A computational study of anisotropic charge transport in air-stable fluorinated benzobisbenzothiophene (FBBBT) derivatives.

A computational study of anisotropical charge transport properties of fluorinated benzobisbenzothiohphene derivatives (FBBBT) is presented. The values of IPadia of all FBBBTs are found in the range of 6.00-6.20 eV inferring the fact that the investigated compounds have ambient air-stability. In addition, the energy levels of FBBBT s are found to be lower than those of benzobisbenzothiophene (BBBT) compound indicating higher charge carrier stability in the former. Hirshfield surface analyses showed that, in all the studied compounds, the principal identifiable interaction were mostly due to F⋯H and H⋯H intermolecular couplings with no contribution from S⋯S bondings. The calculated maximum μhole(μelec) value of the compounds FBBBT-a and FBBBT-b was found to be 0.483 (0.794) cm2V- 1s- 1 and 0.688 (0.542) cm2V- 1s- 1 respectively in the direction of transistor channel (Φ = 93.39 ∘(273.30∘) for FBBBT-a and Φ = 92.24 ∘/272.72 ∘ for FBBBT-b). For FBBBT-c, the maximum μelec(μhole) value of 0.933 (0.233) cm2V- 1s- 1 appeared for Φ = 0 ∘/179.90 ∘. In addition, the compounds FBBBT-a and FBBBT-b possess two additional fluorine atoms attached at the X positions in the backbone, which result in an increment in μelec values (1.4 times and 0.78 times higher than μhole) in these two compounds at a particular crystal direction.