Combined experimental and theoretical study of conjugated ferrocene semiconductors and the effect of doping on their opto-electrical and structural properties

Abstract
In this work it is reported the semiconductor behavior of ferrocene-doped films prepared by vacuum deposition. The ferrocenium hexafluorophosphate (I) was chemically doped with the 2,6-Dihydroxyanthraquinone (a) and the 2,6-Diaminoanthraquinone (b) and the corresponding semiconductor films were deposited. The structure and morphology of the films were characterized by IR spectroscopy, scanning electron microscopy (SEM), and X-ray diffraction analysis. The correspondent data (absorbance, transmittance, and optical and transport energy gap) were collected from UV-vis studies. Theoretical calculations by means of Gaussian16 software and all the involved species were geometrically optimized. Theoretical and experimental IR spectra were compared to verify the presence of the main functional groups of the doped semiconductors. Based on the calculations of HOMO-LUMO and band gap results, the doped films can be used as p-type semiconductor. A change on J-V curve under illumination conditions was observed. The conductivity for Ia is of 2.65 × 102 S cm−1 and for Ib is of 1.31 S cm−1, those values increased with the incident photon energy to 4.2 × 102 S cm−1 and 13.28 S cm−1 respectively. A photosensitivity for Ib of 916% and for Ia of 58% were obtained. The EQE spectra is close to a square shaped curve with an ∼0.87 mean value, with oscillations. These results indicate that the obtained semiconductors doped with anthraquinone derivatives, could be used in several optoelectronic devices such as solar cells and photosensors.