Thin Film Organic Solar Cells: Theoretical and Experimental Band Gap Energy Calculations.*

We analyze here different organic thin films with potential use for solar cells. We calculate the molecular orbitals and we obtain the band gap. We notice that the added zwitterions diminish the band gap of the film, making better solar cells. The two solar cells are obtain by depositing on the substrate of choice two different polymers, polyaniline and poly(3-hexylthiophene-2,5-diyl), and the zwitterion: p-benzoquinone monoamine. The band gap is theoretically calculated by using HyperChem package and obtained experimentally via Halogen and Deuterium spectra measurements. The I-V curves show that these films have great potential as efficient solar cells, as shown by the calculated ideality factor.