Dye-sensitized solar cells based on nanoparticle-decorated ZnO/TiO₂core/shell nanorod arrays

Nanoparticles (NPs) decorated ZnO/TiO2 core/shell nanorod arrays were fabricated on transparent conductive glass substrates by sequential plasma deposition and post-annealing processes for dye-sensitized solar cells (DSSCs) applications. The NPs decorated ZnO/TiO2 nanorods were composed of single-crystalline ZnO nanorods, homogeneously coated thin TiO2 shells and entirely covered anatase TiO2 NPs. The photocurrent density of the composite electrode was largely enhanced due to the enlarged surface area, the dark current was suppressed and the open-circuit voltage was increased because of the energy barrier formed at the interface between the ZnO core and the TiO2 shell. The increased photocurrent and open-circuit voltage led to an improvement of twice the energy conversion efficiency.