| 1. |
- Liu, Ya, 1991, et al.
(författare)
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Egg albumen templated graphene foams for high-performance supercapacitor electrodes and electrochemical sensors
- 2018
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Ingår i: Journal of Materials Chemistry A. - : Royal Society of Chemistry (RSC). - 2050-7488 .- 2050-7496. ; 6:37, s. 18267-18275
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Tidskriftsartikel (refereegranskat)abstract
- We demonstrate a simple and scalable strategy to obtain N, S and Si co-doped biocompatible graphene foams (GFs) with different shapes using egg albumen as the template. The unique porous structure and element doping endow the GFs with a high charge-discharge rate and good wettability, which largely improve the electrochemical performance of the electrodes, including ultrahigh specific capacitance (534 F g-1at 1 A g-1), and excellent rate capability (308 F g-1at 100 A g-1) and cycling performance (96.1% retention of the initial capacitance after 10000 cycles at a high current density of 10 A g-1). Besides, when used as an electrochemical sensor for dopamine, the GF exhibits a detection limit as low as 1.2 μM with a linear response up to 70 μM, due to the low equivalent series resistance. These reveal great potential for promoting the application of 3D graphene in energy storage and electrochemical sensors.
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| 2. |
- Banerjee, Debashree, et al.
(författare)
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Elevated thermoelectric figure of merit of n-type amorphous silicon by efficient electrical doping process
- 2018
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Ingår i: Nano Energy. - : Elsevier BV. - 2211-2855 .- 2211-3282. ; 44, s. 89-94
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Tidskriftsartikel (refereegranskat)abstract
- The currently dominant thermoelectric (TE) materials used in low to medium temperature range contain Tellurium that is rare and mild-toxic. Silicon is earth abundant and environment friendly, but it is characterized by a poor TE efficiency with a low figure of merit, ZT. In this work, we report that ZT of amorphous silicon (a-Si) thin films can be enhanced by 7 orders of magnitude, reaching ∼0.64 ± 0.13 at room temperature, by means of arsenic ion implantation followed by low-temperature dopant activation. The dopant introduction employed represents a highly controllable doping technique used in standard silicon technology. It is found that the significant enhancement of ZT achieved is primarily due to a significant improvement of electrical conductivity by doping without crystallization so as to maintain the thermal conductivity and Seebeck coefficient at the level determined by the amorphous state of the silicon films. Our results open up a new route towards enabling a-Si as a prominent TE material for cost-efficient and environment-friendly TE applications at room temperature.
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| 3. |
- Casa, Marcello, et al.
(författare)
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Conductive adhesive based on mussel-inspired graphene decoration with silver nanoparticles
- 2018
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Ingår i: Journal of Nanoscience and Nanotechnology. - : American Scientific Publishers. - 1533-4880. ; 18:2, s. 1176-1185
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Tidskriftsartikel (refereegranskat)abstract
- Decoration with silver nanoparticles was obtained by coating graphene with a polydopamine layer, able to induce spontaneous metallic nanoparticles formation without any specific chemical interfacial modifier, neither using complex instrumentation. The choice of dopamine was inspired by the composition of adhesive proteins in mussels, related to their robust attach to solid surfaces. The synthesis procedure started from graphite and involved eco-friendly compounds, such as Vitamin C and glucose as reducing agent and water as reaction medium. Silver decorated graphene was inserted as secondary nanofiller in the formulation of a reference conductive adhesive based on epoxy resin and silver flakes. A wide characterization of the intermediate materials obtained along the step procedure for the adhesive preparation was carried out by several techniques. We have found that the presence of nanofiller yields, in addition to an improvement of the thermal conductivity (up to 7.6 W/m· K), a dramatic enhancement of the electrical conductivity of the adhesive. In particular, starting from 3 · 10 2 S/cm of the reference adhesive, we obtained a value of 4 · 10 4 S/cm at a nanofiller concentration of 11.5 wt%. The combined double filler conductivity was evaluated by Zallen’s model. The effect of the temperature on the resistivity of the adhesive has been also studied.
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| 4. |
- Hansson, Josef, 1991, et al.
(författare)
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Novel nanostructured thermal interface materials: a review
- 2018
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Ingår i: International Materials Reviews. - : Informa UK Limited. - 0950-6608 .- 1743-2804. ; 63:1, s. 22-45
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Forskningsöversikt (refereegranskat)abstract
- The trend of continuing miniaturisation of microelectronics leads to new thermal management challenges. A key point in the heat removal process development is to improve the heat conduction across interfaces through improved thermal interface materials (TIMs). We identify the key areas for state-of-the art TIM research and investigate the current state of the field together with possible future advances.
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| 5. |
- Hansson, Josef, 1991, et al.
(författare)
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Synthesis of a Graphene Carbon Nanotube Hybrid Film by Joule Self-heating CVD for Thermal Applications
- 2018
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Ingår i: Proceedings - Electronic Components and Technology Conference. - 0569-5503.
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Konferensbidrag (refereegranskat)abstract
- Hybrid films based on vertically aligned carbon nanotubes (CNTs) on graphene or graphite sheets have been proposed for application as thermal interface materials and micro heat sinks. However, the fabrication of these materials are limited to small scale, expensive and complicated chemical vapor deposition (CVD) for CNT synthesis. We present a new method for direct growth of CNTs on one or both sides of a thin graphene film (GF) using joule self-heating of the graphene film to provide the necessary heat for the thermal breakdown of carbon feedstock in a CVD process. The resulting CNT forests show good density and alignment consistent with regular CVD synthesis processes on silicon surfaces. The resulting double sided GF/CNT hybrid film is directly applicable as a thermal pad. The CNT forest has a thermal conductivity of 30 W/mK, measured by pulsed photothermal reflectance, and the total thermal interface resistance between aluminum blocks was measured to be 60 Kmm 2 /W using an ASTM D5470 compliant 1-D measurement setup. This method of directly synthesizing CNTs on graphene films is more energy efficient and capable of larger volume production compared to traditional CVD methods. It is also compatible with scaling up towards continuous roll-to-roll production for large scale commercial production, one of the major limitations preventing CVD-grown CNTs from commercial applications
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| 6. |
- Kabiri Samani, Majid, 1976, et al.
