Supercapacitors are irreplaceable energy-storage devices for high power output and rapid charge/discharge of electrical energy. In this study, the laser-based fabrication of reduced graphene oxide (rGO) electrodes for supercapacitors is demonstrated with several new features of laser irradiation. A conventional CO2 laser irradiation system is equipped with (1) a nitrogen blower to avoid combustion of the GO paper, (2) a cylindrical lens for producing a wide line beam, and (3) an optical chopper system for generating an intensity-modulated laser beam. Scanning of the intensity-modulated line beam transforms an extended area of GO into chemically reduced and physically porous graphene. The effects of the laser beam modifications and scanning parameters on the electrochemical performance of the rGO electrode are investigated. The rGO electrode exhibits a high specific capacitance (up to ∼130 F/g) at a current density of 1 A/g. This work can serve as a reference for the process optimization of laser-induced G...
Abstract Direct reduction of graphene oxide has been regarded as the economically viable route for large-scale synthesis of graphene. However, the currently known methods suffer from either poor reduction efficiency or involve multi-step and energy-intensive reduction processes. Here, we demonstrate a remarkably fast, single step as well as highly efficient reduction technique to produce high-quality multilayer graphene film using a compact and low-cost CO 2 laser pyrolysis. Thanks to the intrin...
Abstract Graphene was prepared by excimer laser irradiation reduction of graphite oxide dissolved in an aqueous solution at different laser energies and irradiation time. The morphologies and structure of the laser reduced graphene were characterized using scanning electron microscopy, low angle X-ray diffraction (XRD) and X-ray photoelectron spectroscopy. The XRD results confirm that the deoxygenation of the graphite oxide sheets occurred almost completely for all laser irradiation conditions u...
Last. Y. Norman Zhou(THU: Tsinghua University)H-Index: 29
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Abstract High efficient fabrication of nanoscale surface structure has been achieved by line focusing a low repetition (1 kHz) femtosecond laser using a cylindrical lens. The results showed that this cylindrical lens increased fabrication rate by 10 times compared with a spherical lens. Both periodic ripple and random nanoparticle covered surface structures were obtained by optimizing the defocus distance and scanning speed. Strong time-dependent water contact angle (CA) was found in both laser ...
This article presents a new simple method of creating light-absorbing carbon material for optical devices such as bolometers. A simple method of laser microstructuring of graphene oxide is used in order to create such material. The absorption values of more than 98% in the visible and more than 90% in the infrared range are achieved. Moreover thermal properties of the films, such as temperature dependence and the thermal response of the samples, are studied. The change in resistance with tempera...
Abstract Photoreduction of graphene oxide (GO) to reduced graphene oxide (rGO) under ambient conditions was evaluated for three laser processing approaches: 800 nm fs pulses, 248 nm ns pulses, and 788 nm continuous wave (CW) illumination. Resultant features were compared using Raman, XPS, optical profilometry and SEM. The most effective approach for photoreduction and graphenization with minimal defects was nanosecond processing (0.12 J cm−2; 40 pulses overlapped). The Raman 2D band intensity co...
Abstract Indium tin oxide (ITO) films were prepared via a very simple and low-cost preparation technique based on a wet process using a continuous wave (CW) laser and an indium tin (In–Sn) alloy nanoparticle ink. The formation of continuous transparent conductive films using a laser sintering method and micropatterning of the ITO films using a laser direct writing method were investigated. This process is simpler than the conventional two-step heat treatment method and other wet processes that u...
For the past decade, researchers have been trying to understand the mechanism of the thermal reduction of graphite oxide. Because deuterium is widely used as a marker in various organic reactions, we wondered if deuterium-labeled graphite oxide could be the key to fully understand this mechanism. Graphite oxides were prepared by the Hofmann, Hummers, Staudenmaier, and Brodie methods, and a deuterium-labeled analogue was synthesized by the Hofmann method. All graphite oxides were analyzed not onl...
In this work, we demonstrate an environmentally benign and facile flash light irradiation process to reduce graphene oxide (GO). GO thin films were prepared by a vacuum filtration process, and these films were reduced by exposure to flash light irradiation for a few milliseconds at room temperature under ambient conditions. Flash light conditions such as energy, pulse width, and pulse number were varied to determine optimal conditions for this photothermal reduction of GO. The flash light irradi...
Abstract We demonstrate the fabrication of flexible micro-supercapacitors based on laser carbonization of polyimide sheets. Localized pulsed laser irradiation rapidly converts the pristine polyimide surface into an electrically conductive porous carbon structure in ambient conditions. Thus, the polyimide sheet acts as both a precursor for the carbonization and a flexible substrate. Effects of various laser parameters are examined to enhance electrical properties and morphology of the carbonized ...
#1Sanliang Zhang(UC Davis: University of California, Davis)H-Index: 6
#2Ning Pan(UC Davis: University of California, Davis)H-Index: 64
The performance of a supercapacitor can be characterized by a series of key parameters, including the cell capacitance, operating voltage, equivalent series resistance, power density, energy density, and time constant. To accurately measure these parameters, a variety of methods have been proposed and are used in academia and industry. As a result, some confusion has been caused due to the inconsistencies between different evaluation methods and practices. Such confusion hinders effective commun...
