Distance dependence of plasmon-enhanced photocurrent in dye-sensitized solar cells

(Graph Presented) We have fabricated titanium dioxide based dye-sensitized solar cells that incorporate corrosionprotected silver nanoparticles as plasmonic optical elements of the photoelectrode. The thickness of the TiO ₂ layer separating the dye from the nanoparticles has been systematically varied using atomic layer deposition. Over the range of TiO ₂ coating thicknesses examined (2 to 8 nm) there is clear enhancement of the dye extinction when plasmonic particles are present, with the enhancement increasing as the TiO₂ thickness decreases. The optical enhancements translate into photocurrent enhancements, with the best cells (thinnest TiO₂ coatings) showing 9-fold current enhancements under optimal monochromatic illumination. Preliminary experiments indicate that substantially larger optical enhancements are achievable with even thinner dye/particle separation layers, suggesting that even greater photocurrent enhancements may be achievable.