In the realm of energy and materials science, a trio of researchers from the University of Luxembourg—Matteo Vezzelli, Carsten Gachot, and Maria Clelia Righi—have delved into the intriguing world of black phosphorus and its single-layer counterpart, phosphorene. Their study, published in the journal Physical Chemistry Chemical Physics, explores the adhesion energy of phosphorene on various metallic substrates and their oxides, shedding light on its potential applications in the energy sector, particularly in lubrication and tribology.
Black phosphorus and phosphorene have garnered significant attention due to their exceptional tribological properties, which make them promising candidates for advanced lubrication systems. However, recent experiments have shown that their performance can vary greatly depending on the substrate they are used with. To understand this substrate-dependent behavior, the researchers employed density functional theory calculations to investigate the adhesion energy of both pristine and oxidized phosphorene monolayers on different metallic substrates, including aluminum, copper, iron, and chromium, as well as their corresponding oxides.
The study revealed that oxidized phosphorene exhibits greater stability than its pristine form and demonstrates higher adhesion to all the substrates examined. This increased adhesion is attributed to favorable interactions between the oxygen non-bonding states of the oxidized phosphorene and the empty states of the substrates. Notably, the researchers found that adhesion is generally more favorable on pristine metals than on their corresponding oxides, with chromium and iron showing particularly strong interactions due to their partially filled 3d orbitals.
These findings align with experimental observations, where a decrease in the coefficient of friction was noted after scratching the substrate, effectively removing the outermost oxide layer. The study also highlighted the importance of charge redistribution and electronic structure in determining the interfacial bonding characteristics of phosphorene with different substrates. In some configurations, the interaction with the substrate induced a metallic character in phosphorene, further emphasizing the complex nature of these interactions.
The insights gained from this research provide a fundamental understanding of how substrate-dependent adhesion influences the lubricating properties of black phosphorus. This knowledge is crucial for the energy industry, as it can guide the development of more efficient and durable lubrication systems. By optimizing the interaction between phosphorene and various substrates, researchers can enhance the performance of machinery and equipment, leading to reduced energy consumption and improved overall efficiency. The study’s findings were published in the journal Physical Chemistry Chemical Physics, contributing to the growing body of knowledge on two-dimensional materials and their applications in the energy sector.
This article is based on research available at arXiv.