Two-Dimensional Ternary Pentagonal BCN: A Promising Photocatalyst Semiconductor for Water Splitting with Strong Excitonic Effects

Developing sustainable and stable visible-light-driven photocatalysts to convert solar energy by splitting water into H${}_{2}$ and O${}_{2}$ is a great challenge in applied research. The authors' calculations show that two-dimensional BCN is a very promising semiconductor for optoelectronic applications. Its excellent stability, sizable band gap, high carrier mobility, and distinct excitonic peaks are promising for photovoltaics, with its valence and conduction bands ideally straddling the oxidation and reduction potentials of water. Its optical absorption coefficient in the visible and near-ultraviolet regions is comparable to that of the perovskites currently employed in solar cells.