Spectroscopic, microscopic and electrical characterization of nanoscopic polyindole DNA-templated nanomaterials

Abstract

There has been an increasing demand for in expensive, accurate, movable and reliable nanomaterials for nanoelectronics devices and other applications. Deoxyribonucleic acid has robust nature, therefore it self-fabrication with indole can produce highly organised functional nanostructures that are of great interest for chemical industry applications. This research work is concerned with the synthesis, spectroscopic, microscopic and electrical characterisation of hybrid polyindole (Pln) DNA templated nanowires. Polyindole (PIn) has been templated on λ-DNA via oxidative polymerisation of indole using FeCl3 to produce conductive PIn/DNA nanowires. The formation of PIn/DNA nanowires were verified by FTIR, UV-vis and XPS spectroscopy techniques. AFM, SEM and TEM techniques were used to characterise the nanowires dimensions. AFM studies revealed an average height of 1.60 nm for free DNA and the Pln/DNA nanowires have diameters in the range 2−15 nm with the dominance of 3-4 nm mean diameter range. The electrical properties of Pln/DNA nanowires as drop-cast films were investigated by two-terminal current voltage (I-V) measurements on a probe station. The nanowires were drop-cast (5 μL of as-prepared dispersion) onto platinum microband electrodes. The conductance of these films at 20 °C was of the order of 10-100 μS. In addition, the conductance of PIn/DNA nanowires exhibits Arrhenius behaviour (Ea = 0.80 + 0.06 eV) as a function of temperature. The above results have revealed the potentials of the Pln/DNA nanowire in nanoelectronics applications.