Quantum Dot−Dye Bilayer-Sensitized Solar Cells: Breaking the Limits Imposed by the Low Absorbance of Dye Monolayers

Here, we present a new DSSC design, consisting of sequential QDs and dye sensitization layers, that opens the path toward high optical density DSSCs that cover a significant part of the solar spectrum. The new configuration is enabled by the application of an amorphous TiO₂ layer between the two sensitizers, allowing both electron injection from the outer absorber and fast hole extraction from the inner sensitizing layer. Utilizing two sensitizing layers, we obtain a 250% increase in cell efficiency compared to a QD monolayer cell.