| 1. |
- Yang, Fei, et al.
(författare)
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High-Performance Electrothermal Film Based on Laser-Induced Graphene
- 2022
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Ingår i: Advanced Engineering Materials. - : Wiley. - 1527-2648 .- 1438-1656. ; 24:11
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Tidskriftsartikel (refereegranskat)abstract
- Herein, flexible and robust heaters are proposed based on laser-induced graphene (LIG) fabricated photothermally on polyimide (PI) substrates. The heaters are precisely defined by a computer numerical control (CNC) platform-driven laser diode with a one-step process. The electrothermal performance of the heaters can be adjusted by tuning the laser driving speed in a certain range under a given input power. The fabricated heater shows a high saturation temperature (270 °C), the fast response time (10 s), and satisfactory convective heat-transfer coefficient (42 W m−2°C−1). Simultaneously, the developed heaters demonstrate excellent flexibility, robust adhesion, and good long-time stability. The experimental results pave the way for high-performance, environmentally friendly, robust, and flexible heaters.
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| 2. |
- Bao, Jie, 1982, et al.
(författare)
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Two-dimensional hexagonal boron nitride as lateral heat spreader in electrically insulating packaging
- 2016
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Ingår i: Journal of Physics D: Applied Physics. - : IOP Publishing. - 1361-6463 .- 0022-3727. ; 49:July 2016, s. 265501-
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Tidskriftsartikel (refereegranskat)abstract
- The need for electrically insulating materials with a high in-plane thermal conductivity for lateral heat spreading applications in electronic devices has intensified studies of layered hexagonal boron nitride (h-BN) films. Due to its physicochemical properties, h-BN can be utilised in power dissipating devices such as an electrically insulating heat spreader material for laterally redistributing the heat from hotspots caused by locally excessive heat flux densities. In this study, two types of boron nitride based heat spreader test structures have been assembled and evaluated for heat dissipation. The test structures separately utilised a few-layer h-BN film with and without graphene enhancement drop coated onto the hotspot test structure. The influence of the h-BN heat spreader films on the temperature distribution across the surface of the hotspot test structure was studied at a range of heat flux densities through the hotspot. It was found that the graphene-enhanced h-BN film reduced the hotspot temperature by about 8–10°C at a 1000 W/cm2 heat flux density, a temperature decrease significantly larger than for h-BN film without graphene enhancement. Finite element simulations of the h-BN film predict that further improvements in heat spreading ability are possible if the thermal contact resistance between the film and test chip are minimised.
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| 3. |
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| 4. |
- Huang, Shirong, et al.
(författare)
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Graphene Based Heat Spreader for High Power Chip Cooling Using Flip-chip Technology
- 2013
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Ingår i: 2013 IEEE 15th Electronics Packaging Technology Conference (EPTC 2013). - 9781479928330 ; , s. 347-352
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Konferensbidrag (refereegranskat)abstract
- Monolayer graphene was synthesized through thermal chemical vapor deposition (TCVD) as heat spreader for chip cooling. Platinum (Pt) serpentine functioned as hot spot on the thermal testing chip. The thermal testing chip with monolayer graphene film attached was bonded using flip-chip technology. The temperature at the hot spot with a monolayer graphene film as heat spreader was decreased by about 12°C and had a more uniform temperature compared to those without graphene heat spreader when driven by a heat flux of about 640W/cm 2 . Further improvements to the cooling performance of graphene heat spreader could be made by optimizing the synthesis parameters and transfer process of graphene films. © 2013 IEEE.
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| 5. |
- Lu, Pei, et al.
(författare)
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Thermal Conduction of Fiber-Reinforced Polymer under Loading
- 2021
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Ingår i: 2021 23rd European Microelectronics and Packaging Conference and Exhibition, EMPC 2021.
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Konferensbidrag (refereegranskat)abstract
- Thermal performance of an epoxy resin reinforced by carbon fibers is studied by numerical simulation method. Various carbon fiber structures are taken into consideration and the effective thermal conductivity of the composite carbon fiber waved structure is obtained. The influences of the number, size, shape, spacing and arrangement of the carbon fibers on the thermal conduction of the composites are analyzed. The deformation of the composite under mechanical loading and the corresponding the thermal conductivity of the carbon fiber-reinforced epoxy resin are also investigated.
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| 6. |
- Zhang, Wei, et al.
(författare)
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The Central Role of Ligand Conjugation for Properties of Coordination Complexes as Hole-Transport Materials in Perovskite Solar Cells
- 2019
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Ingår i: ACS Applied Energy Materials. - : AMER CHEMICAL SOC. - 2574-0962. ; 2:9, s. 6768-6779
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Tidskriftsartikel (refereegranskat)abstract
- Two zinc-based coordination complexes Y3 and Y4 have been synthesized and characterized, and their performance as hole-transport materials (HTMs) for perovskite solar cells (PSCs) has been investigated. The complex Y3 contains two separate ligands, and the molecular structure can be seen as a disconnected porphyrin ring. On the other hand, Y4 consists of a porphyrin core and therefore is a more extended conjugated system as compared to Y3. The optical and redox properties of the two different molecular complexes are comparable. However, the hole mobility and conductivity of Y4 as macroscopic material are remarkably higher than that of Y3. Furthermore, when employed as hole-transport materials in perovskite solar cells, cells containing Y4 show a power conversion efficiency (PCE) of 16.05%, comparable to the Spiro-OMeTAD-based solar cells with an efficiency around 17.08%. In contrast, solar cells based on Y3 show a negligible efficiency of about 0.01%. The difference in performance of Y3 and Y4 is analyzed and can be attributed to the difference in packing of the nonplanar and planar building blocks in the corresponding materials.
