Importance of hydrogen bond configuration on lattice thermal conductivity of hydrogenated borophene.

This article investigates the lattice thermal conductivity (κ_L) of two hydrogenated χ3 borophene structures with distinct boron–hydrogen (B–H) bond configurations using first-principles calculations and the phonon Boltzmann transport equation. It finds that the structure featuring bridged B–H–B bonds, a three-center two-electron (3c–2e) bond, exhibits more than double the thermal conductivity of the structure with only terminal B–H bonds. This enhancement is attributed to the bridged bonds donating electrons to the borophene layer, strengthening boron–boron covalent bonds, causing a blue-shift and bunching of phonon modes, which increases phonon group velocity and reduces phonon–phonon scattering. The study demonstrates that structural engineering of hydrogen bond configurations in two-dimensional borophene can effectively optimize thermal transport properties without altering material composition, offering potential for improved heat dissipation in electronic devices.