  Quantum dot sensitized solar cells are among the new generations of solar
cells that have attracted much attention. Theoretical and simulation studies
have predicted high efficiency for these cells so that in the future, these
cells could be an excellent alternative to silicon solar cells. Other
advantages of these cells are their ease of fabrication and cheaper
manufacturing methods than existing cells. This paper's main idea is to
simulate the effect of different quantum dots on the optical and electrical
characteristics of these cells and, in particular, the efficiency. We then
simulated the effect of simultaneous sensitizing by different quantum dots, and
we observed that the cell's light absorption and the efficiency in simultaneous
sensitizing, increased. Then we experimentally studied one of the cells that
give the best simulation result (PbS/CdS co-sensitized). We deposited the
quantum dots on transparent TiO2, and we obtained the light absorption,
efficiency, and other characteristics of cells. Further, we investigated the
effect of cobalt sulfide as the counter electrode in PbS/CdS, instead of
platinum and gold, and we found that the efficiency has increased.
