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Synthesis of graphene oxide from used electrode graphite with controlled oxidation process
摘要： Graphene oxide and reduced graphene oxide attract a lot of attention due to graphene provides some properties that suitable for wider application. Properties of graphene are unique since it can be tuned regarding to its controlled synthesis method and several treatments. This work, graphene oxide was synthesized from used graphite electrode by modified Hummer’s method in which oxidation process controlled. Zinc was used to produce reduced graphene oxide. Graphene oxide and reduced graphene oxide were characterized by SEM, EDS, FT-IR, UV-vis, and XRD. Effective strategy was studied to produce graphene oxide and reduced graphene oxide by controlling its oxidation process. These results prove that chemical and structural properties of graphene oxide and reduced graphene oxide depend on oxidation duration. Furthermore, carbon/oxygen ratio was studied to evaluate effective oxidation process.
关键词： graphene oxide,reduced graphene oxide,used electrode graphite,modified Hummer’s method,controlled oxidation process
更新于2025-09-11 14:15:04
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Handbook of Graphene || Quantitative Real‐Time Evaluation of C/O Ratios and Stepwise Control of Deoxidization of Graphene Oxide Using Plasmonic‐Based Electrochemical Spectroscopy
摘要： Graphene oxide (GO) is composed of carbon and oxygen functional groups. It has been the subject of extensive research because these oxygen functional groups can be readily processed for various applications. A novel technique to deoxidize GO to reduced graphene oxide (rGO) sheets to enable the stepwise control of surface oxygen content and maximize the quality of carbon-based composites at low cost is needed. This chapter introduces new technology using the electrochemical (EC) technique of cyclic voltammetry to reduce GO, and shows that surface plasmon resonance (SPR) technology can be used to detect refractive index variations of dielectric materials near the metal surface while simultaneously using surface plasmon waves (SPWs) to detect the reduction of GO. It is important to understand the mechanisms of the atomic construction of GO surface oxygen-containing functional groups so that they can be developed in bulk for biosensor and optoelectronic applications. Directions for future research in the field of rGO film-based composites include increasing the stability of the electrodes, improving charge carrier mobility, tuning the dielectric layer and its optical band-gap properties, enhancing the binding interaction to improve the sensitivity of biosensors using the film, and modulating the SP resonance energy.
关键词： cyclic voltammetry (CV),reduced graphene oxide (rGO),Graphene oxide (GO),electrochemical surface plasmon resonance (EC-SPR)
更新于2025-09-11 14:15:04
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Functionalized and reduced graphene oxide as hole transport layer and for use in ternary organic solar cell
摘要： Here is reported the performance of organic solar cells (OSCs) by using a new graphene oxide derivative as hole transport layer (HTL). OSCs are based on the PTB7:PC71BM blend as active layer and the alternative top electrode Field’s metal (Bi/In/Sn: 32.5%, 51%, 16.5%), which can be easily deposited through a vacuum-free process at regular atmosphere and low temperature (90°C). Graphene oxide (GO) was chemically functionalized and reduced with pentafluorophenylhydrazine, this fluorinated reduced graphene oxide (F5-rGO) was suspended in dimethylformamide for easy deposit by wet techniques such as spin-cast. F5-rGO has a work-function of 5.1 eV due to the high electronegativity of fluorine atoms incorporated into the GO sheets. The best achieved PCE of the OSCs fabricated for a single layer of F5-rGO was 5.82%. An enhanced PCE of 7.67% when F5-GO was used as interlayer between ITO and PEDOT:PSS was reached (PCE of PEDOT:PSS-based was 7.29%). Additionally, functionalized and reduced (chemically) graphene oxide (H5-rGO) was also obtained from GO treated with phenylhydrazine, and ternary OSCs were also prepared by adding H5-rGO to the PTB7:PC71BM blend at different weight ratios: 0, 3, and 6%. The best results were achieved with 3% of H5-rGO: OSCs presented a PCE of 7.56%.
