High through-plane thermal conductivity of graphite films with opened micro-window arrays

Graphene's ultrahigh in-plane thermal conductivity makes it an ideal material for thermally conductive films in various electronic applications. However, the inherently weak interlayer interaction in conventional graphite films (GrF) results in low through-plane thermal conductivity. Here, we firstly developed a novel structure of opened micro-window arrays in the graphite film (MW-GrF) to significantly enhance the through-plane thermal conductivity by the laser-etching-assisted and micro-origami methods. The opened micro-window arrays are acted as bridges to promote interfacial thermal transport via utilizing the ultrahigh in-plane thermal conductivity of micro-windows, which can achieve a reduction of ∼ 60 % in through-plane thermal resistance, with the lowest value of 0.286 K cm² W^-1. Meanwhile, the through-plane thermal conductivity of MW-GrF was greatly improved to 82.4-89.6 W m^-1 K^-1 compared to the original GrF with 4.4-6.9 W m^-1 K^-1. This work provides a simple, scalable and programmable method for finely tailoring the through-plane thermal properties of graphene films, making them promising candidates for highly efficient heat dissipation in future high-power chips.