Blue-Green-Black phosphorene allotropes conversion: Energetically easy and potentially promising

Abstract

Three allotropic forms of phosphorene (Blue, Green and Black) are studied from both structural and electronic points of view. P–P bonds orientation change from vertical to lateral directions is behind the change from Blue to Black forms via Green one. The energetic profile shows that this conversion could take place easily. The rippling mode of the phosphorene sheet is rationalized using the naturel bond orbital (NBO) analysis. We present the landforms of these sheets as a result of MOs interaction depending on the kind (σ, σ∗ and/or LP), on the mode (lateral or axial), and on the position (geminal, vicinal or remote) of these MOs leading to an electronic delocalization phenomenon called hyperconjugation. The conversion Blue-Green-Black phosphorenes is accompanied by a change of properties; for example, from natural band gap (Blue form) to a sizable and tunable one (Green and Black forms). This change would confer to the phosphorene the ability to be involved in the electronics and optoelectronics manufacturing. The geometrical optimization and the hyperconjugative rationalization were undertaken at B3LYP/6-311+G(d,p) level of theory and NBO partitioning scheme respectively.