Doping of fluorographene by surface adsorbates

Density functional theory is used to investigate the possibility of doping fluorographene by surface adsorbates. The structure and electronic properties of fluorographene with adsorbed K, Li, Au atoms, and F4-TCNQ molecule are described. It is shown that adsorption of K or Li atoms results in electron doping of fluorographene, while Au atoms and F4-TCNQ introduce deep levels inside the band gap. The calculated value of the fluorographene work function is extremely high, 7.3 eV, suggesting that p-type doping is difficult to achieve.