What are the PV cell types?
We can classify all photovoltaic technologies in three generation. Some of these technologies are listed below:
A. First Generation Solar Cells
a. Single Crystal Solar Cells
b. Multi Crystal Solar Cells
B. Second Generation Solar Cells
a. a-Si thin film solar cells
b. mc-Si solar cells
c. CdTe solar cells
d. CIS and CIGS solar cells
C.Third Generation solar cells
a. Nanocrystal based solar cells
b. Polymer based solar cells
c. Dye sensitized solar cells
d. Concentrated solar cells
A. First Generation Solar Cells is the oldest and the mostly common used technology type due to high efficiencies. 1 generation solar cells are produced on wafers. Each wafer can supply 2-3 watt power. To increase power, solar modules, which consist of many cells, are used. As seen in the list, generally there are two types of first generation solar cells. They differ by their crystallization levels. If the whole wafer is only one crystal, it is called single crystal solar cell. If wafer consist of crystal grains, it is called multi-crystal solar cell. Anyone can see the boundaries between grains on the solar cell. Although efficiency of mono crystal solar cells is higher than multi-crystal solar cells, production of multi-crystal wafer is easier and cheaper. So they are competitive with mono crystals
B. Second Generation Solar Cells are thin film solar cells. Despite their efficiencies are lessthan 1st generation, their costs are also less than 1st generation. In addition they have an advantage in visual aesthetic. Since there is no fingers in front of the thin film solar cells for metallization, they are much more applicable on windows, cars, building integrations etc. These thin films can also be grown on flexible substrates. So second generation solar cells are applicable on textile products or on foldable devices. As an advantage of thin film solar cells, they can be growth on large areas up to 6 m2. However wafer based solar cell can be only produced on wafer dimensions. The second generation solar cells include amorphous Si (a-Si) based thin films solar cells, Cadmium Telluride/Cadmium Sulfide (CdTe/CdS) solar cells and Copper Indium Gallium Selenide (CIGS) solar cells.
C. Third Generation Solar Cells are novel technologies which are promising but not commercially proven yet. Most developed 3rd generation solar cell types are dye sensitized and concentrated solar cell. Dye sensitized solar cells are based on dye molecules between electrodes. Electron hole pairs occur in dye molecules and transported through TiO2 nanoparticles. Although their efficiency is very low, their cost is also very low. Their production is easy with respect to other technologies. Dye sensitized solar cells can have variable colors. Concentrated PV solar cell is another promising technology. Main principle of concentrated cells is to concentrate large amount of solar radiation on to a small region where the PV cell is located. The amount of semiconductor material, which might be very expensive, is reduced in this way. In this system a perfect optical system should be integrated. Concentration levels starts from 10 sun to thousands suns. So, total cost can be lower than conventional systems. CPV s are promising technologies for near future.