of research at Fraunhofer ISE are categorized into the following business areas: Energy Efficient Buildings At Fraunhofer ISE, energy-efficient buildings are one of the main areas of research. Teaming up with architects, expert planners and the industry, the researchers at Fraunhofer ISE optimize the performance of existing building and develop the buildings of tomorrow with consideration to the economic aspects, the energy efficiency and the user comfort. Through its involvement in the International Energy Agency (IEA), the Institute contributes in the establishment of the international boundary conditions for the realization of these concepts. In this business area, many disciplines come together: from material research and coating development through to component and system development and finally the required tests. Applied Optics and functional Surfaces Solar energy systems convert solar radiation incident on the earth into thermal, electrical or chemical energy. In order to better transmit, reflect, absorb, filter, redirect or concentrate the incoming radiation, Fraunhofer ISE develops optical components and systems. This business area serves as an interdisciplinary field and serves many areas of solar technology: windows and facades, solar thermal collectors, concentrator systems for photovoltaics and solar power plants as well as photovoltaic module technology. Solar Thermal Systems This business area covers the markets of low and high temperature applications. Solar thermal collectors and collector systems with flat or evacuated tube collectors find numerous applications in the practice. These include process water and solar heating systems, cooling and ventilation systems and sea water desalination systems. Also façade-integrated collectors are implemented. With linear concentrating collectors, operating temperatures from 150 °C to over 400 °C are achieved. Both trough and parabolic collectors are not only used for solar thermal power production in large power plants, but also in simpler and more cost-effective plants for the production of process heat, process steam and driving heat for absorption chillers. Silicon Photovoltaics Especially due to the market introduction programs in Japan and Germany, the role of photovoltaics is gaining more and more on importance. More than 85% of the solar cells produced worldwide are based on crystalline silicon. The price-performance ratio, long-term stability and the cost-reduction potential indicate that this top performer in the terrestrial photovoltaic market will retain its place as market leader longer than just the next decade. Fraunhofer ISE's expertise ranges over the entire value chain of crystalline silicon photovoltaics, starting from material development and crystallization, through to solar cell processing and