Theoretical investigation of quantum capacitance in the functionalized MoS ₂ -monolayer

Abstract

Abstract In this work, we investigated the electronic structure and the quantum capacitance of a set of functionalized MoS 2 monolayers. The functionalizations have been done by using different ad-atom adsorption on Mo S 2 monolayer. Density functional theory calculations are performed to obtain an accurate electronic structure of ad-atom doped MoS 2 monolayer with a varying degree of doping concentration. Subsequently, the quantum capacitance in each functionalized system was estimated. A marked quantum capacitance above 200 μ F cm −2 has been observed. Our calculations show that the quantum capacitance of MoS 2 monolayer is significantly enhanced with substitutional doping of Mo with transition metal ad-atoms. The microscopic origin of such enhancement in quantum capacitance in this system has been analyzed. Our DFT-based calculation reveals that the generation of new electronic states at the proximity of the band-edge and the shift of Fermi level caused by the ad-atom adsorption results in a very high quantum capacitance in the system.