Oxidation mechanism of black phosphorene and its passivation: A DFT and MD study

Black phosphorene, known for its remarkable physical properties, holds great promise for nanoelectronic and optoelectronic applications. However, its high reactivity with oxygen poses a significant challenge to its stability. In this study, we employ density functional theory (DFT) calculations and molecular dynamics simulations to investigate the effects of oxidation on the structural, electronic, and optical properties of phosphorene, as well as the impact of 1,4,5,8-naphthalene tetracarboxylic dianhydride (NTCDA) as a passivation layer. DFT results reveal that oxygen adsorption progressively reduces the electronic bandgap, ultimately leading to a transition to metallic behavior as oxygen molecules are adsorbed. Charge density and Bader charge analyses confirm significant charge transfer from phosphorus to oxygen, which alters the electronic properties of phosphorene. Oxidation also severely degrades the optical properties, reducing optical absorption. Importantly, the adsorption of the NTCDA monolayer significantly stabilizes phosphorene against oxidation and preserves its semiconducting character. These results demonstrate that NTCDA acts as an effective protective passivation layer, partially maintaining both the electronic and optical properties of phosphorene under oxidative conditions.