1384-1387, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-33018247

RESUMO

Survival analysis is a valid solution for cancer treatments and outcome evaluations. Due to the wide application of medical imaging and genome technology, computer-aided survival analysis has become a popular and promising area, from which we can get relatively satisfactory results. Although there are already some impressive technologies in this field, most of them make some recommendations using single-source medical data and have not combined multi-level and multi-source data efficiently. In this paper, we propose a novel pathological images and gene expression data fusion framework to perform the survival prediction. Different from previous methods, our framework can extract correlated multi-scale deep features from whole slide images (WSIs) and dimensionality reduced gene expression data respectively for jointly survival analysis. The experiment results demonstrate that the integrated multi-level image and genome features can achieve higher prediction accuracy compared with single-source features.


Assuntos
Neoplasias da Mama , Algoritmos , Mama , Neoplasias da Mama/genética , Genômica , Humanos
10.
Nanomaterials (Basel) ; 10(9)2020 Aug 29.
Artigo em Inglês | MEDLINE | ID: mdl-32872472

RESUMO

The growing demand for high performance from supercapacitors has inspired the development of porous nanocomposites using renewable and naturally available materials. In this work, a formaldehyde-free phenolic resin using monosaccharide-based furfural was synthesized to act as the carbon precursor. One dimensional halloysite nanotube (HNT) with high porosity and excellent cation/anion exchange capacity was mixed with the phenol-furfural resin to fabricate carbonaceous nanocomposite HNT/C. Their structure and porosity were characterized. The effects of the halloysite nanotube amount and carbonization temperature on the electrochemical properties of HNT/C were explored. HNT/C exhibited rich porosity, involving a large specific surface area 253 m2·g-1 with a total pore volume of 0.27 cm3·g-1. The electrochemical performance of HNT/C was characterized in the three-electrode system and showed enhanced specific capacitance of 146 F·g-1 at 0.2 A g-1 (68 F·g-1 for pristine carbon) in electrolyte (6 mol·L-1 KOH) and a good rate capability of 62% at 3 A g-1. It also displayed excellent cycle performance with capacitance retention of 98.5% after 500 cycles. The symmetric supercapacitors with HNT/C-1:1.5-800 electrodes were fabricated, exhibiting a high energy density of 20.28 Wh·Kg-1 at a power density of 100 W·Kg-1 in 1 M Na2SO4 electrolyte. The present work provides a feasible method for preparing composite electrode materials with a porous structure from renewable phenol-furfural resin and HNT. The excellent supercapacitance highlights the potential applications of HNT/C in energy storage.

11.
Nanomaterials (Basel) ; 10(9)2020 Sep 16.
Artigo em Inglês | MEDLINE | ID: mdl-32947821

RESUMO

A series of Cu@Pd/C with different Pd contents was prepared using the galvanic reduction method to disperse Pd on the surface of Cu nanoparticles on Cu/C. The dispersion of Pd was regulated by the Cu(I) on the surface, which was introduced by pulse oxidation. The Cu2O did not react during the galvanic reduction process and restricted the Pd atoms to a specific area. The pulse oxidation method was demonstrated to be an effective process to control the oxidization degree of Cu on Cu/C and then to govern the dispersion of Pd. The catalysts were characterized by transmission electron microscopy (TEM), high-resolution transmission electron microscope (HRTEM), high angular annular dark field scanning TEM (HAADF-STEM), energy-dispersive spectroscopy (EDS) mapping, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), auger electron spectroscopy (AES), and inductively coupled plasma optical emission spectrometer (ICP-OES), which were used to catalyze the hydrogen evolution from ammonia borane. The Cu@Pd/C had much higher activity than the PdCu/C, which was prepared by the impregnation method. The TOF increased as the Cu2O in Cu/C used for the preparation of Cu@Pd/C increased, and the maximum TOF was 465 molH2 min-1 molPd-1 at 298 K on Cu@Pd0.5/C-640 (0.5 wt % of Pd, 640 mL of air was pulsed during the preparation of Cu/C-640). The activity could be maintained in five continuous processes, showing the strong stability of the catalysts.

12.
Pathog Dis ; 78(4)2020 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-32592396

RESUMO

The evidence of long-term clinical dynamic on Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) RNA re-positive case are less. We performed a 108 days follow-up on dynamic clinical presentations in a case, who hospitalized three times due to the positive recurrence of SARS-CoV-2 RNA after discharge, to understand the prognosis of the 2019-Coronavirus disease (COVID-19). In this case, positive SARS-CoV-2 recurred even after apparent recovery (normal CT imaging, no clinical symptoms, negative SARS-CoV-2 on stool sample and negative serum IgM test) from COVID-19, viral shedding duration lasted for 65 days, the time from symptom onset to disappearance was up to 95 days. Erythrocyte-associated indicators, liver function and serum lipid metabolism presented abnormal throughout during the observation period. Awareness of atypical presentations such as this one is important to prompt the improvement of the management of COVID-19.


