Tunable optical response of defective rGO-like carbon films studied by spectroscopic ellipsometry

We report the tunable optical response of biomass-derived defective rGO-like carbon films by spectroscopic ellipsometry in the energy range of 1.5–5.5 eV deposited by the spray pyrolysis method. The defects in rGO-like carbon were generated by a heating process from 400 to 1000 °C with an increase of every 200 °C. The investigation results showed that the optical response at the imaginary part peak of the dielectric constant and optical conductivity of the defective rGO-like films increased and red-shifted from 5.4 to 5.1 eV with the increase of defect states, indicating the enhancement of photon energy absorption associated with the resonance exciton effect. In the future, this finding can be an alternative material for cheaper and renewable commercial rGO films and provide insight into the application of rGO-like films in many optoelectronic devices with a simple deposition method.