Design of novel organic compounds for the development of solar energy conversion devices

In the last decades, the global perception of the energy crisis has encouraged the research to the development of novel technologies from renewable sources. In particular, great emphasis has been devoted to solar energy conversion devices. While the international photovoltaic market is still dominated by silicon-based solar cells, perovskite solar cells (PSCs), dye-sensitized solar cells (DSSCs) and luminescent solar concentrators (LSCs) are considered as promising alternative technologies in terms of improved manufacturability and for the possibility to reduce the costs and enhance the light trapping of high efficiency silicon-based solar cells. Additionally, in the last years PSCs have become potentially competitive to silicon-based solar cells for their high efficiency, while DSSCs and LSCs have the great advantage to work under diffused light and they can be easily incorporated into the building-integrated photovoltaics (BIPV). Despite the attractive features, these technologies still present some efficiency and instability issues related to their components. For this reason, the design of novel materials for highly performant and stable solar energy conversion devices has become an attractive and challenging issue involving worldwide researchers. In this context, this thesis addresses the design of novel organic compounds to be employed in PSCs, DSSCs and LSCs. In particular, the design of novel organic i) hole transport materials (HTMs) in PSCs, ii) sensitizers in DSSCs and iii) fluorophores in LSCs has been carried out with the aim of contributing to the development of potentially more efficient devices. To this end, state-of-the-art Density Functional Theory (DFT) and Time Dependent Density Functional Theory (TDDFT) methods represent powerful tools for the discovery of promising materials in the solar energy field. Here, they have mainly been applied for the prediction of the most relevant physical-chemical properties of the designed compounds and for the investigation of the structure-property relationships. In such a way it is possible to make an assessment of their suitability to be employed in the aforementioned devices. The outcomes of these studies would provide the fertile ground for future projects that will hopefully contribute to accelerate the research in this field. Indeed, the increased knowledge on the behavior of these materials is the key for boosting the development of solar energy conversion devices in the near future.