Solar Nanotubes Make Light Work?
I have been reporting on developments in photovoltaic cells for as long as I can remember and there’s always some new technology or fabrication method that’s going to improve upon the woeful efficiency of today’s silicon based solar cells. I’m still waiting and outside the labs most commercial cells still only manage a fairly miserable 20 – 30 percent efficiency, which basically means that during their lifetime very few solar cells ever recover the enormous amount of energy put into their manufacture, let alone live long enough to generate ‘free’ electricity. I have no doubt that one day the problem will be licked and this might just be the development to do it. It’s a rolled up graphene layer nanotube and it’s the brainchild of a team of researchers at Cornell University. The first problem, though, is that it’s tiny, no larger than a DNA molecule, which means you’ll need an awful lot of them to do anything useful. The good news is that it’s very efficient and when exposed to light the tubular structure creates more electrons, and the cylindrical structure makes it easier for them to flow. I know, we’ve been here before so don’t hold your breath, but one day, it will happen, and maybe, just maybe this is where it started…
Sun Powered Shades
Sadly very few solar powered gadgets are actually green. Hardly any of them will ever recover the energy expended in their manufacture during their working lives, let alone the couple of weeks most of them last, until the novelty has worn off, but that’s another story. No, we’re here to tell you all about a pair of sunglasses fitted with solar panels that can be used to charge an MP3 player or mobile phone. Solar cells are notoriously inefficient and your face would probably burn off long before a useful charge was achieved. I may be wrong, the designers, Hyun-Joong Kim and Kwang-Seok Jeong have used organic dye type cells, which they claim to be both cheap and efficient, but given the relatively small surface areas of the cells, and the need to face directly into the Sun to get the best charge, it all seems a bit dubious.
