| 1. |
- Fazi, Andrea, 1992, et al.
(författare)
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Multiple growth of graphene from a pre-dissolved carbon source
- 2020
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Ingår i: Nanotechnology. - : IOP Publishing. - 1361-6528 .- 0957-4484. ; 31:34, s. 345601-
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Tidskriftsartikel (refereegranskat)abstract
- Mono- to few-layer graphene materials are successfully synthesized multiple times using Cu-Ni alloy as a catalyst after a single-chemical vapor deposition (CVD) process. The multiple synthesis is realized by extracting carbon source pre-dissolved in the catalyst substrate. Firstly, graphene is grown by the CVD method on Cu-Ni catalyst substrates. Secondly, the same Cu-Nicatalyst foils are annealed, in absence of any external carbon precursor, to grow graphene using the carbon atoms pre-dissolved in the catalyst during the CVD process. This annealing process is repeated to synthesize graphene successfully until carbon is exhausted in the Cu-Ni foils. After the CVD growth and each annealing growth process, the as-grown graphene is removed using a bubbling transfer method. A wide range of characterizations are performed to examine the quality of the obtained graphene material and to monitor the carbon concentration in the catalyst substrates. Results show that graphene from each annealing growth process possesses a similar quality, which confirmed the good reproducibility of the method. This technique brings great freedom to graphene growth and applications, and it could be also used for other 2D material synthesis.
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| 2. |
- Fu, Yifeng, 1984, et al.
(författare)
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Graphene related materials for thermal management
- 2020
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Ingår i: 2D Materials. - : IOP Publishing. - 2053-1583. ; 7:1
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Tidskriftsartikel (refereegranskat)abstract
- Almost 15 years have gone ever since the discovery of graphene as a single atom layer. Numerous papers have been published to demonstrate its high electron mobility, excellent thermal and mechanical as well as optical properties. We have recently seen more and more applications towards using graphene in commercial products. This paper is an attempt to review and summarize the current status of the research of the thermal properties of graphene and other 2D based materials including the manufacturing and characterization techniques and their applications, especially in electronics and power modules. It is obvious from the review that graphene has penetrated the market and gets more and more applications in commercial electronics thermal management context. In the paper, we also made a critical analysis of how mature the manufacturing processes are; what are the accuracies and challenges with the various characterization techniques and what are the remaining questions and issues left before we see further more applications in this exciting and fascinating field.
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| 3. |
- Hansson, Josef, 1991, et al.
(författare)
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Effects of high temperature treatment of carbon nanotube arrays on graphite : Increased crystallinity, anchoring and inter-tube bonding
- 2020
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Ingår i: Nanotechnology. - : Institute of Physics Publishing (IOPP). - 0957-4484 .- 1361-6528. ; 31:45
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Tidskriftsartikel (refereegranskat)abstract
- Thermal treatment of carbon nanotubes (CNTs) can significantly improve their mechanical, electrical and thermal properties due to reduced defects and increased crystallinity. In this work we investigate the effect of annealing at 3000 degrees C of vertically aligned CNT arrays synthesized by chemical vapor deposition (CVD) on graphite. Raman measurements show a drastically reduced amount of defects and, together with transmission electron microscope (TEM) diffraction measurements, an increased average crystallite size of around 50%, which corresponds to a 124% increase in Young's modulus. We also find a tendency for CNTs to bond to each other with van der Waals (vdW) forces, which causes individual CNTs to closely align with each other. This bonding causes a densification effect on the entire CNT array, which appears at temperatures >1000 degrees C. The densification onset temperature corresponds to the thermal decomposition of oxygen containing functional groups, which otherwise prevents close enough contact for vdW bonding. Finally, the remaining CVD catalyst on the bottom of the CNT array is evaporated during annealing, enabling direct anchoring of the CNTs to the underlying graphite substrate.
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| 4. |
- Liu, Ya, 1991, et al.
(författare)
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Graphene based thermal management system for battery cooling in electric vehicles
- 2020
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Ingår i: Proceedings - 2020 IEEE 8th Electronics System-Integration Technology Conference, ESTC 2020.
