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With the increase in heat power density in modern integrating electronics, thermal interface materials (TIM) that can efficiently fill the gaps between the heat source and heat sinks and enhance heat dissipation are urgently needed owing to their high thermal conductivity and excellent mechanical durability. Among all the emerged TIMs, graphene-based TIMs have attracted increasing attention because of the ultrahigh intrinsic thermal conductivity of graphene nanosheets. Despite extensive efforts, developing high-performance graphene-based papers with high through-plane thermal conductivity remains challenging despite their high in-plane thermal conductivity. In this study, a novel strategy for enhancing the through-plane thermal conductivity of graphene papers by in situ depositing AgNWs on graphene sheets (IGAP) was proposed, which could boost the through-plane thermal conductivity of the graphene paper up to 7.48 W m−1 K−1 under packaging conditions. In the TIM performance test under actual and simulated operating conditions, our IGAP exhibits strongly enhanced heat dissipation performance compared to the commercial thermal pads. We envision that our IGAP as a TIM has great potential for boosting the development of next-generation integrating circuit electronics. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: As the power density of electronic devices increases, there has been an urgent demand to develop highly conductive polymer composites to address the accompanying thermal management issues. Due to the ultra‐high intrinsic thermal conductivity, graphene is considered a very promising filler to improve the thermal conductivity of polymers. However, graphene‐based polymer composites prepared by the conventional mixing method generally have limited thermal conductivity, even under high graphene loading, due to the failure to construct efficient heat transfer pathways in the polymer matrix. Here, a spiral graphene framework (SGF) containing continuous and highly ordered graphene microtubes was developed based on a modified CVD method. After embedding into the epoxy (EP) matrix, the graphene microtubes can act as efficient heat pathways, endowing the SGF/EP composites with a high through‐plane thermal conductivity of 1.35 W·m−1·K−1 at an ultralow graphene loading of 0.86 wt%. This result gives a thermal conductivity enhancement per 1 wt% filler loading of 710%, significantly outperforming various graphene structures as fillers. In addition, we demonstrated the practical application of the SGF/EP composite as a thermal interface material for efficient thermal management of the light‐emitting diode (LED). [ABSTRACT FROM AUTHOR]

Urged by the increasing power and packing densities of integrated circuits and electronic devices, efficient dissipation of excess heat from hot spot to heat sink through thermal interface materials (TIMs) is a growing demand to maintain system reliability and performance. In recent years, graphene‐based TIMs received considerable interest due to the ultrahigh intrinsic thermal conductivity of graphene. However, the cooling efficiency of such TIMs is still limited by some technical difficulties, such as production‐induced defects of graphene, poor alignment of graphene in the matrix, and strong phonon scattering at graphene/graphene or graphene/matrix interfaces. In this study, a 120 µm‐thick freestanding film composed of vertically aligned, covalently bonded graphene nanowalls (GNWs) is grown by mesoplasma chemical vapor deposition. After filling GNWs with silicone, the fabricated adhesive TIMs exhibit a high through‐plane thermal conductivity of 20.4 W m−1 K−1 at a low graphene loading of 5.6 wt%. In the TIM performance test, the cooling efficiency of GNW‐based TIMs is ≈1.5 times higher than that of state‐of‐the‐art commercial TIMs. The TIMs achieve the desired balance between high through‐plane thermal conductivity and small bond line thickness, providing superior cooling performance for suppressing the degradation of luminous properties of high‐power light‐emitting diode chips. [ABSTRACT FROM AUTHOR]

Given the thermal management problem aroused by increasing power densities of electronic components in the system, graphene-based papers have raised considerable interest for applications as thermal interface materials (TIMs) to solve interfacial heat transfer issues. Significant research efforts have focused on enhancing the through-plane thermal conductivity of graphene paper; however, for practical thermal management applications, reducing the thermal contact resistance between graphene paper and the mating surface is also a challenge to be addressed. Here, a strategy aimed at reducing the thermal contact resistance between graphene paper and the mating surface to realize enhanced heat dissipation was demonstrated. For this, graphene paper was decorated with polydopamine EGaIn nanocapsules using a facile dip-coating process. In practical TIM application, there was a decrease in the thermal contact resistance between the TIMs and mating surface after decoration (from 46 to 15 K mm2 W−1), which enabled the decorated paper to realize a 26% enhancement of cooling efficiency compared with the case without decoration. This demonstrated that this method is a promising route to enhance the heat dissipation capacity of graphene-based TIMs for practical electronic cooling applications. [ABSTRACT FROM AUTHOR]

With the increasing power density of electrical and electronic devices, there has been an urgent demand for the development of thermal interface materials (TIMs) with high through-plane thermal conductivity for handling the issue of thermal management. Graphene exhibited significant potential for the development of TIMs, due to its ultra-high intrinsic thermal conductivity. In this perspective, we introduce three state-of-the-art graphene-based TIMs, including dispersed graphene/polymers, graphene framework/polymers and inorganic graphene-based monoliths. The advantages and limitations of them were discussed from an application point of view. In addition, possible strategies and future research directions in the development of high-performance graphene-based TIMs are also discussed. [ABSTRACT FROM AUTHOR]

[Display omitted] • Size-dependent assembly of graphene sheets constructs vertical heat pathways across the graphene paper. • GHGP exhibits both high through-plane thermal conductivity and good compressibility. • The cooling efficiency of GHGP was 2.2 times that of the state-of-the-art commercial TIM. Graphene-based papers have recently triggered considerable interests in developing the application as thermal interface materials (TIMs) for addressing the interfacial heat transfer issue, but their low through-plane thermal conductivity (κ ⊥), resulting from the layer-by-layer stacked architecture, limits the direct use as TIMs. Although various hybrid graphene papers prepared by combining the graphene sheets and the thermally conductive insertions have been proposed to solve this problem, achieving a satisfactory κ ⊥ higher than that of commercial TIMs (>5 W m−1 K−1) remains challenging. Here, a strategy aimed at the construction of heat pathways along the through-plane direction inside the graphene paper for achieving a high κ ⊥ was demonstrated through the simultaneous filtration of graphene sheets with two different lateral sizes. The as-prepared graphene paper presented a hierarchical structure composed of loosely stacked horizontal layers formed by large graphene sheets, intercalated by a random arrangement of small graphene sheets. Due to the heat pathways formed by small graphene sheets along the through-plane direction, the hierarchically structured graphene paper exhibited an improved κ ⊥ as high as 12.6 W m−1 K−1 after a common graphitization post-treatment. In the practical test, our proposed paper as an all-graphene TIM achieved an enhancement in cooling efficiency of ≈ 2.2 times compared to that of the state-of-the-art TIM, demonstrating its superior performance to meet the ever-increasing heat dissipation requirement. [ABSTRACT FROM AUTHOR]