Assuntos
Betacoronavirus/patogenicidade , Infecções por Coronavirus/sangue , Infecções por Coronavirus/virologia , Pneumonia Viral/sangue , Pneumonia Viral/virologia , RNA Viral/genética , Eliminação de Partículas Virais , Adulto , Alanina Transaminase/sangue , Antivirais/uso terapêutico , Aspartato Aminotransferases/sangue , Betacoronavirus/efeitos dos fármacos , Betacoronavirus/genética , Biomarcadores/sangue , COVID-19 , HDL-Colesterol/sangue , Infecções por Coronavirus/diagnóstico por imagem , Infecções por Coronavirus/tratamento farmacológico , Hospitalização , Humanos , Interferon alfa-2/uso terapêutico , Lopinavir/uso terapêutico , Masculino , Metilprednisolona/uso terapêutico , Pandemias , Pneumonia Viral/diagnóstico por imagem , Pneumonia Viral/tratamento farmacológico , RNA Viral/isolamento & purificação , Recidiva , SARS-CoV-2 , Tomografia Computadorizada por Raios X , gama-Glutamiltransferase/sangue
13.
Nanomaterials (Basel) ; 9(12)2019 Nov 28.
Artigo em Inglês | MEDLINE | ID: mdl-31795102

RESUMO

The hydrogenation of furan ring in the biomass-derived furans is of great importance for the conversion of biomass to valuable chemicals. Fabrication of high activity and selectivity catalyst for this hydrogenation under mild conditions was one of the focuses of this research. In this manuscript, UiO-66-v, in which vinyl bonded to the benzene ring, was first prepared. Then, the uniformly distributed vinyl was used as the reductant for the preparation of Pd/UiO-66-v. The catalyst was characterized by X-ray diffraction, thermogravimetric, N2 physical adsorption/desorption, X-ray photoelectron spectroscopy, scanning electron microscope, transmission electron microscopy, energy dispersive spectrometer elemental mappings, and inductively coupled plasma atomic emission spectroscopy to find the Pd/UiO-66-v had a narrow palladium nanoparticles size of 3-5 nm and maintained the structure and thermal stability of UiO-66-v. The Pd/UiO-66-v was used for the hydrogenation of furfuryl alcohol to tetrahydrofurfuryl alcohol in water. 99% conversion of furfuryl alcohol was obtained with 90% selectivity to tetrahydrofurfuryl alcohol after reacted at 0.5 MPa H2, 303 K for 12 h. The Pd/UiO-66-v was proved to be effective for the hydrogenation of furan ring in furans and could be used for at least five times.

14.
ACS Appl Mater Interfaces ; 11(47): 44430-44437, 2019 Nov 27.
Artigo em Inglês | MEDLINE | ID: mdl-31680508

RESUMO

PbS colloidal quantum dots passivated by the thiocyanate anion (SCN-) are developed to combine with perovskite (CH3NH3PbI3) as building blocks for UV-vis-NIR broadband photodetectors. Both high electrical conductivity and appropriate energy-level alignment are obtained by the in situ ligand exchange with SCN-. The PbS-SCN/CH3NH3PbI3 composite photodetectors are sensitive to a broad wavelength range covering the UV-vis-NIR region (365-1550 nm), possessing an excellent responsivity of 255 A W-1 at 365 nm and 1.58 A W-1 at 940 nm, remarkably high detectivity of 4.9 × 1013 Jones at 365 nm and 3.0 × 1011 Jones at 940 nm, and fast response time of ≤42 ms. Furthermore, a 10 × 10 photodetector array is fabricated and integrated, which constitutes a high-performance broadband image sensor. Our approach paves a way for the development of highly sensitive broadband photodetectors/imagers that can be easily integrated.

