NEXT ENERGY from 8 to 10 June at Intersolar Europe 2011

Solar cells are already being installed on roofs and open spaces on a massive scale. Nevertheless, there is still a great need for research because there is still a lot of potential for optimisation in terms of production costs and raw material consumption. One alternative to conventional wafer solar cells that saves both materials and costs is thin-film technology, which the EWE research centre for energy technology NEXT ENERGY in Oldenburg has made the focus of its photovoltaic research. The Institute is focussing on silicon - an element that is ecologically harmless and available in unlimited quantities. Visitors to Intersolar from 8 to 10 June 2011 at the New Munich Trade Fair Centre, where NEXT ENERGY's photovoltaics research department will be exhibiting at stand A2.615, will be able to find out about the specific efforts NEXT ENERGY is making to reduce the production costs of solar cells and increase their efficiency. For the in-depth analysis of loss mechanisms and optimisation potential in silicon thin-film technology, the scientists in the NEXT ENERGY laboratories have the opportunity to test or simulate all factors up to the production of small solar modules:

Solar cell technology

For the production of silicon thin-film solar cells, NEXT ENERGY has a coating system with six process chambers with which silicon layers, transparent conductive oxides (TCOs) and metals can be deposited on a wide variety of substrates. In addition to amorphous silicon pin solar cells ("single-junction"), micromorphous tandem solar cells can also be processed with reproducible efficiencies of more than ten per cent. For this purpose, an amorphous and a microcrystalline pin solar cell are stacked, each absorbing light of a different wavelength.
In the future, the researchers are aiming to extend the usable wavelength range of sunlight even further: "We are working on advancing the development of the triple-junction solar cell with the help of new types of silicon alloys," says Dr Karsten von Maydell, Head of Photovoltaics at NEXT ENERGY. "With the layering of three cells, the utilisation of the solar spectrum can be further extended, which ultimately leads to an increase in the efficiency of the solar cell." The design of the corresponding cell structure has already been derived from extensive simulations. More