Optimising silicon is one route to low-cost solar cells

Sara Ver-Bruggen - 21 Feb 2011

Rather than focus on new exotic materials for achieving cost reductions in solar manufacturing, a new business in California is re-engineering crystal silicon to increase conversion efficiencies of cells.

Solar3D, set up in 2010 with private capital, is looking to transplant light management techniques developed in the fibre-optics industry into solar cell production, to enhance light absorption at the surface and inside the silicon wafer.

Up to 30% of light is reflected off the surface of solar cells, with most commercial crystal silicon cells achieving between 15-18% efficiencies, when the theoretical maximum is around 29%. Solar3D is addressing two principle areas to close this gap.

By the end of 2011 Solar3D will unveil a prototype of a cell with an optical element, based on silicon dioxide, on the surface and re-engineered active structure in the bulk silicon beneath. This will enable the cell to absorb more light and keep photons trapped within structures until they are converted into electrons. Until now the company's engineers have been working on computer simulations of cells, which will inform the development of a prototype cell with boosted efficiencies.

Prototype

According to Jim Nelson, CEO of Solar3D, the company should be able to indicate efficiencies the prototype is capable of in the next few months.

As work on the prototype progresses the company will start discussions with solar cell companies in the US to engage a partner to commercialise its technique, which is compatible with existing silicon solar production processes.

Says Nelson: 'Building-integrated and building-applied photovoltaics - that's where our technology is going to be ideal, as it will bring down the dollar per watt costs of solar cell module manufacturing.'