Charge Transport in Guanine-Based Materials

Temperature-induced dynamic disorder is one of the great unknowns in charge transport through DNA and DNA-related systems. Using guanine crystals as a model system, we studied the temperature dependence and anisotropy of charge-carrier (hole) transport in guanine-based materials. Employing the Kubo formalism, we calculated the hole mobilities with ab initio DFT material parameters. Our findings are discussed in relation to transport pathways in DNA-based structures such as guanine quadruplexes and ribbons, which are considered to play a major role in DNA-based nanoelectronics. The mobility results are interpreted by means of a novel visualization method for transport channels that we derived from overlapping wave functions. An analysis of coherent and incoherent contributions to the mobility shows that, even in materials with high purity and long-range order such as crystals, only incoherent phonon-assisted hopping occurs at room temperature.