Blue phosphorene monolayers as potential nano sensors for volatile organic compounds under point defects

Based on spin-polarized DFT calculations, we have studied the interaction mechanism of recently synthesized blue phosphorene (BlueP) monolayers towards selected key volatile organic compounds (VOCs) such as acetone, ethanol and propanal. Our binding energy analysis shows that pristine BlueP weakly binds the VOCs and that this binding does not appreciably change the electronic properties of the monolayer - a prerequisite for any sensing material. However, mono, di, and tri-vacancy defects and Si/S-substitutional doping significantly enhance the binding energies with VOCs. Density of state (DOS) calculations show that upon adsorption of VOCs, mono-vacancy and S-substituted BlueP monolayers undergo a major change in electronic structure, which make them potential candidates for VOCs sensing materials. By contrast, binding of VOCs to di- and tri-vacancy and Si-substitution sites does not alter the electronic structure of BlueP monolayers drastically, therefore, are not qualified for VOCs sensing applications.