Nanotubes could make more robust, cheaper solar cells

Arrays of carbon nanotubes could be a cheaper, more efficient alternative to platinum electrodes in certain solar cells, according to new research.

Scientists at Rice University in Texas and Tsinghua University in Beijing have used new production methods to make components for dye-sensitized solar cells (DSCs), which are potentially cheaper than other cells but commonly use expensive platinum as a catalyst.

Rice’s process of growing nanotubes combined with newly developed sulfide electrolytes made at Tsinghua could lead to more efficient and robust DSCs available at much lower costs than traditional silicon-based solar cells.

The sulfide electrolytes absorb less light than previous designs made from iodine and are less corrosive – a key problem for DSCs’ long-term reliability – but produce a lower power conversion efficiency when tried with platinum electrodes.

Using carbon nanotube electrodes produced a much higher efficiency of 5.25 per cent, although this was still not as high as that from iodine electrolytes and a platinum electrode.

‘The carbon nanotube-to-current collector still has a pretty large contact resistance, and the effects of structural defects in carbon nanotubes on their corresponding performance are not fully understood,’ said Jun Lou, a materials scientist at Rice.

‘But we believe once we optimize everything, we’re going to get decent efficiency and make the whole thing very affordable. The real attraction is that it will be a very low-cost alternative to silicon-based solar cells.’

The project was supported by National High Technology Research and Development Program of China, the Welch Foundation and the Faculty Initiative Fund at Rice.