The Influence of Ionic Liquids Adsorption on the Electronic and Optical Properties of Phosphorene and Arsenene with Different Phases: A Computational Study

Density functional theory (DFT) calculations have been performed to investigate the interfacial interactions of ionic liquids (ILs) on the alpha- and beta-phases of phosphorene (P) and arsenene (As). Nine representative ILs based on the combinations of 1-ethyl-3-methylimidazolium ([EMIM](+)) N-methylpyridinium ([MPI](+)), and trimethylamine ([TMA](+)) cations paired to tetrafluoroborate ([BF4](-)), trifluoromethanesulfonate ([TFO](-)), and chloridion (Cl-) anions were used as adsorbates on the 2D P and As nanosheets with different phases to explore the effect of IL adsorption on the electronic and optical properties of 2D materials. The calculated structure, adsorption energy, and charge transfer suggest that the interaction between ILs and P and As nanosheets is dominated by noncovalent forces, and the most stable adsorption structures are characterized by the simultaneous interaction of the cation and anion with the surface, irrespective of the types of ILs and surfaces. Furthermore, the IL adsorption leads to the larger change in the electronic properties of beta-phase P and As than those of their alpha-phase counterparts, which demonstrates that the adsorption properties are not only related to the chemical elements, but also closely related to the phase structures. The present results provide insight into the further applications of ILs and phosphorene (arsenene) hybrid materials.

Automated summary

Density functional theory (DFT) calculations were used to investigate the interfacial interactions of ionic liquids (ILs) on different phases of phosphorene (P) and arsenene (As). The results show that the interaction between ILs and P, As nanosheets is dominated by noncovalent forces, and the most stable adsorption structures are characterized by the simultaneous interaction of the cation and anion with the surface. IL adsorption has a larger impact on the electronic properties of beta-phase P and As compared to their alpha-phase counterparts, indicating that the adsorption properties are closely related to the phase structures.