Adsorption of Cs-O on Graphene: Modification of the Anderson-Newns Model for the Calculation of Work Function Variation

A modified Anderson-Newns (A-N) model for calculating the work function and the charge transfer of Cs-O-adsorbed graphene surface with the coverage of adsorbed particles is proposed. The calculation of the length of adsorption bond lambda is optimized. The work function and the amount of charge transfer for different coverage of Cs-O molecules are calculated, and the calculated results variations are in reasonable agreement with the experimental data. As coverage theta increases, the amount of charge transfer Z decreases and the work function phi first decreases to a certain value and then increases slightly. When theta = 0.8, the work function phi reaches a minimum value of 0.7.