15.
ACS Appl Mater Interfaces ; 11(43): 40366-40371, 2019 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-31595743

RESUMO

Integration of selective photodetection and signal storage in a single device, such as organic field-effect transistor (OFET) memories, meets the demands for radiation monitoring and protection. A new strategy is developed to achieve filter-free and selective light monitoring by adopting a solution-processed blend charge-trapping layer in OFET memories, where the charge-trapping layer is composed of phenyl-C61-butyric acid methyl ester (PCBM) dispersed in a polymer electret thin film. The OFET memory without PCBM shows response only to ultraviolet light, whereas the spectral response edges are extended to the visible and near-infrared regions in the corresponding devices with relatively low and high contents of PCBM in the charge-trapping layer, respectively. A set of OFET memories with different PCBM contents is used to qualitatively evaluate the light composition in an optical source. The tunable spectral response in the OFET memories is ascribed to the additional photoassisted charge-trapping paths depending on the blend ratio in the charge-trapping layer. This mechanism may inspire alternative approaches to organic-based optical sensing and monitoring in flexible and wearable electronics.

16.
Adv Mater ; 30(44): e1804165, 2018 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-30247780

RESUMO

Metallic lithium (Li) is a promising anode for next-generation high-energy-density batteries, but its applications are still hampered due to the limited charging/discharging rate and poor cycling performance. Here, a hierarchical 3D porous architecture is designed with a binary network of continuous silver nanowires assembled on an interconnected 3D graphene skeleton as the host for Li-metal composite anodes, which offers a significant boost in both charging/discharging rates and long-term cycling performance for Li-metal batteries. This unique hierarchical binary network structure in conjunction with optimized material combination provides ultrafast, continuous, and smooth electron transportation channel and non-nucleation barrier sites to direct and confine Li deposition. It also offers outstanding mechanical strength and toughness to support massive Li deposition and buffer the internal stress fluctuations during long-term repeated Li stripping/plating thereby minimizing fundamental issues of dendrite formation and volume change even under ultrafast charging/discharging rates. As a result, the composite anode using this hierarchical host can work smoothly at an unprecedented high current density of 40 mA cm-2 over 1000 plating/stripping cycles with low overpotential (<120 mV) in symmetric cells. The as-constructed full cell, paired with LiNi0.5 Co0.2 Mn0.3 O2 cathode, also exhibits excellent rate capability and high-rate cycling stability.

17.
J Diabetes Investig ; 9(4): 741-752, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-29078040

RESUMO

AIMS/INTRODUCTION: Cell death-inducing DFF45-like effector C (CIDEC) was proven to be closely associated with the development of insulin resistance and metabolic syndrome. We aimed to investigate whether CIDEC gene silencing could alleviate pulmonary vascular remodeling in a type 2 diabetes rat model. MATERIALS AND METHODS: We built a type 2 diabetes rat model. An adenovirus harboring CIDEC small interfering ribonucleic acid was then injected into the jugular vein to silence the CIDEC gene. After hematoxylin-eosin and Sirius red staining, we detected indexes of the pulmonary arterioles remodeling. Immunohistochemical staining of proliferating cell nuclear antigen was used to evaluate the pulmonary arterial smooth muscle cell proliferation. Apoptosis was evaluated by terminal deoxynucleotidyl transferase dUTP nick end labeling reaction and western blotting. The levels of signaling pathway proteins expression were measured by western blotting analyses. RESULTS: Histological analysis of the pulmonary artery showed that the thickness of the adventitia and medial layer increased notably in type 2 diabetes rats. Immunohistochemistry showed that more proliferating cell nuclear antigen-positive pulmonary arterial smooth muscle cells could be seen in type 2 diabetes rats; and after CIDEC gene silencing, proliferating cell nuclear antigen positive cells decreased accordingly. Cleaved caspase-3 and cleaved poly (adenosine diphosphate-ribose) polymerase measured by western blotting showed increased apoptosis with overexpressed CIDEC in diabetes. Terminal deoxynucleotidyl transferase dUTP nick end labeling reaction showed that the apoptosis mainly occurred in endothelial cells. Western blotting analysis showed CIDEC overexpression in rats with diabetes, and phosphorylated adenosine 5' monophosphate-activated protein kinase-α expression was significantly decreased. After CIDEC gene silencing, the expression of phosphorylated adenosine 5' monophosphate-activated protein kinase-α was upregulated. CONCLUSIONS: The CIDEC/5' monophosphate-activated protein kinase signaling pathway could be a potential therapeutic candidate against pulmonary vascular diseases in type 2 diabetes patients.


