Strain engineering of selective chemical adsorption on monolayer black phosphorous

Controllable sensitivity of the surface chemical adsorption to toxic gases is important for the next generation gas sensors. Two dimensional (2D) layered nanomaterials are the excellent candidates to sensitively detect the chemical species by tuning the properties of the materials. Recently, the single and multi-layer black phosphorous (phosphorene) were discovered to exhibit better performances than graphene in the applications of field effect transistors, PN junctions, and photodetectors, and they are also ultrasensitive to the chemical gases. In this study, by using first principle calculations, we report that the adsorption of NO₂ on strained monolayer phosphorene can be noticeably enhanced, while the electronic properties of monolayer phosphorene can be apparently adjusted. The monolayer phosphorene exhibits the superior selective adsorption for NO₂ over NO, NH₃, CO and CO₂. The compressive strains were demonstrated to be able to effectively adjust the adsorptions of NO₂. Our findings provide critical information for the novel design of phosphorene-based highly sensitive nanoscale sensors and electromechanical devices.