关键词： Functionalized-reduced graphene oxide,PTB7:PC71BM,Hole transport layer,Ternary OSCs,Organic solar cells
更新于2025-09-11 14:15:04
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Improving and Stabilizing Perovskite Solar Cells with Incorporation of Graphene in the Spiro-OMeTAD Layer: Suppressed Li Ions Migration and Improved Charge Extraction
摘要： Perovskite solar cells (PSCs) have achieved a huge success in power conversion efficiency (PCE), while they still suffer from the long-term stability problem caused by the intrinsic sensitivity of perovskites to moisture. 2,2’,7,7’-tetrakis (N, N-di-p-methoxyphenylamine) 9,9’-spirobifluorene (Spiro-OMeTAD) is widely used as the hole transport layer (HTL) in typical PSCs; meanwhile bis(trifuoromethane)sulfonimide lithium salt (Li-TFSI) proves its necessity as an additive in the Spiro-OMeTAD HTL to improve the hole mobility. However, the Li+ ions bring in high hygroscopicity and water-uptake effect that both aggravate degradation of the Spiro-OMeTAD HTL and thereby of the perovskite layers. Here, we modify the Li-TFSI-based Spiro-OMeTAD HTL by adding reduced graphene oxide (rGO). We verify that rGO provides adsorption sites for Li+ ions and subsequently suppresses Li+ migration. The water-uptake effect originated from Li+ ions is thus relieved and detestable pinholes in HTL caused by Li+ ion migration are eliminated. Consequently, the rGO-incorporated HTL remarkably improves the device stability that maintains the initial PCEs within 3% loss after 700 h under 40% humidity; whereas the pristine devices almost lose the efficiency after 620 h. In addition, the good conductivity of the rGO favors hole transport in the Spiro-OMeTAD, resulting in a promotion in PCEs from 17.7% to 19.3% by incorporating rGO in HTL. Our work takes an insight into the function of rGO in the HTL and demonstrates an effective way of improving the efficiency and stability of PSCs simultaneously.
关键词： Perovskite solar cells,lithium ions,moisture stability,reduced graphene oxide (rGO),charge extraction,ion migration
更新于2025-09-11 14:15:04
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[IEEE 2019 IEEE Photonics Conference (IPC) - San Antonio, TX, USA (2019.9.29-2019.10.3)] 2019 IEEE Photonics Conference (IPC) - Investigations on HI Reduced Graphene Based FET for Photon Detection
摘要： Reduced graphene oxide-based field effect transistor is fabricated and tested for detection of UV photons in 100-280 nm range. A novel technique is used for reduction of Graphene oxide. The fabricated device showed promising response to UV photons in terms of resistance change in rGO.
关键词： Reduced graphene oxide,UV photon detector,XRD,Field Effect Transistor,Raman spectroscopy
更新于2025-09-11 14:15:04
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Manipulated interparticle gaps of silver nanoparticles by dendron-exfoliated reduced graphene oxide nanohybrids for SERS detection
摘要： We have successfully prepared a floating-typed surface-enhanced Raman scattering (SERS) substrate by the uniform nanoparticle arrays of silver nanoparticles (AgNPs) immobilized on the dendron-exfoliated reduced graphene oxide (rGO) nanosheets. These poly(urea/malonamide) dendrons were precisely synthesized, and then grafted on the dendron-exfoliated rGO nanosheets based on an efficient building block of dual functional 4-isocyanato-4′-(3,3-dimethyl-2,4-dioxo-azetidino)-diphenylmethane (IDD). By using dendron-rGO nanosheets as templates for hosting AgNPs, the particle size (D) and interparticle gap (W) of AgNPs could be manipulated by the incorporation of dendrons of various generations (0.5, 1.5, and 2.5 generations), evaluated by transmission electron microscopy. The results indicate that the nanohybrids with 1.5 generation-dendron exhibited stable, enormous, and linear-quantitative Raman enhancement in malachite green detection (1–100 ppm), due to the lowest W/D ratio (0.85 ± 0.60) and interparticle gap (7.60 ± 5.29 nm). The limit of detection (LOD) of malachite green is lower than 2.7 × 10?11 M (0.01 ppb). AgNPs@rGO-dendritic derivative nanohybrids as floating and flexible SERS substrates provide ultrasensitive and stable SERS detection in the solutions, which offers great potential for practical applications in detecting environmental pollutants.
