Scientists achieve new record for solar cell efficiency

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Sydney, August 27 (ANI): A team of Australian and US researchers has set a new record for solar cell efficiency, by developing a multi-cell array that achieved an efficiency of 43 percent, beating the previous world record by 0.3 percent.

According to a report by ABC News, University of New South Wales (UNSW) Professor Martin Green, who led the record-breaking effort, said that solar cells only convert a fraction of the energy from sunlight into electricity.

"Sunlight is made up of little particles and these particles have different energy," he said.

To create electricity, each photon of light must have enough energy to free an electron inside the solar cell.

If the energy is low, the photon will bounce off the solar cell, and no electrical current will be created.

"A standard cell can respond to photons of certain energy and above, but not below," said Green, who heads the UNSW ARC Photovoltaics Centre of Excellence.

Silicon, which is used in most solar cells, has a low threshold ensuring most wavelengths of visible light will free an electron.

But, they are inefficient converters of short wavelengths such as blue light.

"Cells that have a lower threshold don't convert the light as efficiently as a cell that is matched to that colour," said Green.

To achieve a higher rate of conversion, the researchers used five different solar cell types matched to different wavelengths of light.

"Each cell has the maximum efficiency for one particular colour," said Green.

Using filters, the solar cell splits the incoming light into its different wavelength bands and sends it to the different cells.

The UNSW researchers developed a cell that efficiently converts red light into electricity.

"Our cell works efficiency over the red end of the solar spectrum," said Green. "We combined it with cells that had done well over other wavelength ranges, so in that way we were able to improve efficiency," he added.

The other four cells were developed by two US groups based at the National Renewable Energy Laboratory and Emcore Corporation.

Instead of silicon, these cells used combinations of gallium, indium, phosphorus and arsenic.

The previous world record of 42.7 percent was set using these four cells in combination with another cell from the University of Delaware. (ANI)

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