#1Shih-Feng Tseng(NTUT: National Taipei University of Technology)
#2Chen-Tang Chao(NTUT: National Taipei University of Technology)
Abstract null null A single-step reduction and patterning technique that involves high-pulse nanosecond fiber laser irradiation was used to reduce graphene oxide films (GOFs) for use in ceramic-based heaters. Laser reduction of GOFs was performed at a laser power, scan speed, pulse repetition frequency, and laser scan pitch of 2.2–4.1 W, 150–500 mm/s, 750 kHz, and 10 μm, respectively. The optimal intensity ratios of the D to G band (RD/G) and the 2D to G band (R2D/G) of reduced GOFs (RGOFs), obt...
#1Aya Hamed(E-JUST: Egypt-Japan University of Science and Technology)H-Index: 6
#2Amr Hessein(E-JUST: Egypt-Japan University of Science and Technology)H-Index: 3
Last. Ahmed Abd El-Moneim(E-JUST: Egypt-Japan University of Science and Technology)H-Index: 18
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Abstract A novel, scalable, single-step and low-synthesis temperature fabrication approach is proposed for real-time doping, reduction, and patterning of graphene oxide-based films supported on flexible polyethylene terephthalate (PET) substrate using a CO2 Laser system. Laser reduced graphene oxide (LrGO), nitrogen-doped laser reduced graphene oxide (N-LrGO), and sulfur-nitrogen co-doped laser reduced graphene oxide (SN-LrGO) planar supercapacitors (PSCs) are readily fabricated with the propose...
#1Cheng Peng(Hefei University of Technology)H-Index: 2
#2Qiang Li(Hefei University of Technology)H-Index: 11
Last. Yanwu Zhu(USTC: University of Science and Technology of China)H-Index: 69
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Abstract The development of portable and wearable electronic devices continues to increase the demand for miniature energy storage units. Here, we fabricate the flexible micro-supercapacitors (MSCs) through direct heating pattern on graphene oxide film. The shape designable MSCs are based on planar reduced graphene oxide/graphene oxide (rGO/GO) structure, with rGO as electrode and GO as separator. The GO area heated by heating pen is reduced to rGO, and the area with no heating is still GO. The ...
This paper deals with recent progress in the use of laser-induced graphene sensors for the electrochemical detection of glucose molecules. The exponential increase in the exploitation of the laser induction technique to generate porous graphene from polymeric and other naturally occurring materials has provided a podium for researchers to fabricate flexible sensors with high dynamicity. These sensors have been employed largely for electrochemical applications due to their distinct advantages lik...
Supercapacitors are being increasingly used as energy storage systems. Graphene, with its huge specific surface area, superior mechanical flexibility and outstanding electrical properties, constitutes an ideal candidate for the next generation of wearable and portable devices with enhanced performance. Since Stoller described the first graphene supercapacitor in 2008, significant developments have been made during this last decade in the development of new graphene-based electrodes. In this way,...
Fiber supercapacitors (SCs) are potential and promising candidates for the development of wearable lightweight energy storage units. Thus, investigations have been conducted on various aspects such as electrode materials and device configuration to enhance their performance. The representative types of fiber SC configurations are characterized by certain limitations, including the imprecise assembling process and increased resistance of the SCs. To address these limitations, herein, we report a ...
#1Rui Xuan(CAS: Chinese Academy of Sciences)H-Index: 1
#2Jinhui Li(CAS: Chinese Academy of Sciences)H-Index: 69
Last. Ching-Ping Wong(Georgia Institute of Technology)H-Index: 111
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Abstract With the continuous development of flexible electronic devices, the corresponding demands for electrochemical storage devices with flexibility and self-healing properties have been raised. However, the current supercapacitors still have great limitations in mechanical and self-healing performance. Herein, flexible and self-healing poly (2-acrylamido-2-methyl-1-propanesulfonic acid) (PAMPSA)/polyvinylimidazole (PVI)/LiCl polyelectrolyte is easily fabricated by a one-step copolymerization...
Abstract Laser direct writing technique has demonstrated its potentiality in producing high performance microsupercapacitors via beam scanning, which processes and patterns active substance simultaneously to form electrode features with high spatial resolution and accuracy. This method can process carbon, graphene and derived materials, and polymer to construct 3D porous graphene, hierarchical porous frames, and nanostructures with a precisely controlled porosity. This facilitates the absorption...
#1Qiang Li(HIT: Harbin Institute of Technology)H-Index: 109
#2Ding Ye(HIT: Harbin Institute of Technology)H-Index: 5
Last. Yang Wang(HIT: Harbin Institute of Technology)H-Index: 29
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Abstract Reduction and patterning of graphene oxide (GO) have been extensively applied in the field of electronic devices such as sensor, transistors and power source. Surface morphology and reduction level of reduced graphene oxide (rGO) directly influence the performance of devices. Herein, we put forward a new method of one-step periodic nanopatterning and reduction of GO using femtosecond laser pulses in air environment. Three-dimensional (3D) laser induced periodic surface structures (LIPSS...
The rapid repair of graphene oxide (GO) was demonstrated using a microwave cavity resonator that separates pure electric and magnetic fields from microwaves. Reduced graphene oxide (rGO), a high-quality graphene-like material, was obtained using our method. Raman spectroscopy of rGO after microwave treatment revealed that the D band intensity decreased as the temperature increased, while the G and G′ band intensities increased with increasing temperature. Furthermore, the cavity resonator provid...