Near-Theoretical Thermal Conductivity Silver Nanoflakes as Reinforcements in Gap-Filling Adhesives

Lu Chen; Te-Huan Liu; Xiangze Wang; Yandong Wang; Xiwei Cui; Qingwei Yan; Le Lv; Junfeng Ying; Jingyao Gao; Meng Han; Jinhong Yu; Chengyi Song; Jinwei Gao; Rong Sun; Chen Xue; Nan Jiang; Tao Deng; Kazuhito Nishimura; Ronggui Yang; Cheng-Te Lin; Wen Dai

doi:10.1002/adma.202211100

Near-Theoretical Thermal Conductivity Silver Nanoflakes as Reinforcements in Gap-Filling Adhesives

Adv Mater. 2023 Aug;35(31):e2211100. doi: 10.1002/adma.202211100. Epub 2023 Jun 20.

Authors

Lu Chen^{1

2}, Te-Huan Liu³, Xiangze Wang³, Yandong Wang^{1

2}, Xiwei Cui^{1

2}, Qingwei Yan^{1

2}, Le Lv^{1

2}, Junfeng Ying^{1

2}, Jingyao Gao⁴, Meng Han⁵, Jinhong Yu^{1

2}, Chengyi Song⁶, Jinwei Gao^{7

8}, Rong Sun⁵, Chen Xue^{1

2}, Nan Jiang^{1

2}, Tao Deng⁶, Kazuhito Nishimura⁹, Ronggui Yang³, Cheng-Te Lin^{1

2}, Wen Dai^{1

2}

Affiliations

¹ Key Laboratory of Marine Materials and Related Technologies, Zhejiang Key Laboratory of Marine Materials and Protective Technologies, Ningbo Institute of Materials Technology and Engineering (NIMTE), Chinese Academy of Sciences, Ningbo, 315201, P. R. China.
² Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, P. R. China.
³ School of Energy and Power Engineering, Huazhong University of Science and Technology Wuhan, Wuhan, 430074, P. R. China.
⁴ Jiangxi Copper Technology Research Institute Co., Ltd., Nanchang, Jiangxi, 330096, P. R. China.
⁵ Shenzhen Institute of Advanced Electronic Materials, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, P. R. China.
⁶ The State Key Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, 800 Dong Chuan Road, Shanghai, 200240, P. R. China.
⁷ Guangdong Provincial Key Laboratory of Optical Information Materials and Technology, Academy of Advanced Optoelectronics, South China Normal University, Guangzhou, 510006, P. R. China.
⁸ Guangdong Provincial Engineering Technology Research Center for Transparent Conductive Materials, Guangzhou, 510006, P. R. China.
⁹ Advanced Nano-processing Engineering Lab, Mechanical Systems Engineering, Kogakuin University, Tokyo, 192-0015, Japan.

PMID: 36929098
DOI: 10.1002/adma.202211100

Abstract

The rapid development of highly integrated microelectronic devices causes urgent demands for advanced thermally conductive adhesives (TCAs) to solve the interfacial heat-transfer issue. Due to their natural 2D structure and isotropic thermal conductivity, metal nanoflakes are promising fillers blended with polymer to develop high-performance TCAs. However, achieving corresponding TCAs with thermal conductivity over 10 W m^-1 K^-1 at filler content below 30 vol% remains challenging so far. This longstanding bottleneck is mainly attributed to the fact that most current metal nanoflakes are prepared by "bottom-up" processes (e.g., solution-based chemical synthesis) and inevitably contain lattice defects or impurities, resulting in lower intrinsic thermal conductivities, only 20-65% of the theoretical value. Here, a "top-down" strategy by splitting highly purified Ag foil with nanoscale thickness is adopted to prepare 2D Ag nanoflakes with an intrinsic thermal conductivity of 398.2 W m^-1 K^-1 , reaching 93% of the theoretical value. After directly blending with epoxy, the resultant Ag/epoxy exhibits a thermal conductivity of 15.1 W m^-1 K^-1 at low filler content of 18.6 vol%. Additionally, in practical microelectronic cooling performance evaluations, the interfacial heat-transfer efficiency of the Ag/epoxy achieves ≈1.4 times that of the state-of-the-art commercial TCA.

Keywords: 2D materials; Ag nanoflakes; interfacial heat transfer; thermal interface materials; thermal percolation.

Abstract

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