Sulfur doping concentration effect on the electronic and structural properties of ZnO nanoparticles: Insights from DFTB calculations

Abstract

The structural and energetic features of sulfur - doped ZnO nanoparticles (NPs) were studied using DFTB approach. The cohesive energy reveals that lower sulfur concentration causes an increase in energetic stability. The sulfur doping concentration rate determines the most electronically stable structure. A reduction in the energy gap with increasing sulfur concentration was predicted from 4.71 eV (undoped ZnO NPs) to 0.68 eV (9S-doped ZnO NP), which represents a similar trend to experimental findings. The LUMO level considerably shifts to higher energies, while the HOMO-level down-shifts with increasing sulfur doping concentration. From ionization potential and electron affinity, the S-ZnO and 9S-ZnO NPs are the least reactive and high kinetic stability. The 9S-ZnO NP has the strongest electrophilic character, and thus, it is the most conductive structure. Finally, current research demonstrated that the sulfur doping concentration can alter the energetic properties of ZnO NP and thus provide its use in desired applications.