Video: Flexible solar cells

Solar technology that’s ahead of the curve (Image: Darren Stevenson and John Rogers)

ELECTRICITY from sunlight: bright hope for the future, or false dawn? Solar power has its share of detractors who’d go for the latter. Photovoltaic cells are too expensive, they say, requiring huge amounts of material and energy to make. And they are inefficient, too, converting at best about 20 per cent of the incoming solar radiation into usable power.

So, the sceptics say, solar cells are only ever likely to be a small, disproportionately expensive part of our future energy mix. In the temperate, oft-cloudy climes of much of Europe and North America, satisfying the population’s electricity needs with photovoltaics alone would mean plastering something like 5 to 15 per cent of the land surface with them.

Such criticisms might be tempered by a new generation of solar cells about to flop off the production line. Slim, bendy and versatile, they consume just a fraction of the materials – and costs – of a traditional photovoltaic device. They could be just the fillip solar power needs, opening the way to a host of new applications: solar-charged cellphones and laptops, say, or slimline generators that sit almost invisibly on a building’s curved surfaces or even its windows.

Photovoltaic cells have traditionally presented renewable-energy enthusiasts with an unenviable choice. If low cost and flexibility are the watchwords, inefficiency is the price to pay: the best flexible solar cells, made from thin films of amorphous silicon or organic polymers, convert barely 10 per cent of solar radiation into power. That makes them unsuitable for all but low-power …