Design, fabrication, and characterization of donor-acceptor molecular systems for photo-induced charge separation
Photoinduced charge generation and separation in donor-acceptor systems depend on the electronic properties of the molecular components, as well as on their intermolecular
interactions and organization in the solid state. This work focuses on the π-conjugated S,N-heteroacene derivative SN3a-DCV and its interactions with the donor polymers
P3HT and PM6. The electronic and optical properties of SN3a-DCV were evaluated using DFT and TD-DFT calculations, while its structural properties and tendency to form
crystalline domains were investigated experimentally. The molecular system was studied in different material configurations, including molecular crystals, thin films, donor-
acceptor blends, and organic photovoltaic (OPV) devices. Structural, optical, morphological, and electrical characterization was used to evaluate the effects of SN3a-DCV on the organization and charge-transport properties of the resulting systems. In lateral devices, the P3HT/SN3a-DCV and PM6/SN3a-DCV blends showed changes in electrical conductivity, photoconductivity, and activation energy compared with the corresponding donor polymers. SN3a-DCV was also incorporated as a third component into photovoltaic blends to evaluate its effects on the morphology and electronic properties of the active layers. The results are discussed in terms of the relationship between molecular structure, intermolecular interactions, material organization, and charge-transport and photoinduced electronic properties in donor-acceptor systems.