NANOCRYSTALLINE OXIDE SEMICONDUCTORS FOR DYE-SENSITIZED SOLAR CELLS

The search for renewable energy that is sustainable, inexpensive and environmentally friendly has led researchers to solar cells that convert sunlight to usable electric power. Dye-sensitized solar cells (DSSCs) have attracted extensive research attention due to low fabrication cost and high efficiency that is comparable to amorphous silicon solar cells. Further developments in lowering the cost and increasing the energy conversion efficiency require the discovery of new materials. In this chapter, I will review the work from our group on wide-bandgap oxide semiconductors for the DSSC application over the last several years. Nanostructured composites made up of anatase TiO₂ nanoparticles and single crystalline anatase TiO₂ nanowires have been used for the photoanode in order to achieve both high surface area and rapid electron transport rate. New promising oxide semiconductors such as Zn₂SnO₄ have also been demonstrated. On the counter electrode side, which should efficiently reduces tri-iodide to iodide at minimum energy loss and thus complete the circuit, mesoporous Nb-doped TiO₂ has been introduced for supporting Pt nanoparticles to control their size and agglomeration, and a reduced charge transfer resistance has been achieved.