Japanese chemical manufacturer Kaneka Corporation have created a solar cell with 26.3% photo conversion rate, a 2.7% efficiency increase on the previous record of 25.6%. This may not seem like much but it’s a little more impressive when you note that silicon based solar cells are currently thought to have a ‘theoretical limit’ for energy conversion. This means that no matter how good technology becomes, silcon will never break 29% – i.e. we’re starting to get closer to the ‘end-game’ of our optimisation of silicon solar cells (and need to start looking at alternatives, which is happening).
The technology was funded by a Japanese government program and develops “industrially compaible cells” by implementing layered silicon inside individual cells to minimise band gaps – this approach is called thin-film hetereojunction (HJ) optimisation. It’s not pioneered by Kaneka, but they have managed to optimise the technique by using low resistance electrodes at the rear of the cell and amorphous silicon with an anti-reflective layer on the top.
The Kaneka Corporation, based in Osaka, haven’t begun mass production of the panel yet but we’ll be sure to let you know as soon as they’re available. The researchers, led by Mr Kunta Yoshikawa, published their findings in Nature Energy and noted that “further work is required before the individual cells can be assembled into a commercially available solar panel.”
26.3% isn’t the greatest photo conversion rate we’ve achieved but it is, to date, the highest commercially feasible result. In terms of theoretical results, back in 2014 researchers from UNSW Engineering managed to crack 40% by using a ‘solar tower’ with an optical bandpass filter.
In other news there has been a significant breakthrough – also at UNSW – with regards to high performance perovskite solar cells. Read our article on that to see how we could push solar technology further by using perovskite ‘liquid solar cells’ – one of the top 10 emerging technologies of 2016 (as per World Economic Forum)