Recent developments in solid-state dye-sensitized solar cells.

The dye-sensitized solar cell, developed in the 1990s, is a non-conventional solar technology that has attracted much attention owing to its stability, low cost, and device efficiency. Power-conversion efficiencies of over 11% have been achieved for devices that contain liquid electrolytes, whereas solid-state devices that do not require a liquid electrolyte display an overall efficiency of 5%. Improvement of the efficiency of solid-state dye-sensitized solar cells requires optimization of their various components, such as the hole-transport material, sensitizer, mesoporous TiO2 film, and the blocking layer. This Minireview highlights the current state of the art and future directions of solid-state dye-sensitized solar cell technology.