SnO₂ Transparent Printing Pastes from Powders for Photon Conversion in SnO₂ -Based Dye-Sensitized Solar Cells

Tin oxide (SnO₂ ) is the most attractive alternative to titanium oxide (TiO₂ ) with the aim of identifying a more positive conduction band material for dye-sensitized solar cells (DSCs). This study puts forward a protocol based on grinding, sonication, and centrifuge to generate transparent SnO₂ pastes to minimize light reflectance losses from the metal oxide. Under optimized conditions, a highly transparent film with substantially enhanced light penetration depth through active layer SnO₂ is realized for efficient light harvesting from two different commercially available powders (18 and 35 nm nanoparticle sizes). A ruthenium sensitizer (B11) and two organic sensitizers (NL3 and MK2) are shown to achieve higher or comparable photocurrent densities with SnO₂ relative to standard TiO₂ -based DSCs. SnO₂ -based DSCs show minimum recombination losses, comparable charge collection efficiencies, and minimal photovoltage losses relative to TiO₂ DSCs. Thus, the option of a transparent metal oxide, which can facilitate high photocurrents (>16 mA cm^-2 observed) and lower recombination rates than TiO₂ is an attractive material for DSC applications.