A record breaking thin film solar cell has been developed by scientists at Empa, the Swiss Federal Laboratories for Materials Science and Technology.
A team of researchers led by Ayodhya N. Tiwari at the institute’s Laboratory for Thin Film and Photovoltaics have achieved 20.4 percent energy conversion efficiency for their C.I.G.S. solar cells on flexible polymer foils.
C.I.G.S. solar cells are thin film solar cells that use a semiconducting material known as copper indium gallium selenide. The material is more cost-effective to use and produce than the silicon used as semiconducting material in conventional photovoltaics but current C.I.G.S. cells do not have the efficiency of silicon-based cells.
Improving the efficiency of C.I.G.S. is a task that Mr. Tiwari’s team has been working on since the 1990s. Their new C.I.G.S. cell on flexible polymer substrates broke the previous of 18.7 percent achieved in May 2011 – also from a cell developed by Mr. Tiwari’s team (see related story).
The cell efficiency value was independently certified by the Fraunhofer Institute for Solar Energy Systems in Freiburg, Germany. The new efficiency record for C.I.G.S. on flexible polymers now exceeds the record value of 20.3 percent for C.I.G.S. on glass substrates and equals the highest efficiencies for polycrystalline silicon wafer-based solar cells.
Thin-film solar cells made with C.I.G.S. are attractive for numerous applications – from conventional solar power generation to more innovative projects, such as building-integrated photovoltaics and personal solar devices. They are easier to produce compared to silicon-based P.V. and also use lower costing materials.
“The series of record efficiencies for flexible C.I.G.S. solar cells developed at Empa demonstrates that thin film solar cells can match the excellent performance of polycrystalline silicon cells. Now it is time for the next step, the scale-up of the technology to cover large areas in a cost-efficient roll-to-roll manufacturing process with an industrial partner”, says Gian-Luca Bona the Director of Empa.
Empa will be collaborating with Flison, a start-up company involved in the industrialization of flexible C.I.G.S. solar cells, to commercialize the improved solar cells developed by Mr. Tiwari’s team.
The research was supported by the Swiss National Science Foundation, the Commission for Technology and Innovation, the Swiss Federal Office of Energy and the E.U. Framework Programmes. – EcoSeed Staff