Todays MIT's Technology Review has an interview with Michael Gratzel, the Swiss inventor of the dye-sensitized solar cell (DSSC). The cells are now in limited production by Konarka, based in Lowell, MA USA, primarily for the military. Konarka has just announced a 25-megawatt facility for a foil-backed, dye-sensitized solar cells, by G24innovations ltd. in England, based on a Konarka license.
Gratzel said that silicon cells have about twice the efficiency of DSSCs, but DSSCs operate more efficiently in the early morning and in the evening and it efficiency is not affected by temperature. As a result the DSSC is 20% or 30% less efficient than silicon cells. The main advantage of DSSC is that a factor of 4 or 5 (lower in cost than silicon) is realistic.
Their is more to the interview, so please read the article.