Solar cell record efficiency set by European scientists

Researchers achieved 44.7% efficiency, which is a major step towards further reducing the costs of solar power

(Pic: Soitec)

By Nilima Choudhury 

A new world record for the conversion of sunlight into electricity using solar cells has been set after only three years of research.

Europe’s largest solar energy research centre Fraunhofer ISE, Soitec, which manufactures the cells, and research organisations CEA-Leti and the Helmholtz Center Berlin measured a new record efficiency of 44.7%.

This is a major step towards reducing further the costs of solar electricity and continues to pave the way to the 50% efficiency road-map.

Speaking to RTCC, Frank Dimroth, department head and project leader in charge of this work at Fraunhofer ISE, said: “The cells that we are developing are used in concentrator photovoltaic (CPV) systems used in solar power plants to produce several megawatts of power in one place.

“Higher efficiency means that the overall system, which consists of lenses, frames, tracking units, will produce more electrical energy. So only one component (the solar cell) is more efficient but the overall system produces more energy and this lowers the overall cost quite significantly.”

Dimroth is optimistic his team can further increase the cell efficiency by 1-2% by the end of the year.

Most solar panels are actually composed of photovolatic cells stacked on top of each other.

The problem is that a lot of energy gets lost when the electrons hit the connective or “junction cells” that sit between each photovoltaic cell.

To reduce the loss of energy and thereby guaranteeing high efficiency records, the team developed a new technology.

“A new procedure called wafer bonding plays a central role,” said Dimroth.

“With this technology, we are able to connect two semiconductor crystals, which otherwise cannot be grown on top of each other with high crystal quality. In this way we can produce the optimal semiconductor combination to create the highest efficiency solar cells.”

However, CPV technology is not without its critics.

Finlay Colville, vice president of Solarbuzz told RTCC that CPV’s long term impact on the renewable energy industry is yet to be gauged.

“CPV has always received considerable R&D funding, but has yet to form any meaningful competition to standard silicon solar cell production.

“However, there are not yet enough firm datapoints to suggest that CPV will have any appreciable impact on the widespread PV [photovoltaic] industry in the next three to five years.

Dimroth is confident his team’s new technology to capture the energy generated by CPV solar cells can help to increase the uptake of solar power in the future.

“Today, CPV can produce electricity in sun-rich countries for approximately 10 cent/kWh and we hope that this can be reduced in the future.

“Lowering of the electricity generation cost is of course one of the most important tasks in PV research. This is important to ensure that the energy transition process from fossil fuels to renewables can be affordable.”

The research team did not say when the cell could be put into production.

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