Abstract

This work reports the structure, intermolecular forces, electronic/optical properties, and stability in solution of complexes formed between polycyclic aromatic hydrocarbons (PAH) and phosphorene nanoflakes by density functional theory modeling. PAH molecules reach a strong affinity with phosphorene by forming well-ordered domains, whose interaction strength decreases 13-21% compared to carbonaceous surfaces, e.g., graphene. The adsorption energies are linearly related to the N-H:N-C ratio of PAHs, where N-H and N-C are the numbers of H and C atoms; consequently, the cohesive energy of phosphorene-graphene heterostructures is estimated in 44 meV/atom. Energy decomposition (ALMO-EDA) and electron-density-based analyses support the major role of electrostatics driving forces in the interaction mechanism, which is balanced with dispersion effects for larger PAHs. In addition, phosphorene-PAH complexes display outstanding stability in solution under polar/non-polar solvents, which is due to the high polarity of the complexes and strong overcompensation of destabilizing solvation energies with stabilizing electrostatic effects. Moreover, PAHs behave as n-dopants for phosphorene, inducing small bandgap opening and weak effects on the photophysical fingerprint of phosphorene. Nevertheless, strong electron acceptor/donor and larger PAHs (N-H:N-C 0.5) lead to major effects on the bandgap control, acting as active sites for orbital-controlled interactions. These findings serve as a framework for further investigation of phosphorene-based materials for remediation of PAH pollutants in water treatment technologies and uses of PAHs for phosphorene surface passivation or bandgap engineering for sensing. (C) 2021 Elsevier B.V. All rights reserved.