Introduction
1 Inorganic solar cells
2 Dye-sensitized solar cells (DSSC)
2.1 Cells based on dyes
2.2 Grätzel's cells
   2.2.1 Materials
   2.2.2 DSSCs' problems
   2.2.3 Today research
   and development
       a- Two dyes
       b- Solid-state DSSCs
       c- Other semicondutors
       d- Multilayer