Assessment of new gem-silanediols as suitable sensitizers for dye-sensitized solar cells

Four novel gem-silanediol-containing organic dyes featuring a highly conjugated backbone have been synthesized in order to investigate their potential as active materials for photovoltaics. After spectroscopic characterization, the compounds showing the best light harvesting and electrochemical properties were applied as sensitizers in dye-sensitized solar cells (DSSCs). Interestingly, photovoltaic cells built using the new silanediol dyes showed low power conversion efficiencies (η), comparable to those obtained with silicon-based sensitizers having simple azobenzene moieties as the light-harvesting units. Such values are mostly due to unsatisfactory photocurrent densities; a computational study suggested that the latter can be justified considering the insufficient degree of charge transfer taking place during photoexcitation of the silicon-containing sensitizers, which is likely to make electron injection into the TiO2 layer less efficient