LAUSR

Abstract In this work, we investigate the lone pair (lp)…π interaction for the halogens (X2=I2, Br2, Cl2, and F2) binding to the rGO surface. Electronic and optical properties of rGO significantly tuned upon adsorption of halogen molecules, although the weak nature of (lp)…π forces. The structure and optical properties of rGO, rGOI2, rGOBr2, rGOCl2 and rGOF2 adducts were investigated by density functional theory (DFT) and time-dependent DFT (TD-DFT) method. Halogen molecules (X2) stable structures were planer on rGO surface and stabilized by the lone pair X2(lp)…π(C) interactions. The surface oxygen atoms contributed to the stability by the O(lp)… π(X2) charge transfer process. Bader analysis reveals significant charge transfer and bond length elongation for X2 on rGO monolayer sheet in the order I2 > Br2 > Cl2 > F2. Surface adsorption of X2 molecules on rGO surface tunes both band gap energy and optical properties. The TDOS and PDOS reveal that X2 adsorption on rGO surface forms an intermediate states in band gap region, which decrease the energy values. These results are beneficial for photocatalysis and light harvesting applications.