Enhanced Efficiency in Dye-Sensitized Solar Cells with Shape-Controlled Plasmonic Nanostructures

In this work, we demonstrate enhanced light harvesting in dye-sensitized solar cells (DSSCs) with gold nanocubes of controlled shape. Silica-coated nanocubes (Au@SiO2 nanocubes) embedded in the photoanodes of DSSCs had a power conversion efficiency of 7.8% relative to 5.8% of reference (TiO2 only) devices, resulting in a 34% improvement in DSSC performance. Photocurrent behavior and incident photon to current efficiency spectra revealed that device performance is controlled by the particle density of Au@SiO2 nanocubes and monotonically decreases at very high nanocube concentration. Finite difference time domain simulations suggest that, at the 45 nm size regime, the nanocubes predominantly absorb incident light, giving rise to the lightning rod effect, which results in intense electromagnetic fields at the edges and corners. These intense fields increase the plasmonic molecular coupling, amplifying the carrier generation and DSSC efficiency.