Tailoring the Adsorption and Electronic Properties of Si-Doped Pyrene for Reversible Ammonia Sensing: A Comparative DFT Study

Abstract

The development of highly sensitive and reversible gas sensors is still an important challenge in nanotechnology. In this work, Density Functional Theory (DFT) calculations are performed to investigate the adsorption of ammonia (NH₃) on pristine and Silicon doped (Si-doped) pyrene surfaces. Our findings show that the pure pyrene surface has a very high adsorption energy of about -4.959 eV, which is related to a strong chemisorption mechanism that leads to surface poisoning and limited reusability. To tune this interaction, we have introduced a silicon atom in the pyrene framework. The electronic environment was greatly influenced by Si-doping, as shown by the charge population analysis and molecular electrostatic potential (MEP). Interestingly, The NH₃ adsorption energy on Si-doped pyrene fell to a moderate value of -4.510 eV. This shift turned the contact into a physisorption-like mechanism that is stable and reversible, making it suited for sensing applications.