Heliatek and glass giant AGC to develop ‘PV windows’

02 Oct 2013

Development agreement to integrate organic solar films in glass.

Heliatek, Dresden, Germany, a manufacturer of solar films, has signed a joint development agreement with AGC Glass Europe, European division of AGC, the world's largest producer of flat glass, which is already active in building integrated photovoltaics (BIPV).

The agreement is focused on researching and developing the integration of glass and solar films, with the aim of developing integrated solutions for the "glass envelope of buildings".

The partners say that this will enable the entire glass façades of buildings, including windows, to become highly efficient, cost-effective solar energy harvesters to reduce a building's carbon footprint combined with a discrete, aesthetically-pleasing, visual appearance.

Heliatek's solar films suit this application because they can be opaque or semi-transparent in a variety of colors. The films are lightweight, ultra-thin and efficient solar converters due to three special features.

1. They harvest solar at peak efficiency for longer daytime periods than traditional solar technologies: from full sun down to one-tenth of full sun, such as on a cloudy day.

2. They can operate efficiently in any orientation - even when not directly facing the sun and only receiving indirect or diffused light.

3. Their photovoltaic performance remains stable up to 80°C.

Market potential

Thibaud Le Séguillon, CEO of Heliatek, commented, “Once developed, this will open up all vertical glass surfaces for PV. They offer a much larger installation area than roof tops that are the focus of today's solar building installations, plus there are no additional installations costs unlike conventional PV panels.”

Marc Van Den Neste, CTO of AGC Glass Europe, said, “This agreement fits in perfectly with our strategy of providing affordable and environment-friendly glass solutions to our customers, the building industry and the community at large. I am confident that this solution will open up new prospects for creativity and energy efficiency to architects and designers.”

Organic technology

The key to Heliatek's technology is the family of small organic molecules – known as oligomers – developed and synthesized at its own lab in Ulm, Germany. Heliatek is the only solar company in the world that uses the deposition of small organic molecules in a low temperature, roll-to-roll vacuum process. Its solar tandem cells are made of nanometer-thin layers of high purity and uniformity. This enables the company to engineer the cell architecture to systematically improve efficiency and lifespan.

The ultra-thin Solar Films are suited to installation between glass panes (in double glazing). Transparency level and color can be tuned to suit the customers' requirements. Measurements by SGS, an accredited and independent testing facility, have confirmed that Heliatek's lab cells offer an efficiency of 7.5% at a light transmission level of 30%. Currently, the company canproduce a transparency level just over 40% in its laboratories in Dresden, Germany.

Heliatek was spun-off in 2006 from the Technical University of Dresden (IAPP) and the University of Ulm. It is a key player in the field of organic photovoltaic and manufactures solar films based on small molecules. Recently, the company set a new world record by achieving a cell efficiency of 12%. It employs 70 staff at its facilities in Dresden and Ulm, Germany. Investors include industrial and financial companies such as BASF, Bosch, RWE, Wellington Partners and eCapital.

About the Author

Matthew Peach is a contributing editor to optics.org.