Assuntos
Diabetes Mellitus Tipo 2/complicações , Diabetes Mellitus Tipo 2/genética , Proteínas/genética , Artéria Pulmonar/metabolismo , Remodelação Vascular/genética , Animais , Apoptose , Diabetes Mellitus Tipo 2/patologia , Modelos Animais de Doenças , Inativação Gênica , Pulmão/metabolismo , Masculino , Proteínas Quinases/metabolismo , Artéria Pulmonar/patologia , Ratos Sprague-Dawley , Transdução de Sinais
18.
RSC Adv ; 8(36): 20182-20189, 2018 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-35541635

RESUMO

Finding earth-abundant and high-performance electrode materials for supercapacitors is a demanding challenge in the energy storage field. Cuprous oxide (Cu2O) has attracted increasing attention due to its theoretically high specific capacitance, however, the development of Cu2O-based electrodes with superior capacitive performance is still challenging. We herein report a simple and effective ionic-liquid-assisted sputtering approach to synthesizing the Cu2O nanoparticles/multi-walled carbon nanotubes (Cu2O/MWCNTs) nanocomposite for high-performance asymmetric supercapacitors. The Cu2O/MWCNTs nanocomposite delivers a high specific capacitance of 357 F g-1, good rate capability and excellent capacitance retention of about 89% after 20 000 cycles at a current density of 10 A g-1. The high performance is attributed to the uniform dispersion of small-sized Cu2O nanoparticles on conductive MWCNTs, which offers plenty of redox active sites and thus improve the electron transfer efficiency. Oxygen vacancies are further introduced into Cu2O by the NaBH4 treatment, providing the oxygen-deficient Cu2O/MWCNTs (r-Cu2O/MWCNTs) nanocomposite with significantly improved specific capacitance (790 F g-1) and cycling stability (∼93% after 20 000 cycles). The assembled asymmetric supercapacitor based on the r-Cu2O/MWCNTs//activated carbon (AC) structure achieves a high energy density of 64.2 W h kg-1 at 825.3 W kg-1, and long cycling life. This work may form a foundation for the development of both high capacity and high energy density supercapacitors by showcasing the great potential of earth-abundant Cu-based electrode materials.

19.
ACS Appl Mater Interfaces ; 9(33): 27649-27656, 2017 Aug 23.
Artigo em Inglês | MEDLINE | ID: mdl-28758739

RESUMO

Flexible transparent solid-state supercapacitors have attracted immerse attention for the power supply of next-generation flexible "see-through" or "invisible" electronics. For fabrication of such devices, high-performance flexible transparent current collectors are highly desired. In this paper, the utilization of embedded Ag grid transparent conductive electrodes (TCEs) fabricated by a facile soft ultraviolet imprinting lithography method combined with scrap techniques, as the current collector for flexible transparent solid-state supercapacitors, is demonstrated. The embedded Ag grid TCEs exhibit not only excellent optoelectronic properties (RS ∼ 2.0 Ω sq-1 and T ∼ 89.74%) but also robust mechanical properties, which could meet the conductivity, transparency, and flexibility needs of current collectors for flexible transparent supercapacitors. The obtained supercapacitor exhibits large specific capacitance, long cycling life, high optical transparency (T ∼ 80.58% at 550 nm), high flexibility, and high stability. Owing to the embedded Ag grid TCE structure, the device shows a slight capacitance loss of 2.6% even after 1000 cycles of repetitive bending for a bending radius of up to 2.0 mm. This paves the way for developing high-performance current collectors and thus flexible transparent energy storage devices, and their general applicability opens up opportunities for flexible transparent electronics.

20.
Sci Rep ; 7(1): 6751, 2017 07 28.
Artigo em Inglês | MEDLINE | ID: mdl-28754899

RESUMO

Single-walled carbon nanotubes (SWCNTs) offer great potential for field-effect transistors and integrated circuit applications due to their extraordinary electrical properties. To date, as-made SWCNT transistors are usually p-type in air, and it still remains challenging for realizing n-type devices. Herein, we present efficient and reversible electron doping of semiconductor-enriched single-walled carbon nanotubes (s-SWCNTs) by firstly utilizing decamethylcobaltocene (DMC) deposited by a simple spin-coating process at room temperature as an electron donor. A n-type transistor behavior with high on current, large I on /I off ratio and excellent uniformity is obtained by surface charge transfer from the electron donor DMC to acceptor s-SWCNTs, which is further corroborated by the Raman spectra and the ab initio simulation results. The DMC dopant molecules could be reversibly removed by immersion in N, N-Dimethylformamide solvent, indicating its reversibility and providing another way to control the carrier concentration effectively as well as selective removal of surface dopants on demand. Furthermore, the n-type behaviors including threshold voltage, on current, field-effect mobility, contact resistances, etc. are well controllable by adjusting the surface doping concentration. This work paves the way to explore and obtain high-performance n-type nanotubes for future complementary CMOS circuit and system applications.

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