Semiconducting asphaltene thin films: preparation and characterization

Abstract

Asphaltene thin films of 100‐500 nm thicknesses were deposited on soda lime glass substrates from toluene solution by spray pyrolysis method. Atomic force microscopy (AFM), photoluminescence (PL), spectroscopic ellipsometry (SE), and electron paramagnetic resonance (EPR) methods were used for characterization of the films. The obtained films were found to be broad band semiconducting material with band gap energy ∼ 3.1 eV and exhibited n‐type conductivity with resistivity ρ ∼ 8·102Ω·cm. Concentration of free radicals and g‐factor were about of ∼ 1018 spin/g and 2.00307, respec­tively. (© 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)