A DFT study on the functionalization of a BN nanosheet with PC-X, (PC = phenyl carbamate, X = OCH3, CH3, NH2, NO2 and CN)

By using density functional theory calculations, we investigated the chemical functionalization of a BN nanosheet with different organo-azo derivatives including PC-X, (PC = phenyl carbamate, X = OCH3, CH3, NH2, NO2 and CN) in terms of geometric, energetic, and electronic properties. Reaction energies have been calculated to be in the range of 0.19 to 0.35 eV which is augmented by increasing the electron withdrawing characteristic of the functional groups so that the relative magnitude order is -NO2 > -CN > -OCH3 > -CH3 > -NH2. The chemical functionalization leads to a decrease in HOMO/LUMO energy gap of BN sheet especially after adsorption of PC-NO2 by about 1.88 eV. Conduction level and Fermi level of the BN sheet are shifted to lower energies upon the functionalization of the sheet with PC-NO2 and PC-CN, thus, it leads to an increment in work function of the sheet, impeding the field electron emission. (C) 2012 Elsevier B.V. All rights reserved.