Photovoltaic cells (PVCs) use semiconductors to convert light energy into electrical current and are regarded as one of the key technologies towards a sustainable energy supply. The current PVCs supplying power conversion efficiencies of 10–20%. However, their poor absorbing properties and the difficulty in producing uniform thin films over large area substrates make the manufacturing processes quite costly. Further, most current PVCs harvest solar energy with a wavelength below 1.1 micron, though almost 50% of the sun power reaching the earth is in the infrared (IR) regime, and the power conversion efficiency could be improved with the use of the IR portion above 1.1 micron. This paper proposes the development of radically new nanostructures and molecular materials for the production of innovative solar cells, called excitonic solar cells (XSCs), competitive with traditional energy sources. The goals of the research are to develop XSCs using of semiconductor quantum dots (QDs) as light harvesting units, with a fine tuning of the optical cross section and of the band gap in the IR regime. To design molecular relays (MRs) that connect the QDs to electron conductor materials, the MRs should enable carriers’ transport and good adhesion to the electron-transport nanostructures. Moreover, a specifically designed n-type semiconductors will be developed, such as ZnO or TiO2 nanofibers, with architecture, morphology and surface structure suitable to maximise the efficiency of the charge transfer processes at the QD. The competitive cost-efficiency ratios of the materials used in this research will be improved, developing efficient synthesis approaches and surface functionalization to enable reliable, large scale applications of XSC devices. The significance of this research is the integration of innovative materials in XSC devices to be used as environmentally clean, renewable electric power sources, paving the way for short-, medium-, and long-term applications.