With increasing global demand for energy sources beyond gas and oil, there is now more effort than ever before on renewable energy, especially photovoltaics. Almost all of the photovoltaic market today is based on polycrystalline or amorphous silicon - resulting in expensive devices, especially where large areas are needed. Here IDTechEx looks at some of the latest progress in Europe with photovoltaics beyond conventional silicon.
The Fraunhofer Institute for Solar Energy Systems (ISE) is heavily involved in the efforts to commercialize organic photovoltaics. They have recently produced a demonstrator solar module, the size and shape of a door: two meters high and sixty centimeters wide.
The new modules are composed of an organic dye which in combination with nanoparticles converts sunlight into electricity. The modules are semi-transparent which makes them well suited for façade integration. The possibility of producing the modules in different colors, or even to print images or text on them so that it serves as a decorative element open up an entirely new range of possible applications, for example integrating the modules in the glass façade. Used in this way, the new technology not only prohibits direct sunlight from entering the building interior but also generates electricity at the same time.
The wafer-thin electricity-generating film, which lies between two glass panes, is applied using a screen printing technique which promises ease of manufacturing along with the possibilities of a decorative and promotionally effective design and delivery of electricity
The dye solar module is still a prototype. The Fraunhofer researchers have developed it together with industry partners in the ColorSol project funded by the German Federal Ministry of Education and Research BMBF.
One particular challenge posed by the new technology is that the narrow gap between the two glass panes must be hermetically sealed so that no air can get in and destroy the reactive substances inside. The Fraunhofer experts have come up with a special solution to this problem. Instead of using polymeric glue like their competitors, they have decided to work with glass frit. To this end, glass powder is screen-printed onto the panes, and fuses with them at a temperature of around 600 degrees Celcius. Fatigue tests under various weather conditions have shown that the solar cells still function properly even after several thousand hours. The long-term stability as such, however, has yet to be officially certified.
Fraunhofer is not the only institute that's looking into print processing of organic photovoltaics for mass production.
Konarka builds products that convert light to energy. It develops polymer photovoltaic technology that provides a source of renewable power in a variety of form factors for commercial, industrial, government and consumer applications, Konarka has a broad portfolio of patents and technology licenses. The Company's technology is focused on delivering printable, flexible, lightweight and scalable products. Konarka Technologies is headquartered in Lowell, Mass., U.S.A., with European headquarters in Nuremberg, Germany, and research and development facility in Austria. Its PowerPlastic is being jointly developed with Leonhard Kurz GmbH in Germany.
Heliatek, is also looking into organic photovoltaics but with a different approach: They are looking into mass production through vacuum deposition production processes. Based in Dresden and relying on more than 15 years experience in the development and characterization of organic materials and organic devices and obtained key results on several central research areas.
From the above, it is obvious that Germany and the USA still remain at the forefront when it comes to supporting the implementation of technologies that are based on harnessing the power of the sun. As can be seen in table 1, published in late 2007 by the CIBC Corporation, Germany along with the USA and Japan, lead the way, with Spain and the rest of the countries in the Mediterranean expected to rapidly grow, not least because of their ideal location and increased amount of sunlight received per year.
Table 1: Estimated World Market Demand by region
Source: Solarbuzz, Company reports and CIBC World Markets Corp
Other European efforts include, most notably:
G24 Innovations Limited ("G24i"): located in Cardiff, Wales G24i became operational in 2007. Their automated "roll-to-roll" manufacturing process transforms a lightweight roll of metal foil into a 100-pound half-mile of G24i's Dye Sensitized Thin Film in less than three hours. This material is rugged, flexible, lightweight and generates electricity even indoors and in low light conditions.
Other advantages include:
- G24i's advanced cell is silicon and cadmium-free.
- Their thin film is less than 1mm thick.
- Raw materials that are both inexpensive and effectively limitless are incorporated.
- The labor component of their production process is less than 2%.
Carbon Trust: In October 2007, the Carbon Trust unveiled a new research and development programme worth at least £5 million that aims to unlock the potential of organic photovoltaic (PV) technology to deliver solar energy at radically lower costs. The programme will be delivered by the Carbon Trust's preferred partners - the University of Cambridge and The Technology Partnership (TTP) - with the objective of turning solar PV into a cost effective energy source within ten years.
To find out more about these evolving technologies and the bigger picture of the convergence of printing with electronics, attend Printed Electronics Europe in Dresden, Germany on the 8th and 9th of April 2008, the world's premier event on the topic with presentations from photovoltaic companies such as Heliatek and Konarka all the way to insight from end users such as Hasbro and Motorola.
For more information, see www.IDTechEx.com/peEUROPE.
IDTechEx are also staging the World's first event exploring photovoltaic technologies beyond conventional silicon. The event will be held in Denver, Colorado in June, with company visits. For more details see www.IDTechEx.com/pvUSA.
Sources: Fraunhofer Society, G24 Innovations, Konarka, Heliatek. CIBC Corp.