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| 7. |
- Zhang, Yong, 1982, et al.
(författare)
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2D HEAT DISSIPATION MATERIALS FOR MICROELECTRONICS COOLING APPLICATIONS
- 2016
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Ingår i: China Semiconductor Technology International Conference 2016, CSTIC 2016. - 9781467388047
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Konferensbidrag (refereegranskat)abstract
- The need for faster and smaller, as well as more reliable and efficient consumer electronic products has resulted in microelectronic components that produce progressively more heat. The resultant reliability issues from the increased heat flux are serious and hinder technological development. One solution for microelectronics cooling applications is 2D materials applied as heat spreaders and these include monolayer graphene, graphene based films, and monolayer hexagonal boron nitride and BN based films. In addition, thermal performances of the graphene heat spreader were also studied under different packaging structures, including wire bonding, cooling fins and flip chips. Finally, 2D hexagonal Boron nitride (h-BN) heat spreaders, fabricated by different methods, had their heat dissipation performances characterized by different thermal characterization methods, such as resistance temperature detector (RTD) and Infrared (IR) methods. In conclusion, these new novel 2D materials developed show great potential for microelectronics cooling applications.
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| 8. |
- Zhang, Yong, 1982, et al.
(författare)
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Improved Heat Spreading Performance of Functionalized Graphene in Microelectronic Device Application
- 2015
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Ingår i: Advanced Functional Materials. - : Wiley. - 1616-3028 .- 1616-301X. ; 25:28, s. 4430-4435
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Tidskriftsartikel (refereegranskat)abstract
- It is demonstrated that a graphene-based film (GBF) functionalized with silane molecules strongly enhances thermal performance. The resistance temperature detector results show that the inclusion of silane molecules doubles the heat spreading ability. Furthermore, molecular dynamics simulations show that the thermal conductivity () of the GBF increased by 15%-56% with respect to the number density of molecules compared to that with the nonfunctionalized graphene substrate. This increase in is attributed to the enhanced in-plane heat conduction of the GBF, resulting from the simultaneous increase of the thermal resistance between the GBF and the functionalized substrate limiting cross-plane phonon scattering. Enhancement of the thermal performance by inserting silane-functionalized molecules is important for the development of next-generation electronic devices and proposed application of GBFs for thermal management.
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| 9. |
- Zhang, Yong, 1982, et al.
(författare)
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Improved Thermal Properties of Three-Dimensional Graphene Network Filled Polymer Composites
- 2022
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Ingår i: Journal of Electronic Materials. - : Springer Science and Business Media LLC. - 1543-186X .- 0361-5235. ; 51:1, s. 420-425
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents the improved thermal property of three-dimensional (3D) graphene network modified polydimethylsiloxane (PDMS) composites. It shows that with a 2 wt.% loading of graphene foams (GF), the thermal conductivity of GF/PDMS composite was successfully increased from 0.19 W/mK to 0.42 W/mK, which is 2.2 times higher than that of neat PDMS. However, if GF was transformed into graphene sheets (GS) by sonication, the thermal conductivity of GS/PDMS was decreased to 0.28 W/mK. The remarkable improvement of the thermal properties is attributed to the 3D interconnected graphene network in GF, which form continuous heat transfer networks. Furthermore, the finite element analysis was conducted to evaluate the effect of GFs in composites, where some parameters such as thickness and thermal conductivity were analyzed and discussed. Our results indicate that the continuous 3D GFs holds great potential as fillers to improve the thermal property of polymer materials.
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| 10. |
- Zhang, Yong, 1982, et al.
(författare)
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Properties of Undoped Few-Layer Graphene-Based Transparent Heaters
- 2020
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Ingår i: Materials. - : MDPI AG. - 1996-1944. ; 13:1
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Tidskriftsartikel (refereegranskat)abstract
- In many applications like sensors, displays, and defoggers, there is a need for transparent and efficient heater elements produced at low cost. For this reason, we evaluated the performance of graphene-based heaters with from one to five layers of graphene on flexible and transparent polyethylene terephthalate (PET) substrates in terms of their electrothermal properties like heating/cooling rates and steady-state temperatures as a function of the input power density. We found that the heating/cooling rates followed an exponential time dependence with a time constant of just below 6 s for monolayer heaters. From the relationship between the steady-state temperatures and the input power density, a convective heat-transfer coefficient of 60 W·m−2·°C−1 was found, indicating a performance much better than that of many other types of heaters like metal thin-film-based heaters and carbon nanotube-based heaters.
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