Rational design of high-performance thermal interface materials based on gold-nanocap-modified vertically aligned graphene architecture

The rapid increase of the packaging integration and power density of devices in electronics leads to urgent demands for high-performance thermal interface materials (TIMs) to efficiently solve the accompanying thermal management problem. Although various highly thermally conductive materials (such as graphene, carbon nanotube, and boron nitride nanosheet) combined with diversified structure design have been proposed to address this issue, it remains challenging to achieve a satisfactory TIM with both high through-plane thermal conductivity (κ⊥) and low contact thermal resistance (Rcontact) for meeting the practical application requirements. This study solves this problem by constructing a loosely packed and vertically aligned graphene monolith (VAGM), which was prepared by simply rolling up hybrid double-layer strips composed of porous polymer foam adhered onto the graphene paper, exhibiting an ultrahigh κ⊥ of 276 W m-1 K-1. Moreover, a cap modification strategy by transferring the nanometer-thick gold (Au) foils onto both sides of VAGM was carried out to further optimize the contact state with roughness surface from heater/heat sink, finally giving a low Rcontact of 0.41 K cm2 W-1 (double sides). As a result, our proposed graphene-based TIM exhibits an enhancement in cooling efficiency of ≈1.15 times compared to that of the state-of-the-art TIM (≈30 W m-1 K-1) in the TIM performance test, manifesting its superior ability to meet the ever-increasing heat dissipation requirement.