Organic Functionalization and Optimal Coverage of a Silicon(111) Surface in Solvent: A Computational Study

The optimal coverage of a silicon(111) surface functionalized with small organic chains is identified by a computational approach that combines quantum mechanical calculations and classical molecular dynamics simulations. Quantum mechanics is used to evaluate the binding energy of the adsorbed organic molecules. A specific and accurate force-field, developed previously, is employed to perform all-atom molecular dynamic simulations of differently functionalized surfaces in solution. Several coverage percentages with both amine- and methyl-terminated propyl chains are compared through their free energies, pair correlation functions, solvent distributions, and internal conformations. Both types of functionalization yield a coating of similar to 55%, but the alkyl-amine coverage free energy is remarkably lower in all cases due to more favorable interactions with the polar solvent.