scholarly journals Investigation of Electrical Properties and Reliability of GaN-Based Micro-LEDs

Nanomaterials ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 689
Author(s):  
Ke Zhang ◽  
Yibo Liu ◽  
Hoi-sing Kwok ◽  
Zhaojun Liu
Keyword(s):  
Current Density ◽  
High Performance ◽  
High Current Density ◽  
Extreme Environments ◽  
Forward Voltage ◽  
Sapphire Substrates ◽  
Forward Current ◽  
Specific Analysis ◽  
Comparable Performance ◽  
Injection Current Density

In this paper, we report high-performance Micro-LEDs on sapphire substrates, with pixel size scaling to 20 µm and an ultra-high current density of 9902 A/cm2. The forward voltages (VF) of the devices ranged from 2.32 V to 2.39 V under an injection current density of 10 A/cm2. The size and structure-dependent effects were subsequently investigated to optimize the device design. The reliability of Micro-LED devices was evaluated under long-aging, high-temperature, and high-humidity conditions. It was found that Micro-LED devices can maintain comparable performance with an emission wavelength of about 445 nm and a full width at half maximum (FWHM) of 22 nm under extreme environments. Following this, specific analysis with four detailed factors of forward voltage, forward current, slope, and leakage current was carried out in order to show the influence of the different environments on different aspects of the devices.

Hydrothermal synthesis MoO3@CoMoO4 hybrid as an anode material for high performance lithium rechargeable batteries

2019 ◽  
Vol 12 (01) ◽  
pp. 1850104 ◽  
Author(s):  
Jinggao Wu ◽  
Qi Lai ◽  
Canyu Zhong
Keyword(s):  
Current Density ◽  
High Performance ◽  
High Current Density ◽  
Rate Capability ◽  
Lithium Ion ◽  
Charge Transfer Resistance ◽  
Rechargeable Batteries ◽  
Transfer Resistance ◽  
Lithium Rechargeable Batteries ◽  
One Step

MoO3@CoMoO4 hybrid is fabricated by a facile one-step hydrothermal method and is used as anode for lithium-ion battery (LIB). Compared to pristine MoO3, galvanostatic charge–discharge tests show that the hybrid electrode delivered a remarkable rate capability of 586.69[Formula: see text]mAh[Formula: see text]g[Formula: see text] at the high current density of 1000[Formula: see text]mA[Formula: see text]g[Formula: see text] and a greatly enhanced cyclic capacity of 887.36[Formula: see text]mA[Formula: see text]h[Formula: see text]g[Formula: see text] after 140 cycles at the current density of 200[Formula: see text]mA[Formula: see text]g[Formula: see text] (with capacity retention, 85.3%). The superior electrochemical properties could be ascribed to the synergistic effect of MoO3 and CoO nanostructure that results in the lower charge transfer resistance and the higher Li[Formula: see text] diffusion coefficient, thus leading to high performance Li[Formula: see text] reversibility storage.

Simplified Synthesis of 3D Flexible Reduced Graphene Oxide-Wrapped NiCo2O4 Nanowires for High-Performance Supercapacitor

2018 ◽  
Vol 10 (3) ◽  
pp. 358-364 ◽  
Author(s):  
Chao Pan ◽  
Hongyu Sun ◽  
Jingyi Gao ◽  
Yucai Hu ◽  
Jing Wang
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Current Density ◽  
Photoelectron Spectroscopy ◽  
High Performance ◽  
High Current Density ◽  
Three Dimensional ◽  
Simple Method ◽  
X Ray ◽  
Reduced Graphene

