Mn-Doped black phosphorene for ultrasensitive hydrogen sulfide detection: periodic DFT calculations

This paper addresses the comparative detection capabilities of pristine (BP) and Mn-doped (MP1) black phosphorene sensors toward the noxious H₂S molecule within a periodic density functional framework. The most stable configuration of the H₂S molecule on MP1 preferred the placement of an S-H bond on top of the Mn dopant, while the H-S-H plane was slightly tilted with respect to the surface. The formation of the Mn-modified phosphorene sensor was found to be highly favorable (-3.79 eV), which also enhanced the stabilization of the H₂S molecule (-0.85 eV at HSE06/TZVP). The electronic band structures revealed a direct-to-indirect transition and the observation of an n-type semiconductor through Mn doping. The results indicated that the pristine phosphorene could be converted into an ultrasensitive reusable H₂S nanosensor in terms of both electric conductance (3747) and work function (11 times more sensitive) through Mn doping. The new sensor was also highly selective, with a sensitivity ratio of at least 52.6 with respect to the air components. The recovery time of the Mn-doped material (2.7 s at ambient temperature) was more promising than that of BP from a practical point of view. More discussion of the material is presented with the electronic properties, frontier molecular orbitals, and density of states at rest and under operating conditions.