Photovoltaics is, to date, the most promising of all technologies to produce clean and renewable energy. Currently in use silicon-based solar cells have reached power conversion efficiencies as high as 26%, but their fabrication involves expensive and contaminating processes. Moreover, further improvement of their efficiency is restricted to around 30% by the so-called Shockley-Queisser (SQ) limit. Potential solutions to these problems may involve moving from inorganic to organic materials. In this sense, organic solar cells (OSCs) represent a promising alternative to replace silicon because of their low cost, flexibility, and manageable nature. Single-material organic solar cells (SMOSCs), a particular class of OSCs in which the donor and acceptor materials are covalently linked, are particularly attractive because of their facilitated fabrication processes, improved stability, morphology, and reproducibility. On the other hand, to enhance the efficiency beyond the theoretical SQ limit, the use of sensitizing singlet fission (SF) chromophores has been proposed. These materials are able to form two triplet excitons from a single absorbed photon, thus raising the External Quantum Efficiency of solar cells up to 200%. The aim of the Full-Fission action is to combine the potentialities of both approaches to fabricate efficient SMOSCs that incorporate fullerenes functionalized with SF moieties as the active layer. The Full-Fission action is conceived as a holistic approach that will combine computationally-assisted materials design, synthesis, and device fabrication in an interconnected and interdisciplinary project developed by a researcher with experience in all these disciplines.