Solar Cells  
A solar cell or photovoltaic cell is a semiconductor device that converts light directly into electricity by the photovoltaic effect. 
There are different types of photovoltaic cells: 
Single crystal silicon PV cells are manufactured using a single-crystal growth method and have commercial efficiencies between 15 % and 18 %. 
Multicrystalline silicon cells, usually manufactured from a melting and solidification process, are less expensive to produce but are marginally less efficient, with conversion efficiencies around 14 %. 
PV cells made from silicon ribbons demonstrate an average efficiency around 14 %. 
Thin film cells, constructed by depositing extremely thin layers of photovoltaic semi-conductor materials onto a backing material such as glass, stainless steel or plastic, show stable efficiencies in the range of 7 % to 13 %. Thin film materials commercially used are amorphous silicon (a-Si), cadmium telluride (CdTe), and copper-indium-gallium-diselenide (CIGS). 
Commercially available thin film modules: 
- Are potentially cheaper to manufacture than crystalline cells 
 - Have a wider customer appeal as design elements due to their homogeneous appearance 
 - Present disadvantages, such as low-conversion efficiencies and requiring larger areas of PV arrays and more material (cables, support structures) to produce the same amount of electricity
 
Source: IEA PVPS 
  Solar Modules  
A solar module is a commercial product formed by solar cells.