Electronic and Optical Properties of Self-Assembled Peptide Nucleic Acids.

In this work, we analyze theoretically electronic and optical properties of self-assembled GC and GG di-peptide nucleic acids (PNAs) that were characterized experimentally (Berger, et al., Nat. Nanotechnol. 2015, 10, 353). To assess their potential as electronic and optical materials by using density functional theory (DFT), we first predict that the lattice constants, Watson-Crick hydrogen bond and stacking distances of GC PNA are close to the experimental structure, while for GG, where the structure has not been determined experimentally, we propose a well-converged crystal structure. The band gap for GC is found to be consistent with the measured emission, while a larger bandgap is predicted for GG. Calculated optical absorption spectra for GC and GG PNAs using time-dependent DFT will be discussed. In addition, based on electron transport calculations for the GC PNA along the stacking direction by using a non-equilibrium Green’s function method with DFT, derivation of a phenomenological scattering potential and transport channels near the Fermi level will be described.