Resarch and devolpment of high efficiency, low-cost nano-crystalline solar cells

Among renewable energy sources, solar (especially photovoltaic, PV) systems stand out as a viable solution to address the growing world energy demand, while mitigating environmental effects and contributing to secure some of the 2030 Sustainable Development Goals prescribed by United Nations. The current market for ground-based PV applications is largely dominated by Silicon and, to a lesser extent, inorganic thin films (based on CdTe and Cu(In,Ga)Se2) solar cells, with power conversion efficiencies (PCEs) not exceeding 25%. Potentials for further improvements of the PCE values of such cells are however, limited by fundamental physics mechanisms and technological constraints. A promising strategy to overcome these limitations goes through the development of nanostructured solar cells, in which reduced volumes of nano-crystalline semiconducting materials are employed, enabling to exploit novel and more efficient physical mechanisms for absorption and conversion of solar power into electricity at lower costs (III-generation PV). The Semiconductor Physics and Technology (SPT) group at the Dept. of Innovation Engineering of the Univ. of Salento is actively engaged in this research field, aiming at developing next generation of highly efficient, low-cost nano-crystalline solar cells. To this purpose, the group studies the nanoscale synthesis of quasi 1-dimensional (so-called nanowires) and 2-dimensional (graphene-like) materials by advanced deposition methods, such as metalorganic vapor phase epitaxy (MOVPE), chemical vapor deposition ((CVD) and molecular beam epitaxy (MBE). The principles and applications of such methods for the growth of nanowire complex structures and (multi)layered 2-dimensional materials will be described, along with examples of as-synthesized structures and their potentials for fabrication of innovative high PCE solar cells.