Scientists have succeeded in constructing the first solar cell made entirely of carbon.Organic solar cells – carbon based – are an objective long pursued by scientists because the element is much cheaper than silicon.”Carbon has the potential to deliver high performance at low cost,” explained Dr. Zhenan Bao, Stanford University.
“By our best information, this is the first demonstration of a functional solar cell that has all its components made of carbon,” he explained.Unlike rigid solar panels made of silicon, the solar cell array carbon rests on a flexible plastic material, where the components are deposited by a printing technique.
This is a major advantage of the entire organic electronics, whose manufacturing process can be done in large scale in continuous form, such as a newspaper printing.
Solar cell carbon
The solar cell carbon is formed by a photoactive layer, which absorbs the sunlight, sandwiched between two electrodes.The active layer is composed of carbon nanotubes and fullerenes – the famous “buckyballs “, carbon molecules shaped like soccer ball.
The electrodes, in turn, in a typical organic solar cell are made of metals – gold, silver or copper – and indium-tin oxide (ITO), the expensive material used in touchscreens.
Marc Ramuz, the team of Dr. Bao managed to replace the silver and ITO for graphene and carbon nanotubes , both with excellent conductive qualities.“Other groups have reported the construction of solar cells entirely of carbon, but they refer only to the active layer, and not to the electrodes,” explained Michael Vosgueritchian, another team member.
It is a historical proof of concept, even though the solar cell go carbon require much research effort before becoming a product ready for use.At the current stage, its main drawback is that it absorbs almost only the wavelengths of light in the near-infrared range, which gives a yield below 1%.
“We clearly have a long way ahead in terms of efficiency,” said Dr. Bao. “But, with better materials and better processing techniques, we hope that this efficiency go up dramatically.”