Band gaps and optical spectra from single‐ and double‐layer fluorographene to graphite fluoride: many‐body effects and excitonic states

Abstract

First‐principle band gaps and optical absorption spectra of single‐ and double‐layer fluorographene with bulk graphite fluoride are compared. The electronic properties are calculated using the many‐body GW approximation and the optical spectra using the Bethe‐Salpeter equation (BSE). The inclusion of electron‐hole interactions is crucial for predicting low energy excitonic absorption peaks. The position of the first exciton peak is identical in single‐, double‐ and multilayer fluorographene, which may indicate that the onset of the absorption spectra does not differ in these materials.