All PV- modules contain a number of layers from the light-facing side to the back:
Protection Layer Usually made from glass, though in thin-film modules this can also be transparent plastic.
Front Contact The electric contact at the front, has to be transparent, as otherwise, light would not get into the cell.
Absorption Material The heart of the module is the layer where the light is absorbed and converted into electric current. All materials used are semiconductors. In many cells, this is just one material, in most instances, silicon. However, in order to improve performance, there could be multiple layers of different materials. In addition, all layers are be doped. I.e. each layer is split further into an n-dopedand a p-doped zone. See below for more details on doping.
Metal back contact A conductor at the back completes the electric circuitry.
Laminate Film A laminate ensures that the structure is water-proof and isolated from heat.
Back glass This layer gives protection on the back side of the module. It may be glass, it may also be made of aluminum or plastic.
Connectors Finally, the module is fitted with connectors and cables, so it can be wired.