Physisorption of DNA Nucleobases on h-BN and Graphene: vdW-Corrected DFT Calculations

Abstract

Using local, semilocal, and van der Waals energy-corrected density-functional theory (PBE + vdW) calculations, we present a comparative study of DNA nucleobases [guanine (G), adenine (A), thymine (T), and cytosine (C)] adsorbed on hexagonal boron nitride (h-BN) sheet and graphene. We find that, despite the very different electronic properties of BN sheet and graphene, the various nucleobase molecules have rather similar binding energies on the two types of sheets. The calculated binding energies of the four nucleobases using the local, semilocal, and PBE + vdW schemes are in the range of 0.54?0.75, 0.06?0.15, and 0.93?1.18 eV, respectively. In particular, the PBE + vdW scheme predicts not only a binding energy predominantly determined by vdW interactions between the base molecules and their substrates decreasing in the order of G > A > T > C but also a very weak hybridization between the molecular levels of the nucleobases and the π-states of the BN sheet or graphene. This physisorption of G, A, T, and C on the BN sheet (graphene) induces a small interfacial dipole, giving rise to an energy shift in the work function by 0.11 (0.22), 0.09 (0.15), ?0.05 (0.01), and 0.06 (0.13) eV, respectively.This work was supported by a National Research Foundation of Korea (NRF) grant funded by the Korean Government (MEST) (no. 2011-0031286), the Sweden?Korea Research Cooperation Programme of the Swedish Foundation for International Cooperation in Research and Higher Education (STINT) through Grant 2011/036, and KISTI supercomputing center through the strategic support program for the supercomputing application research (KSC-2012-C3-18). J.H.L. acknowledges support from the TJ Park Foundation. Figures 1 and 4 were generated using the rasmol and VESTA programs.(46, 47