We introduced a simple method to construct novel three-dimensional (3D) flexible hierarchical nanocomposites by combining (1D) NiCo2O4 nanowires with 2D reduced graphene oxide (rGO) sheets. The hierarchical nanocomposite structure of rGO-wrapped NiCo2O4 (rGO-NiCo2O4) was confirmed by X-ray diffraction (XRD), Raman spectra, scanning electron microscopy (SEM), transmission electron microscope (TEM), and X-ray photoelectron spectroscopy (XPS). The results indicated that NiCo2O4 nanowires were successfully wrapped in rGO and the morphology of the rGO-NiCo2O4 showed a three-dimensional porous structure with NiCo2O4 being homogeneously distributed in the rGO. Given their apparent advantages, these two different nanostructures were evaluated as electrodes for high-performance supercapacitors. These electrodes exhibited a high capacitance of 1824.8 F·g–1 at a current density of 0.5 A·g–1, and an excellent cycling performance extending to 5000 cycles at a high current density of 4 A·g–1. Our results clearly demonstrate that rGO sheets on NiCo2O4 nanowires can substantially improve the capacitive performance of materials and ultimately increase the cycling stability of supercapacitors. The hierarchical binary nanocomposites show excellent electrochemical properties for energy storage applications, evidencing their potential application as supercapacitors.

An extremely low Pt loading cathode for a highly efficient proton exchange membrane water electrolyzer

Nanoscale ◽  
2017 ◽  
Vol 9 (48) ◽  
pp. 19045-19049 ◽  
Author(s):  
Hoyoung Kim ◽  
Seunghoe Choe ◽  
Hyanjoo Park ◽  
Jong Hyun Jang ◽  
Sang Hyun Ahn ◽  
...  
Keyword(s):  
Mass Transfer ◽  
Current Density ◽  
High Performance ◽  
Proton Exchange Membrane ◽  
High Current Density ◽  
Proton Exchange ◽  
The Self ◽  
High Current ◽  
Low Pt Loading ◽  
Exchange Membrane

The self-terminated electrodeposition (SED) of a Pt cathode with enhanced mass transfer demonstrates high performance of PEMWEs at high current density.

scholarly journals Sodium Dodecylbenzene Sulfonate Assisted Electrodeposition of MnO2@C Electrode for High Performance Supercapacitor

2021 ◽  
Author(s):  
Yihan Shi ◽  
Ming Zhang ◽  
Junshan Zhao ◽  
Liu Zhang ◽  
Xumei Cui ◽  
...  
Keyword(s):  
Electrochemical Performance ◽  
Specific Capacitance ◽  
Current Density ◽  
High Performance ◽  
High Current Density ◽  
Nickel Foam ◽  
Chemical Vapor ◽  
Precursor Solution ◽  
Sodium Dodecylbenzene Sulfonate ◽  
Dodecylbenzene Sulfonate

Abstract In this work, MnO2&SDBS electrodes with nano-honeycomb morphology were prepared by ultrasound-assisted electrochemical deposition using sodium dodecylbenzene sulfonate (SDBS) as a surfactant agent. The effect and mechanism of SDBS on the morphology of MnO2 nanomaterials during the preparation of MnO2 by electrochemical anodic oxidation was systematically investigated by varying the content of SDBS in the precursor solution. When the SDBS concentration is 2 g\bulletL-1, the resulting electrode has the best electrochemical performance, and the specific capacitance is up to 407 F\bulletg-1 at the current density of 1000 mAg-1. To further enhance its performance, a carbon coating layer was deposited on the surface of the electrode using a method similar to chemical vapor deposition. Finally, the MnO2&SDBS@C electrode with a three-dimensional net-to-film composite structure with a high specific surface area, hierarchical structure and interconnect with nickel foam supports were obtained. The electrode has excellent electrochemical performance, and the specific capacitance is still up to 289 Fg-1 at a high current density of 5000 mAg-1. Furthermore, the specific capacitance of the electrode was maintained at 76.7% after 5000 cycles of charging and discharging at a current density of 2000 mAg−1.

scholarly journals N-Doped Carbon Boosted the Formation of Few-Layered MoS2 for High-Performance Lithium and Sodium Storage

2021 ◽  
Vol 8 ◽  
Author(s):  
Junfeng Li ◽  
Xianzi Zhou ◽  
Kai Lu ◽  
Chao Ma ◽  
Liang Li ◽  
...  
Keyword(s):  
Current Density ◽  
High Performance ◽  
High Current Density ◽  
Low Cost ◽  
Lithium Ion ◽  
Reversible Capacity ◽  
Molybdenum Sulfide ◽  
High Current ◽  
High Theoretical Capacity ◽  
Sodium Storage

