Quantum dots for cheaper solar panels

Rice University scientists have unveiled a breakthrough method for producing quantum dots, a discovery that could lead to better and cheaper solar energy panels.

Michael Wong and scientists at Rice's Centre for Biological and Environmental Nanotechnology used a chemical method for making four-legged cadmium selenide quantum dots, which previous research has shown to be particularly effective at converting sunlight into electrical energy.

Quantum dots are ‘megamolecules’ of semiconducting materials that are smaller than living cells. They interact with light in unique ways, to give off different-coloured light or to create electrons and holes, due partly to their tiny size, partly to their shape and partly to the material they're made of.

One way towards cheaper solar cells is to make them out of quantum dots. Prior research has shown that four-legged quantum dots, which are called tetrapods, are many times more efficient at converting sunlight into electricity than regular quantum dots. But, Wong said the problem is that there is still no good way of producing tetrapods. Current methods lead to a lot of particles with uneven-length arms, crooked arms, and even missing arms. Even in the best recipe, 30 per cent of the prepared particles are not tetrapods, he said.