关键词： Silver nanoparticles,Reduced graphene oxide nanosheets,Surface-enhanced Raman scattering detection,Dendritic polymers
更新于2025-09-11 14:15:04
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Pd2+-conjugated reduced graphene oxide as a highly efficient visible-light-induced photocatalytic Suzuki-Miyaura coupling
摘要： In this work, we investigated Pd2+- and Pd0-loaded graphene oxide (GO) and reduced graphene oxide (r-GO) as water-soluble, visible-light-responsive photocatalysts for the Suzuki-Miyaura C-C coupling reaction. Nanosheets of r-GO (~ 200 nm) were found to be a more desirable substrate than GO nanosheets, since the corresponding catalyst showed higher activities than those of the GO catalysts in both the visible-light-induced and thermal-reactions. Furthermore, Pd2+-loaded GO and r-GO show higher catalytic activities than those of Pd0-loaded GO and r-GO because of the more efficient oxidative addition to Pd2+ compared with that to Pd0. Systematic studies under dark and light conditions demonstrated the synergic contributions of photoexcited electron transfer and the strong photothermal effect of r-GO. Pd2+- and Pd0-loaded r-GO show four-times higher photocatalytic activities compared to those of Pd0-MoS2 and Pd0-WS2 catalysts for the Suzuki-Miyaura C-C coupling reaction.
关键词： Suzuki-Miyaura coupling,reduced graphene oxide,Pd2+-conjugated reduced graphene oxide,graphene oxide,visible-light-induced photocatalytic
更新于2025-09-10 09:29:36
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Millimeter wave absorbing property of flexible graphene/acrylonitrile-butadiene rubber composite in 5G frequency band
摘要： The coming fifth generation mobile communication technology (5G) puts forward enormous requirements on millimeter wave (MMW) absorbing materials above 24 GHz. In the present work, elastic absorbing composites were fabricated with reduced graphene oxide (RGO) of different reduction time and nitrile rubber (NBR). A series of characterization methods were used to study the reduction degree and the structure of composites, the electromagnetic parameters of composites in 26.5–40 GHz were also measured and used to conduct an analytical computation of reflection loss (RL). It was found that, 3h-RGO/NBR presented the minimum RL of ?45 dB at 35.4 GHz while 7h-RGO/NBR exhibited the widest effective bandwidth (<-10 dB) about 6.5 GHz. In addition, the mechanical properties of composites were also improved by RGO. Therefore, the obtained RGO/NBR composites displayed promising prospect as elastic MMW absorbing materials for 5G applications.
关键词： 5G Frequency Band,reduced graphene oxide,Nitrile rubber,millimeter wave absorbing
更新于2025-09-10 09:29:36
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Iron ions doping enhanced electromagnetic wave absorption properties of tin dioxide/reduced graphene oxide nanocomposites
摘要： Herein, the iron ions doped tin dioxide/reduced graphene oxide (Fe-doped SnO2/RGO) nanocomposites were fabricated by a facile one-step hydrothermal strategy. The structure, composition, micromorphology, and electromagnetic parameters of the obtained nanocomposites were systematically investigated by various analysis techniques. Results revealed that the doping of Fe3+ ion had notable effect on the structure and electromagnetic wave (EMW) absorption properties of SnO2/RGO nanocomposites. The as-prepared Fe-doped SnO2/RGO nanocomposites showed the minimum reflection loss (RLmin) of ?29.0 dB and effective absorption bandwidth (EAB, RL ≤ ?10 dB) of 2.7 GHz. Significantly, the dual-waveband absorption characteristic almost covering the C and Ku bands was observed. Besides, the possible EMW absorption mechanism was further proposed. Our results could be helpful for the designing and developing novel graphene-based nanocomposites as the high-performance EMW absorbers.
关键词： Electromagnetic wave absorption,Doping,Tin dioxide,Reduced graphene oxide,Hydrothermal
更新于2025-09-10 09:29:36
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THE EFFECT OF VARIATION OF REACTIONAL PARAMETERS IN THE PREPARATION OF GRAPHENE BY OXIDATION AND REDUCTION OF GRAPHITE
摘要： This work shows the influence of several reactional parameters for obtaining graphene through successive steps of oxidation and exfoliation of bulk graphite (resulting in graphene oxide), followed by chemical reduction. The results showed that changes in temperature, reaction time, reducing agent and source of primary graphite lead to different surface compositions and stability in dispersion of graphene oxide. Also, the use of different reducing agents promoted different degrees of restoration of C=C bonds in the bidimensional structure of graphene.
关键词： reduced graphene oxide,graphene,graphene oxide
更新于2025-09-09 09:28:46