Sustainability of Organic Dye-Sensitized Solar Cells: The Role of Chemical Synthesis

The synthesis of a novel and efficient pi-extended D-A-pi-A organic sensitizer (G3, eta = 8.64%) for dye-sensitized solar cells has been accomplished by applying the green chemistry pillars, aiming at overriding traditional routes involving organometallic intermediates with innovative synthetic strategies for reducing the waste burden and dye production costs. It has been demonstrated that the obtainment of a complex target sensitizer can be exclusively pursued via direct arylation reactions. Green metrics comparison with those of a traditional synthetic pathway clearly indicates that the new approach has a lower environmental impact in terms of chemical procedures and generated wastes, stressing the importance of the synergy between the molecular design and the synthetic plan in the framework of environmentally friendly routes to back up sustainable development of third-generation photovoltaics. Additionally, the stability of the G3-based photovoltaic devices was also investigated in aging tests on large area devices, evidencing the excellent potentialities of the proposed structure for all practical applications involving inorganic semiconductor/organic dye interfaces.