High energy conversion efficiency and low cost are key features of modern solar cell devices. Leading solar manufacturing firms therefore persist in improving performance and reducing device costs to remain competitive.
Researchers at the University of New South Wales (UNSW), have recently developed an innovative method to dramatically improve the quality of low-grade silicon. This allows significant improvements to electrical efficiency and reduces the cost of solar panels. This breakthrough has attracted the interest of manufacturers, who foresee the opportunity of gaining a competitive edge through licensing UNSW’s technology.
The UNSW technology controls hydrogen atoms to compensate for structural defects in the silicon material. Structural defects and impurities in silicon create recombination centres which affect the final solar cell conversion efficiency. The introduction of hydrogen atoms into the atomic structure of silicon makes these defects electrically inactive. This is a well established technology. However, UNSW researchers have enhanced the effectiveness of this technology by devising a method to control the charge state of hydrogen atoms in silicon. As a result, they are able to control the hydrogen mobility and its capability to bond to defects. In doing so, this enables the use of cheaper, lower grade silicon to create highly efficient solar panels.
“We have seen a 10,000 times improvement in the mobility of the hydrogen and we can control the hydrogen so it chemically bonds to things like defects and contaminants, making these inactive,” says Scientia Professor Stuart Wenham.
According to Prof. Wenham, the process allows low-quality silicon wafers to perform better than higher quality material. Despite recent price drops, silicon is still one of the most expensive components used to make solar cells. This new technology is expected to produce efficiencies between 21% and 23%, in comparison to the 19% of current commercial devices, and further enables price drops in solar modules.
Already worth about $100 billion a year, the solar industry is expected to swell to about $140 billion by 2018, according to estimates published in April by Transparency Market Research.
Installed PV capacity probably surpassed 100 gigawatts worldwide in the March quarter, according to the International Energy Agency. Some forecasts project capacity growth to more than triple this by the end of the decade. Australia ranked ninth, with installed capacity of 2.4 GW at the end of 2012.
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