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New research is offering the potential to boost efficiency of solar cells by 100 percent. The typical solar cell efficiency can, according to Chemists Xiaoyang Zhu at the University of Texas at Austin, be increased from 30 percent to above 60 percent. This was shown in a study on semiconductor nano-crystals and so-called quantum dots.

A research’s team has been able to invent a technique to maximise the energy provided by the sun. A technology that will make us of the heat energy that is unfortunately wasted through the contemporary solar cells.

The conventional silicon solar cells can harness at its optimum efficiency roughly 31 percent of the energy provided by the sun. The low percentage is due to the fact that much of the energy striking the solar cells is too strong to be converted into electricity. The type of heat energy that is lost is in known as “hot electrons”.

If these hot electrons would be converted to electricity, it would theoretically be possible to reach a maximum energy efficiency of 66 percent. It would mean that new solar cells could be twice as effective as conventional solar cells.

Zhu, Professor of Chemistry and director of the Center for Materials Chemistry said that there are only some phases left to develop this ultimate solar cell. The steps that are required are;

1. The rate at which hot electrons cool down must be decreased.
2. The hot electrons must be collated and used before the energy is lost.

According to Zhu, quantum dots or semiconductor nano-crystals are the potential solutions available to concretize this “ultimate Solar Cell”

The first obstacle to slow down the process at which hot electrons get cooler can be achieved through semi-conductors nano-crystals. Its feasibility has already been shown by a research group at the University of Chicago in 2008.

The second phase of how to use these electrons has been discovered by Zhu’s team. They found that these hot electrons might actually be converted from photo-excited lead selenide nano-crystals to an electron conductor built of titanium dioxide.

According to Zhu, extracting hot electrons would make them more manageable. The conversion of hot electrons is not only a theoretical aim. It has experimentally been proven to work.

Zhu said that, they used quantum dots created of lead selenide. However, other materials would work as efficiently as well.

Moreover, Zhu said that this is only a scientific step ahead. He proclaimed that it will take some time until solar cells with 66 percent efficiency will be on the market. There are still a lot of engineering and science needed to perfection the technology.

For instance, there are additional hurdles like linking electrical conducting wires. This is another challenge for science. According to Zhu, extracting hot electrons at a rapid speed would require advanced wiring to prevent the wires from losing heat energy. It is necessary to minimize the loss of energy and maximizes the energy harness through the sun. This is how the ultimate solar cell can reach an efficiency of 66 percent.

Zhu goes to the extent of saying that “There is no reason that we cannot be using solar energy 100 percent within 50 years.” This would alleviate the environmental impacts associated with fossil fuel.

Source: Science Daily