Elucidating the Thermal Properties of Partially Chlorinated Graphene Using Molecular Dynamics Simulations.

We investigated thermal transport in partially chlorinated graphene (PCG) via molecular dynamics (MD) simulations using a hybrid force field (h-FF) tailored for chlorinated systems. The h-FF integrates a Tersoff-type potential for C-C interactions with pairwise Morse and Lennard-Jones models for bonded C-Cl and nonbonded C-Cl/Cl-Cl interactions, respectively, including atomic charge equilibration. The Morse potential is fitted to reproduce key chemical and physical properties of C-Cl covalent bonds, while h-FF calibration aims at binding energies and bond lengths predicted by density functional theory. We relaxed suspended and supported PCG sheets with ∼1.5-25% Cl content at 300 K, confirming their thermal stability. To assess the thermal properties of PCG, we analyzed the vibrational modes captured by the simulations and compared the phonon dispersion with that of single-layer graphene (SLG). In PCG, the highest optical modes flattened and acoustic-mode frequencies downshifted due to enhanced phonon scattering, reducing thermal transport. Nonequilibrium MD simulations confirmed a marked reduction in thermal conductivity with increasing Cl content, dropping by ∼70% at ∼1% Cl content and by ∼98% at ∼25% Cl content. The h-FF model enables efficient, accurate predictions of thermally relaxed PCG sheets, offering key insights into their thermal behavior vis-à-vis SLG.