A team of Australian and US researchers has set a new solar cell efficiency record when their multi-cell array achieved an efficiency of 43 per cent beating the previous record by 0.3 per cent.

Professor Martin Green of the University of New South Wales, leading the record breaking effort, said that only a fraction of the energy from the sunlight that falls on the cell is converted to electricity.

He said that sunlight is made up of small particles of light with different energy. To create electricity each photon of light must have enough energy to free an electron inside the solar cell, however if the energy of the photon is low, no electrical current is created as the photon just bounces off the cell, he added.

He added that a standard cell can respond to photons only above an energy threshold.

Silicon has a low energy threshold which allows most wavelengths of energy to free an electron, but at the same time silicon cells are not efficient in converting short wavelengths such as blue light, he said.

However, cells made of material with lower threshold are not as efficient converters are cells that are matched to that colour, according to Green.

To achieve a higher rate of conversion, the researchers used five types of solar cells than individually matched different wavelengths of light with each cell having the maximum efficiency to a particular colour.

With the use of filters, the researchers split the incoming light into different wavelength bands which were then used with different cells.

The researchers developed a cell that efficiently coverts red light into electricity which they combined with cells that had worked well for other wavelength ranges. With this configuration they were able to significantly improve the overall efficiency of conversion.

The other four cells were developed in the US by the National Renewable Energy Laboratory and Emcore Corporation.

The previous world record of 42.7 per cent was set using the four cells in combination with a cell developed at the University of Delaware.

Though the new design is very efficient, the flip side is it is expensive to produce.

Green who is next focusing on improving the efficiency of single silicon cells says there will always be a trade off with the cost of efficient electricity conversion and commercial efficiency.

He added the job of researchers is to improve the efficiency of silicon cells as single cells work out cheaper than five cells.