Boron nitride nanosheets preserving functionalization strategy for enhancing thermal transport across van der Waals heterostructures

Hexagonal boron nitride nanosheets (BNNS) are promising thermal interface materials (TIMs) for next-generation chip cooling, benefiting from their exceptional thermal conductivity and insulation properties. However, their practical deployment is hindered by the large thermal contact resistance (TCR) at BNNS/substrate interfaces. Previously proposed methods to reduce TCR often compromise the chemical integrity of BNNS, resulting in degraded performance. To overcome this challenge, we introduce a BNNS-preserving approach that involves functionalization strategy on the adjacent substrate—represented here by graphene—to improve interfacial thermal conductance (G) without disrupting the BNNS lattice. G across the BNNS/functionalized-graphene hetero-interface is enhanced by over 800 % compared to the pristine BNNS/graphene interface, reaching up to 1503 MW m⁻² K⁻¹, based on molecular dynamics (MD) simulations. We further employ an MD-based method to quantify interfacial coupling strength, elucidating the mechanism behind the enhancement of G by functionalization. This work offers a promising pathway for integrating BNNS into next-generation chip cooling TIMs.