Optimal water adsorption on phosphorene

Water adsorption on phosphorene has fundamental importance to device development from black phosphorus, but the stable adsorption configuration remains in confusion. Here we explore the water adsorption configurations on phosphorene through comprehensive first principle calculations. It is found that water takes an optimal adsorption configuration on phosphorene with one of the hydrogen atoms pointing to the surface of phosphorene. This optimal adsorption configuration is significantly more stable than all the configurations reported previously for the strongest van de Walls interaction between the adsorbed water and the phosphorene compared to other adsorption configurations. It is also shown that water serves as an acceptor in the optimal adsorption configuration, clarifying the confusing results from less stable configurations.