2018 Volume 43 Issue 2 Pages 57-60
A polycondensed 2,15-dihydroxy-hexahelicene (HELIXOL) was used to prepare thin films by Langmuir-Blodgett (LB) and spin-coating (SP) techniques, and their structural and photoelectrochemical characteristics were investigated. Atomic force microscopic (AFM) observation indicated that, though the molecule possesses both the hydrophilic –OH groups and hydrophobic aromatic rings, a homogeneous monolayer was not formed by the LB technique, which may be due to lack of sufficient hydrophilicity of the molecule. On the other hand, films with uniform thickness were formed by the SP technique although many holes were generated most likely due to aggregation of the HELIXOL molecules in solvent evaporation process. The energy difference between the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) was estimated by cyclic voltammetry (CV), and the optical band gap energy was determined from the UV-visible spectra. The photocurrent generation was also confirmed through a cyclic light-irradiation experiments with a conventional three-electrode system.