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Konferensbidrag (refereegranskat)abstract
- In this work, a graphene assembled film integrated heat sink and water cooling technology was used to build an experimental set-up of a thermal management system to demonstrate the possibility to achieve efficient cooling of the propulsion battery in electric vehicles. The experimental results showed that the temperature decrease of a Li-ion battery module can reach 11°C and 9 °C under discharge rates as of 2C and 1C, respectively. The calculated thermal resistance of the graphene based cooling system is about 76% of a similar copper based cooling system. Surface modification was carried out on the graphene sheet to achieve a reliable bonding between the graphene sheet and the battery cell surface. This work provides a proof of concept of a new highly efficient approach for electric vehicle battery thermal management using the light-weight material graphene.
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| 5. |
- Sun, Peng, et al.
(författare)
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Scalable three-dimensional Ni 3 P-based composite networks for flexible asymmertric supercapacitors
- 2020
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Ingår i: Chemical Engineering Journal. - : Elsevier BV. - 1385-8947. ; 380
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Tidskriftsartikel (refereegranskat)abstract
- Flexible energy storage devices are of great importance in future wearable electronics. To achieve the popularization of these flexible equipments, it is urgent to develop proper productive method for easily scaling up high performance flexible electrode materials. Herein, a three-dimensional nano-network composite material based on Ni3P is designed on flexible carbon felt (CF). The network induced by the introduction of sulfonated polystyrene combines advantages of excellent redox ability of the Ni3P, great conductivity of NiCo alloy and fast electric double layer contribution of carbon. It shows a great energy storage performance and an excellent balance between areal and gravimetric capacitance (1.76 F cm−2 and 1048 F g−1), which are beneficial to the actual application. Besides, this CF@NiCoNiPC can be easily produced in a large-scale due to the simple and low-cost synthetic method. The CF@NiCoNiPC can be further fabricated into an asymmetric supercapacitor (ASC), which demonstrates an excellent capacitance of 516.7 mF cm−2 (170.5 F g−1) and long-term stability of 25,000 charging and discharging cycles (83% retentions). Excitingly, the ASC presents good mechanical performance with 92% capacitance retention after 1000 bending cycles. Three tandem ASCs can easily power a red LED for several minutes when charged for only 20 s even under a bent state, indicating the great potential in future flexible energy storage devices.
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| 6. |
- Zehri, Abdelhafid, 1989, et al.
(författare)
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High porosity and light weight graphene foam heat sink and phase change material container for thermal management
- 2020
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Ingår i: Nanotechnology. - : IOP Publishing. - 1361-6528 .- 0957-4484. ; 31:42
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Tidskriftsartikel (refereegranskat)abstract
- During the last decade, graphene foam emerged as a promising high porosity 3-dimensional (3D) structure for various applications. More specifically, it has attracted significant interest as a solution for thermal management in electronics. In this study, we investigate the possibility to use such porous materials as a heat sink and a container for a phase change material (PCM). Graphene foam (GF) was produced using chemical vapor deposition (CVD) process and attached to a thermal test chip using sintered silver nanoparticles (Ag NPs). The thermal conductivity of the graphene foam reached 1.3 W m(-1)K(-1), while the addition of Ag as a graphene foam silver composite (GF/Ag) enhanced further its effective thermal conductivity by 54%. Comparatively to nickel foam, GF and GF/Ag showed lower junction temperatures thanks to higher effective thermal conductivity and a better contact. A finite element model was developed to simulate the fluid flow through the foam structure model and showed a positive and a non-negligible contributions of the secondary microchannel within the graphene foam. A ratio of 15 times was found between the convective heat flux within the primary and secondary microchannel. Our paper successfully demonstrates the possibility of using such 3D porous material as a PCM container and heat sink and highlight the advantage of using the carbon-based high porosity material to take advantage of its additional secondary porosity.
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| 7. |
- Zhao, Changhong, 1982, et al.
(författare)
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Synthesis of graphene quantum dots and their applications in drug delivery
- 2020
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Ingår i: Journal of Nanobiotechnology. - : Springer Science and Business Media LLC. - 1477-3155. ; 18:1
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Forskningsöversikt (refereegranskat)abstract
- This review focuses on the recent advances in the synthesis of graphene quantum dots (GQDs) and their applications in drug delivery. To give a brief understanding about the preparation of GQDs, recent advances in methods of GQDs synthesis are first presented. Afterwards, various drug delivery-release modes of GQDs-based drug delivery systems such as EPR-pH delivery-release mode, ligand-pH delivery-release mode, EPR-Photothermal delivery-Release mode, and Core/Shell-photothermal/magnetic thermal delivery-release mode are reviewed. Finally, the current challenges and the prospective application of GQDs in drug delivery are discussed.[Figure not available: see fulltext.]
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