DFT calculations of 2D graphene like ZnS:Mn sheet for RESOLFT microscopic applications

The reversible saturable optical fluorescence transition (RESOLFT) super-resolution microscopic technique can produce high-resolution images of organic and semiconductor materials by breaking the conventional diffraction limit. In the present paper, we investigate the graphene like zinc sulfide (ZnS) doped with Mn two-dimensional (2D) sheet by using density functional theory computation which is further applied to identify the excitation and depletion laser beam wavelengths for the RESOLFT microscopic applications. The calculated band structure analysis indicates the semiconducting nature of pristine 2D graphene like ZnS with direct energy band gap of 2.60 eV in \(\Gamma\) direction which is consistent with recent reports of the literature. Further, Mn dopant in 2D graphene like ZnS has shown the reduction in the energy band gap in spin up channel and increase in bond lengths adjacent to the dopant in comparison with the undoped ZnS monolayer system. The origin of absorption peak at 2.31 eV is obtained owing to the typical ⁴T₁ and ⁶A₁ spectroscopic transition of Mn dopant in the 2D graphene like ZnS:Mn which is further explored for the RESOLFT measurements by selecting the appropriate excitation and depletion beam wavelengths.