Physisorption of DNA nucleobases on h-BN and graphene: vdW-corrected DFT calculations

TL;DR

This study compares how DNA nucleobases adsorb on h-BN and graphene sheets using advanced DFT calculations, revealing similar binding energies and weak hybridization, with implications for surface interactions and energy shifts.

Contribution

It provides a detailed comparison of nucleobase adsorption on h-BN and graphene using vdW-corrected DFT, highlighting similar binding energies and weak hybridization effects.

Findings

Binding energies range from 0.54 to 1.18 eV depending on the scheme.

Adsorption induces small interfacial dipoles and work function shifts.

Weak hybridization between nucleobases and substrate π-states.

Abstract

We present a comparative study of DNA nucleobases [guanine (G), adenine (A), thymine (T), and cytosine (C)] adsorbed on hexagonal boron nitride (\textit{h}-BN) sheet and graphene, using local, semilocal, and van der Waals (vdW) energy-corrected density-functional theory (DFT) calculations. Intriguingly, despite the very different electronic properties of BN sheet and graphene, we find rather similar binding energies for the various nucleobase molecules when adsorbed on the two types of sheets. The calculated binding energies of the four nucleobases using the local, semilocal, and DFT+vdW schemes are in the range of 0.54 ${\sim}$ 0.75 eV, 0.06 ${\sim}$ 0.15 eV, and 0.93 ${\sim}$ 1.18 eV, respectively. In particular, the DFT+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 ${\pi}$-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.