Elucidating the Oxidation Process and Enhanced Stability of Black Phosphorus through NTCDA Passivation: A Molecular Dynamics Study

Understanding the oxidation mechanisms of black phosphorus (BP) at the atomic scale is essential for developing effective passivation strategies to enhance its stability in ambient conditions. To explore this, the effects of O₂ and H₂O molecules on BP layers are elucidated using reactive force field (ReaxFF) molecular dynamics simulations at constant concentrations of molecules and room temperature. As a potential solution, the passivation efficacy of 1,4,5,8-naphthalenetetracarboxylic dianhydride (NTCDA) is evaluated. The initial oxidation processes are analyzed through atomic structural changes, charge dynamics, and radial distribution functions. Moreover, the thickness of the oxidized BP layers is quantitatively determined. Results show that elevated O₂ concentrations significantly accelerate oxidation and increase the thickness of the oxidized layers, while H₂O has a weaker influence. The interaction between O⁻ and H⁺ ions in H₂O reduces its interaction with BP, but O₂ molecules cause H₂O to become negatively charged, allowing it to interact with P⁺ ions. Importantly, passivating BP with NTCDA effectively mitigates oxidation, creating a protective layer that repels O₂ molecules. Ultimately, this study reveals the initial oxidation and passivation processes of BP layers, offering crucial theoretical insights to guide experimental methods and practical applications in semiconductor devices.