Third generation photovoltaic cell
Third generation photovoltaic cell, also called advanced thin-film photovoltaic cell, is a range of novel alternatives to "first generation" (silicon p-n junction or wafer solar cells) and "second generation" (low-cost, but low-efficiency thin-film) cells. It is an even more advanced version of the thin-film cell.
Several new solar cell or photovoltaic technologies, have been proposed or discovered in recent years, due to extensive research and development with a focus on finding more efficient alternatives to traditional silicon solar cells. Research and development in this area generally aims to provide higher efficiency and lower cost per watt of electricity generated. The main criterion Martin Green gives is that the technology aims for extremely high efficiency, "double or triple the 15-20% range currently targeted." The third generation is especially concerned with exceeding the theoretical Shockley-Queisser limit of around 31% for single-junction solar photovoltaic efficiency.
The third generation is somewhat ambiguous in the technologies that it encompasses, though generally it tends to include, among others, non-semiconductor technologies (including polymer cells and biomimetics), quantum dot, tandem/multi-junction cells, intermediate band solar cell , hot-carrier cells, upconversion and downconversion technologies, and solar thermal technologies, such as thermophotonics, which is one technology identified by Green as being third generation.
It also includes:
- Silicon nanostructures
- Modifying incident spectrum (concentration).
- Use of excess thermal generation (caused by UV light) to enhance voltages or carrier collection.
- Use of infrared spectrum to produce electricity at night.
Reasons for change
Traditional solar cells have had several major drawbacks over the last thirty years. They are expensive, fragile, and are inefficient on several levels. A main hindrance has been that the key ingredient, refined silicon, has become more expensive, which makes it difficult to reduce the cost of the cells. Silicon also has many physical barriers which limit the efficiency and uses of traditional solar cells.
Nanotechnologists are finding solutions to make solar cells cheap, flexible, compact, light weight, efficient and non-intermittent (to convert infrared light). They are able to do this by finding alternative chemicals and materials to harness solar energy.
Expected market shift
There has been a lot of hype circling around the possibilities of advanced solar technology in recent years. Major companies and investors such as Google, have invested hundreds of millions of dollars towards this new generation of solar power. They are counting on the likely possibility that the new technologies could compete with not only traditional solar cells, but more importantly with fossil fuels and nuclear energy (to reach and surpass grid parity). This would revolutionize our energy market; as said, in order for this to happen, third generation solar cells will need to be more efficient and cheaper.
The new materials that solar energy can be harnessed with is one of the most exciting elements of the new technology. The flexible and lightweight physical characteristics of the different types of third generation solar cells makes many new applications possible.
There is the possibility that solar cells could be integrated into clothing which would allow us to have personal wireless power without batteries.
Another plausible application could be a type of automobile paint that is blended with polymer solar cells. This could help maintain the lightweight form of a solar car while still providing ample energy to power it.
Types of third generation solar cells
While the new solar technologies that have been discovered center around nanotechnology, there are several different material methods currently used.
CdTe (second generation)
CIGS (copper indium gallium selenide) (second generation)
- Band gap
- Grid parity
- Low-cost solar cell
- Optical concentration
- Organic electronics
- Printed electronics
- Solar Cell
- ↑ Green, M.A., Third generation photovoltaics: Ultra-high conversion efficiency at low cost. Progress in Photovoltaics: Research and Applications, 2001. 9(2): p. 123-135. doi:10.1002/pip.360
- ↑ Weiming Wang, Albert S. Lin, Jamie D. Phillips (2009). [Expression error: Missing operand for > "Intermediate band photovoltaic solar cell based on ZnTe:O"]. Appl. Phys. Lett. 95: 011103.
- ↑ Green, Martin (2003). Third Generation Photovoltaics: Advanced Solar Energy Conversion. Springer Science+Business Media. ISBN 3540401377.
- ↑ UNSW School for Photovoltaic Engineering. "Third Generation Photovoltaics". http://www.pv.unsw.edu.au/Research/3gp.asp. Retrieved 2008-06-20.