HY-SUNLIGHT · Optical properties of hybrid organic/inorganic nano-particles for photovoltaic applications: toward a predictive computational approach

Hopes for a new generation of photovoltaic technology (PV) which may overcome the limitations of the present semiconductor-based technology are based on organic materials, due to their light weight and broad absorption spectrum. In this respect, a special role is played by hybrid organic/inorganic nano-particles. Typical hybrid PV (HPVs) are composite films of semiconductor nano-particles (quantum dots) coupled to organic cromophores active in the visible range. Despite the strong efforts to improve efficiency and stability of HPVs to outperform standard inorganic cells, at present no theoretical/computational approach, going beyond heuristic models, is available to reliably describe the optical excitation of HPVs. These complex systems are untractable by present computational tools due to the very different nature of light-matter interactions in the different segments, leading the respective optical excitations to cover very different length scales. This situation is particularly unsatisfactory as the optical properties of hybrid organic/inorganic nano-particles may find ground-breaking applications in other applied field, notably nano-medicine and biology. The goal of the present proposal is to build the theoretical/computational background for a quantitative modeling of the light response of HPV. The specific objectives are i) a methodological advancement in HPV description, namely, the development of a genuine multi-scale computational method, based on a 'hybrid' Configuration Interaction approach, suited to deal with nano-hybrid systems; the new method should be able to describe excitations unique to, and delocalized over, the hybrid system in a nearly parameter-free approach, comparable to standard quantum-chemistry approaches which would not be applicable in this case; ii) the application of the new scheme to selected proto-typical systems of interest for HPV, and the conceptualization of the microscopic mechanisms of their optical properties.