Noncovalent Functionalization of Black Phosphorus: Free Energy Simulations vs Adsorption Experiments

Abstract

We investigate the adsorption behavior of various molecules on black phosphorus (BP), employing molecular dynamics (MD)-based free energy calculations in combination with experimental measurements. We find a semiquantitative agreement between experiment and theory. Our approach works best at the low concentration limit, as this allows us to neglect adsorbate-adsorbate interactions, both in solution and on the surface. We also conducted simulations at high concentrations to qualitatively estimate these effects and propose a suitable isotherm model for adsorbates. Our results highlight the impact of molecular structure, shape, polarity, and the alignment of adsorbates relative to the BP surface along with the solvent environment on adsorption. Our approach uses generally available methods and can be extended to arbitrary organic molecules and solvents, potentially allowing for a high throughput screening of candidate molecules for noncovalent functionalization of BP.