Molybdenum sulfide (MoS2) has become a potential anode of lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs) due to its high theoretical capacity and low cost. However, the volume expansion, poor electrical conductivity and dissolution of polysulfides in the electrolyte during the cycling process severely limited its applications. Herein, few-layered MoS2@N-doped carbon (F-MoS2@NC) was synthesized through a facile solvothermal and annealing process. It was found that the addition of N-doped carbon precursor could significantly promote the formation of few-layered MoS2 and improve the performances of lithium and sodium storage. A high reversible capacity of 482.6 mA h g−1 at a high current density of 2000 mA g−1 could be obtained for LIBs. When used as anode material for SIBs, F-MoS2@NC hybrids could maintain a reversible capacity of 171 mA h g−1 at a high current density of 1,000 mA g−1 after 600 cycles. This work should provide new insights into carbon hybrid anode materials for both LIBs and SIBs.

scholarly journals Hierarchical Porous Carbon Derived from Sichuan Pepper for High-Performance Symmetric Supercapacitor with Decent Rate Capability and Cycling Stability

Nanomaterials ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 553 ◽  
Author(s):  
Hengshuo Zhang ◽  
Wei Xiao ◽  
Wenjie Zhou ◽  
Shanyong Chen ◽  
Yanhua Zhang
Keyword(s):  
Specific Capacitance ◽  
Current Density ◽  
High Performance ◽  
High Current Density ◽  
Rate Capability ◽  
Cycling Stability ◽  
Koh Activation ◽  
High Current ◽  
Symmetric Supercapacitor ◽  
Hierarchical Porous

Hierarchical micro-mesoporous carbon (denoted as HPC-2 in this study) was synthesized by pre-carbonization of biomass Sichuan pepper followed by KOH activation. It possessed well-developed porosity with the specific surface area of 1823.1 m2 g−1 and pore volume of 0.906 cm3 g−1, and exhibited impressive supercapacitive behaviors. For example, the largest specific capacitance of HPC-2 was tested to be ca. 171 F g−1 in a three-electrode setup with outstanding rate capability and stable electrochemical property, whose capacitance retention was near 100% after cycling at rather a high current density of 40 A g−1 for up to 10,000 cycles. Furthermore, a two-electrode symmetric supercapacitor cell of HPC-2//HPC-2 was constructed, which delivered the maximum specific capacitance and energy density of ca. 30 F g−1 and 4.2 Wh kg−1, respectively, had prominent rate performance and cycling stability with negligible capacitance decay after repetitive charge/discharge at a high current density of 10 A g−1 for over 10,000 cycles. Such electrochemical properties of HPC-2 in both three- and two-electrode systems are superior or comparable to those of a great number of porous biomass carbon reported previously, hence making it a promising candidate for the development of high-performance energy storage devices.

Low Temperature Thin-film Silicon Diodes for Consumer Electronics

2005 ◽  
Vol 862 ◽  
Author(s):  
Qi Wang ◽  
Scott Ward ◽  
Anna Duda ◽  
Jian Hua ◽  
Paul Stradins ◽  
...  
Keyword(s):  
Thin Film ◽  
Low Temperature ◽  
Current Density ◽  
Voltage Drop ◽  
High Current Density ◽  
Consumer Electronics ◽  
High Current ◽  
Plastic Substrates ◽  
Forward Current ◽  
Thin Film Silicon

