Effect of strain in beta phosphorus nitride nanosheets on the adsorption of polycyclic aromatic hydrocarbons: a DFT study

Nowadays, many pollutants, especially polycyclic-aromatic-hydrocarbons (PAHs), are a high threat to humans as well as animals due to their carcinogenic behaviour. Therefore, in the present research work, we studied the adsorption behaviour of three different PAHs, namely anthracene, benzo[a]pyrene, and chrysene, on monolayer beta phosphorous nitride nanosheet (β-PN-sheet) using the density-functional-theory (DFT) method. Besides, low-dimensional material possesses many features, including a large active surface region and the electronic properties can be fine-tuned easily, which are the main requirements for chemical sensors. Initially, the structural stability of the β-PN-sheet is confirmed with the support of phonon-band-maps and formation energy. Furthermore, the electronic properties of β-PN-sheet are investigated using band maps and projected-density-of-states (PDOS) maps. We also studied the influence of compressive strain on the electronic properties as well as on the adsorption properties of the β-PN-sheet. The computed band gap of β-PN-sheet slightly increases from 3.355 eV to 3.537 eV owing to the compressive strain. The adsorption behaviour of PAH pollutants on β-PN-sheet is studied with significant factors, namely adsorption energy, relative band gap changes, and Mulliken population analysis. Furthermore, the adsorption of PAHs on β-PN-sheet gets slightly improved with applied compressive strain, and the adsorption energy falls in the scale of physisorption (−0.292 eV to −0.404 eV). Furthermore, a fast recovery time is obtained while desorbing PAH pollutants from the β-PN-sheet. The sensing response of β-PN-sheet to PAHs gets enhanced by applying compressive strain.