(författare)
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Improving Thermal Transport at Carbon Hybrid Interfaces by Covalent Bonds
- 2018
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Ingår i: Advanced Materials Interfaces. - : Wiley. - 2196-7350. ; 2018:5
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Tidskriftsartikel (refereegranskat)abstract
- Graphene and carbon nanotubes have received much attention for thermal management application due to their unique thermal performance. Theoretical work suggests that a covalent bond can combine 1D carbon nanotubes with 2D graphene together to extend the excellent thermal property to three dimensions for heat dissipation. This paper experimentally demonstrates the high heat dissipation capability of a freestanding 3D multiwall carbon nanotube (MWCNT) and graphene hybrid material. Using high-resolution transmission electron microscopy and pulsed photothermal reflection measurement method, the covalent bonds between MWCNT and planar graphene are microscopically and numerically demonstrated. Thermal resistance at the junction with covalent bonds is 9×10^−10 Kelvin square meter per watt, which is three orders of magnitude lower than van der Waals contact. Joule heating method is used to verify the extra cooling effect of this 3D hybrid material compared to graphite film. A demonstrator using high power chip is developed to demonstrate the applicability of this hybrid material in thermal application. Temperature at hot spots can be decreased by around 10°C with the assistance of this hybrid material. These findings are very significant for understanding the thermal conduction during combining 1D and 2D carbon material together for future thermal management application.
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| 7. |
- Lin, Rui, et al.
(författare)
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Real-time 100 Gbps/lambda/core NRZ and EDB IM/DD Transmission over 10 km Multicore Fiber
- 2018
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Ingår i: 2018 Optical Fiber Communications Conference and Exposition (OFC). - : Institute of Electrical and Electronics Engineers (IEEE). - 9781943580385 ; , s. 1-3
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Konferensbidrag (refereegranskat)abstract
- A BiCMOS chip-based real-time IM/DD spatial division multiplexing system is experimentally demonstrated for short-reach communications. 100 Gbps/λ/core NRZ and EDB transmission is achieved below 7%-overhead HD-FEC limit after 10km 7-core fiber with optical dispersion compensation.
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| 8. |
- Lin, Rui, et al.
(författare)
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Real-time 100 Gbps/λ/core NRZ and EDB IM/DD transmission over multicore fiber for intra-datacenter communication networks
- 2018
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Ingår i: Optics Express. - : OSA - The Optical Society. - 1094-4087. ; 26:8, s. 10519-10526
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Tidskriftsartikel (refereegranskat)abstract
- A BiCMOS chip-based real-time intensity modulation/direct detection spatial division multiplexing system is experimentally demonstrated for both optical interconnects. 100 Gbps/λ/core electrical duobinary (EDB) transmission over 1 km 7-core multicore fiber (MCF) is carried out, achieving KP4 forward error correction (FEC) limit (BER < 2E-4). Using optical dispersion compensation, 7 × 100 Gbps/λ/core transmission of both non-return-to-zero (NRZ) and EDB signals over 10 km MCF transmission is achieved with BER lower than 7% overhead hard-decision FEC limit (BER < 3.8E-3). The integrated low complexity transceiver IC and analog signal processing approach make such a system highly attractive for the high-speed intra-datacenter interconnects..
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| 9. |
- Lin, Rui, et al.
(författare)
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Spatial division multiplexing for optical data center networks
- 2018
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Ingår i: 22ND INTERNATIONAL CONFERENCE ON OPTICAL NETWORK DESIGN AND MODELING (ONDM 2018). - : IEEE. ; , s. 239-241
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Konferensbidrag (refereegranskat)abstract
- Emerging mobile and cloud applications drive ever-increasing capacity demands, particularly for short-reach optical communications, where low-cost and low-power solutions are highly required. Spatial division multiplexing (SDM) techniques provide a promising way to scale up the lane count per fiber, while reducing the number of fiber connections and patch cords, and hence simplifying cabling complexity. This talk will address challenges on both system and network levels, and report our recent development on SDM techniques for optical data center networks.
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| 10. |
- Liu, Johan, 1960, et al.
(författare)
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Carbon Nanotubes for thermal management of Microsystems
- 2018
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Ingår i: Nanopackaging: Nanotechnologies and Electronics Packaging, Second Edition. - Cham : Springer International Publishing. ; , s. 775-791
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- One important function of electronics packaging is to remove the heat generated by the integrated circuits (ICs). Efficient cooling requires both high heat conduction within the package and efficient heat removal from the package. Elevated temperature is damaging to the chip and its package. Material mismatch causes mechanical stress leading to fatigue, creep, and finally failure; interconnects can melt, and electromigration within the IC is speeded up. Efficient heat removal is not always the case. Plastics is a common packaging material as it is electrically insulating and cheap. The thermal conductivity is, however low, about 0.2 W/mK compared to that of metals (aluminum 220 W/mK and copper 400 W/mK). Other important factors are the heat spreading and thermal interface materials. The components are often mounted on a polymer board which is only cooled by air. The heat transfer coefficient is only 5–15 W/m2 K for natural convection and 15–250 W/m2 K for forced convection in gases [1].
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