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Forschungszentrum Jülich - Annual Report 2011

67 UsingKnowledge Research for Practical Applications Industry and public research institutions exploit Jülich know-how in the fields of image processing of medical data, biotechnology and photovoltaics – from acquiring software licences to training for their members of staff and in collaborative projects. In 2011, the prestigious “Deutsche Grün- derpreis” for new businesses in the cat- egory of “up-and-coming businesses” went to 4JET Technologies – a company with more than 50 employees which specializes in machining and cleaning surfaces with laser beams. “An excellent instinct for growing markets” and “a pio- neering role in competition” were the remarks of the jury about the company, which is based in Alsdorf and has worked with the Jülich Institute of En- ergy and Climate Research (IEK) since 2009. “Our shared interest is the use of laser technology in producing thin-film solar cells and ultimately making photo- voltaics cheaper and more efficient,” says Dr. Stefan Haas of IEK. The production of solar cells made of thin layers requires less energy and ma- Use of lasers in photovoltaics terial than their conventional counter- parts. They comprise a glass base, upon which a layer of conductive oxide (trans- parent conducting oxide, TCO) is first applied as a transparent electrode. A stack of amorphous or microcrystalline silicon layers are then applied on top of this. In these layers, the atomic compo- nents are either not arranged in crystal lattices at all or they are only arranged in crystal lattices in small areas. A layer of silver is applied as the final layer and functions as an electrode on the back. The different layers are applied using special equipment, which has to be cleaned with chemicals in a costly and time-consuming process. IEK and 4JET have therefore developed an alternative process which uses lasers for this clean- ing. In 2011, the collaboration reached a new dimension: the Ministry of Econom- ics of North Rhine-Westphalia and the European Union granted the “LaText” project focusing on laser processes for texturing front contacts for silicon thin- film solar cells funding for a period of three years. “We want to use a laser to design the surface of the TCO layer in such a way that the light in the underly- ing silicon layers is reflected as fre- quently and strongly as possible. This increases the light yield and the effi- ciency of the cell,” explains Haas. Light trapping is the term used by experts in the field and the aim is to use surface textures to achieve light trapping in the range of thousandths of a millimetre. “To date, it has proved impossible to create such textures on large areas and selectively,” says Haas. Dr. Stefan Bergfeld, MBA of 4JET Technologies and Chief Technical Offic- er, is convinced of the benefits of the cooperation with scientists at Jülich for the company. “The scientists at IEK work at an extremely high level and they know what will be required in ten years’ time.” One team: Dr. Stefan Haas (left) and Tobias Knüttel (centre) from Forschungszentrum Jülich with Dr. Stefan Bergfeld from 4JET Technologies.