Thermal management with a highly emissive and thermally conductive graphite absorber
Tingbiao Guo,
Yaoran Sun,
Julian Evans,
Nan Wang,
Yang Fu,
Sailing He
Affiliations
Tingbiao Guo
Centre for Optical and Electromagnetic Research, College of Optical Science and Engineering, Zhejiang University, Hangzhou 310058, People’s Republic of China
Yaoran Sun
Centre for Optical and Electromagnetic Research, College of Optical Science and Engineering, Zhejiang University, Hangzhou 310058, People’s Republic of China
Julian Evans
Centre for Optical and Electromagnetic Research, College of Optical Science and Engineering, Zhejiang University, Hangzhou 310058, People’s Republic of China
Nan Wang
Centre for Optical and Electromagnetic Research, College of Optical Science and Engineering, Zhejiang University, Hangzhou 310058, People’s Republic of China
Yang Fu
Centre for Optical and Electromagnetic Research, College of Optical Science and Engineering, Zhejiang University, Hangzhou 310058, People’s Republic of China
Sailing He
Centre for Optical and Electromagnetic Research, College of Optical Science and Engineering, Zhejiang University, Hangzhou 310058, People’s Republic of China
Thermal management on a variety of length scales is essential for many industrial, solar and computational systems. Here we explore the thermal properties of a nearly perfect graphite absorber with both high emissivity and thermal conductivity which is fabricated by simple one-step etching. The hemispherical reflectance of the absorber is around 1% in the visible range and the normal specular reflectance is less than 1% from 1.5 μm to 10 μm. The thermal conductivity of the absorber is measured above 630 Wm-1K-1, which is 2.5 times larger than the aluminum used in commercial heat sinks. Heat dissipation testing indicates that a device is 3.7 ± 2 degrees cooler with the graphite absorber as the heat spreader than a pristine graphite sheet and 9.1 ± 2 degrees cooler than an Au-coated graphite sheet, primarily due to improved radiation cooling. A theoretical analysis accounts for the results. Further analysis suggests that the radiative heat dissipation is more prominent in the low-convection environment, especially for a convection coefficient below 10 Wm-2K-1.