AbstractWe have developed high current density thin-film silicon n-i-p diodes for low cost and low temperature two-dimensional diode-logic memory array applications. The diodes are fabricated at temperatures below 250°C on glass, stainless steel, and plastic substrates using hot-wire chemical vapor deposition (CVD). The 0.01-mm2 standalone diodes have a forward current-density (J) of near 10 kA/cm2 and a rectification ratio over 107 at ±2 V. The 25 μm2 array diodes have J > 104 A/cm2 and rectification of 105 at ±2V. On plastic substrates, we have also used plasma-enhanced CVD to deposit 10-μm diameter diodes with J ˜ 5 x 104 A/cm2. We found that the use of microcrystalline silicon (μc-Si) i- and nlayers results in higher current-density diodes than with amorphous silicon. Reducing the diode area increases the forward current density by lowering the voltage drop across the external series resistances. A prototype diode array memory based on 10-micron devices was successfully demonstrated by monolithically integrating diodes with a-Si:H switching elements. High current density diodes have potential applications in a variety of large area, thin-film electronic devices, in addition to a-Si:H-based memory. This could widen the application of thin-film silicon beyond its present industrial applications in thin-film transistors, solar cells, bolometers and photo-detectors.

Porous CuCo2O4 nanocubes wrapped by reduced graphene oxide as high-performance lithium-ion battery anodes

Nanoscale ◽  
2014 ◽  
Vol 6 (12) ◽  
pp. 6551-6556 ◽  
Author(s):  
Wenpei Kang ◽  
Yongbing Tang ◽  
Wenyue Li ◽  
Zhangpeng Li ◽  
Xia Yang ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Lithium Ion Battery ◽  
Reduced Graphene Oxide ◽  
Current Density ◽  
High Performance ◽  
High Current Density ◽  
Lithium Ion ◽  
High Current ◽  
Reduced Graphene ◽  
Graphene Oxide Sheets

Porous CuCo2O4 nanocubes well wrapped by reduced graphene oxide sheets were facilely prepared and they showed impressive performance at high current density as the anode material of a lithium ion battery.

scholarly journals Development and large volume production of extremely high current density YBa2Cu3O7 superconducting wires for fusion

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
A. Molodyk ◽  
S. Samoilenkov ◽  
A. Markelov ◽  
P. Degtyarenko ◽  
S. Lee ◽  
...  
Keyword(s):  
Magnetic Fields ◽  
Current Density ◽  
High Performance ◽  
Economies Of Scale ◽  
High Current Density ◽  
High Volume ◽  
Fourth Power ◽  
High Magnetic Fields ◽  
Ybco Superconductor ◽  
Very High

AbstractThe fusion power density produced in a tokamak is proportional to its magnetic field strength to the fourth power. Second-generation high temperature superconductor (2G HTS) wires demonstrate remarkable engineering current density (averaged over the full wire), JE, at very high magnetic fields, driving progress in fusion and other applications. The key challenge for HTS wires has been to offer an acceptable combination of high and consistent superconducting performance in high magnetic fields, high volume supply, and low price. Here we report a very high and reproducible JE in practical HTS wires based on a simple YBa2Cu3O7 (YBCO) superconductor formulation with Y2O3 nanoparticles, which have been delivered in just nine months to a commercial fusion customer in the largest-volume order the HTS industry has seen to date. We demonstrate a novel YBCO superconductor formulation without the c-axis correlated nano-columnar defects that are widely believed to be prerequisite for high in-field performance. The simplicity of this new formulation allows robust and scalable manufacturing, providing, for the first time, large volumes of consistently high performance wire, and the economies of scale necessary to lower HTS wire prices to a level acceptable for fusion and ultimately for the widespread commercial adoption of HTS.

Coralloid Au enables high-performance Zn-CO2 battery and self-driven CO production

2021 ◽  
Author(s):  
Sanshuang Gao ◽  
Mengmeng Jin ◽  
Jiaqiang Sun ◽  
Xijun Liu ◽  
Shusheng Zhang ◽  
...  
Keyword(s):  
Energy Consumption ◽  
Current Density ◽  
High Performance ◽  
Co2 Fixation ◽  
High Current Density ◽  
Low Energy ◽  
Co2 Conversion ◽  
High Current ◽  
Key Factors ◽  
Low Energy Consumption

The electrocatalytic CO2 conversion with high current density and low energy consumption are dimerous key factors for practical CO2 fixation. Herein, coralloid Au was prepared via a facile electrodeposition approach,...

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