Four Generations of Solar Cells

As solar photovoltaic (PV) technology advances, solar cells, the electricity-producing heart of the solar panel, have been divided into four categories or generations. These represent a sort of timeline of solar innovations, separated by characteristics such as semiconductor material, application, and stage of development.

1st Generation

The first generation of solar cells is currently the most commercially widespread, as well as the oldest. These are conventional, silicon wafer solar cells. They use thinly sliced wafers of silicon as a semiconductor, that part of the solar cell that absorbs photons, exciting its electrons into creating employable electric current. Silicon solar cells currently control roughly 80% of the PV market due to their relatively high conversion efficiency, although that is expected to change as second generation solar cells become cheaper and more efficient.

2nd Generation

Second generation photovoltaics include thin-film and building integrated (BIPV) technology. These solar cells are thinner, more flexible and more inexpensive than their first generation counterparts. Here the types of semiconductor materials broaden, from amorphous silicon (a-Si) to cadmium telluride (CdTe) and copper-indium-gallium-selenide (CIGS). Second generation, thin-film solar cells are expected to take over market dominance from first generation solar cells within five to ten years. So far their flexibility and diversity of available applications has not been enough to overtake conventional silicon solar cells, whose conversion efficiency often doubles that of thin-film products on the market. Laboratory testing has shown efficiencies equal to or greater than silicon solar cells, but manufacturers have not been able to transfer these numbers to market as of yet.

3rd Generation

Third generation solar cells are getting ever closer to market, but are still mostly in the laboratory/testing phase. Technologies include plastic (polymer) solar cells, photoelectrochemical solar cells and organic dye-sensitized cells. Third generation solar cells promise incredibly cheap production costs and applications -- to the point of solar paint and homemade solar cells. Barriers at this point include fast degradation of the cells and very low efficiencies. Just recently the first 10-percent-efficient dye-sensitized solar cell was tested in laboratory. Nonetheless, third generation solar cells are expected to have a very promising future.

4th Generation

Fourth generation solar cells are considered the future of solar technology. Still years off, this category includes such cutting edge technology as quantum dots and nanowires.

Solar Cell Components / Four Generations