World's 'most efficient' solar cells developed

A research team at the University of NSW, headed up by Dr Xiaojing Hao of the Australian Centre for Advanced Photovoltaics, has made a major breakthrough in terms of improving solar cell efficiency, according to recent reports.

The team has achieved the highest efficiency rating for CZTS cells (which comprise copper, zinc, tin and sulfur) after three years of work to increase both size and efficiency. According to SBS News, the US-based National Renewable Energy Laboratory (NREL) has confirmed the efficiency rating at 7.6%/cm², but we were unable to easily find this confirmation in a quick check of the NREL website.

Previously developed similar thin-film solar cells have been plagued by cost and toxicity problems. While CdTe (cadmium and telluride) cells are often used in large-scale applications, they are not suitable for residential purposes due to the harmful nature of cadmium. Similarly, demand from LED and LCD technology is putting price pressure on indium (as used in CIGS — copper, indium, gallium and selenium — cells) and making this option less viable. This makes the breakthrough particularly timely, as an alternative to CdTe and CIGS is needed to develop a cost-effective way of harnessing the sun’s power.

Hao says it’s a big jump, but a lot of work is still required to catch up to both in terms of efficiency and cell size. The target is 20% efficiency, which will foster commercial use. If all goes according to plan, the thin, cheap, non-toxic cells could be applied to the entire exterior of a building, rather than just the roof. In markets like Asia, where cities incorporate higher densities of buildings than Australia, this type of application could make it possible to power entire buildings via solar.