Red or Black Phosphorus Yield the Same Blue

After the discovery of graphene, many other 2D materials have been theoretically predicted and successfully synthesized. Among these, single-sheet black phosphorus—known as phosphorene—has emerged as a promising contender in the field of 2D semiconductors. Phosphorene offers a wide tunability of the band gap, ranging from 0.3 to 2 eV depending on the film thickness, along with other intriguing properties such as high carrier mobility and an anisotropic structure that modulates its physical and chemical characteristics. These features pave the way for novel and exciting applications, particularly in field-effect transistors and optoelectronic devices.In previous studies, a single layer of blue phosphorene interspersed with Au atoms was synthesized using purified black phosphorus as a precursor. Building on the observation that phosphorus vapor primarily consists of P clusters, our research aimed to produce blue phosphorus using the more cost-effective purified red phosphorus as an evaporant. Utilizing a combination of complementary experimental techniques and theoretical calculations, we demonstrate that depositing black or red phosphorus on Au(111) substrates results in the formation of the same blue phosphorus film. Furthermore, our comprehensive approach, which integrates experimental data with theoretical predictions, confirms the complex atomic model of this novel 2D material. While this is not a novel point, we emphasize that exploiting tools capable of diagnosing the possible presence of host heteroatoms in the 2D mesh is crucial for this quest. Overall, the development of reliable and sensitive comparison protocols between experimental results and theoretical forecasts can serve as the foundation for engineering next-generation materials.