- Category: Technology
01 Aug 2012
- Published on Wednesday, 01 August 2012 08:00
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A solar cell using quantum dots developed by researchers at the University of Toronto and the King Abdullah University of Science and Technology has been certified as reaching a record efficiency of 7 percent.
Quantum dots are semiconductors that are only a few nanometers in size. They are considered promising materials for the next generation of solar cells because they can be used to harvest electricity from the entire solar spectrum.
Most current solar devices harvest visible light and convert it to energy, but this is just a fraction of the available light that hits the earth. Developing a solar cell that can absorb more than just visible light could increase the amount of energy that it generates.
The team from the University of Toronto and King Abdullah University developed a colloidal quantum dot film for a solar cell which they found showed a 37 percent increase in efficiency over previous versions.
To improve efficiency, the researchers reduced the number of “traps” for electrons which were associated with the poor surface quality of previous films using a technique dubbed as “hybrid passivation.”
They introduced small chlorine atoms immediately after synthesizing the dots to “patch” the surfaces between the dots to allow smoother flow of electrons for a greater current. They also used short organic linkers to bind the quantum dots in the film closer together to achieve dense films with closer packed nanoparticles. The researchers’ manufacturing techniques also lead to CQD films that can be created quickly and at a low cost, similar to paint or ink. Solar cells using this material could be fabricated on flexible substrates similar to the same way newspapers are printed. – EcoSeed Staff