Recombination barrier layers in solid-state quantum dot-sensitized solar cells

By replacing the dye in the dye-sensitized solar cell design with semiconductor quantum dots as the light-absorbing material, solid-state quantum dot-sensitized solar cells (ss-QDSSCs) were fabricated. Cadmium sulfide quantum dots (QDs) were grown in situ by successive ion layer adsorption and reaction (SILAR). Aluminum oxide recombination barrier layers were deposited by atomic layer deposition (ALD) at the TiO₂/hole-conductor interface. For low numbers of ALD cycles, the Al₂O₃ barrier layer increased open circuit voltage, causing an increase in device efficiency. For thicker Al₂O₃ barrier layers, photocurrent decreased substantially, leading to a decrease in device efficiency.