My watch list


First Solar Cell Made of Highly Ordered Molecular Frameworks

New Material Based on Metal-organic Frameworks (MOFs) Is Suited for Photovoltaics


Organic solar cells made of metal-organic frameworks are highly efficient in produc-ing charge carriers.

22-Jun-2015: Researchers at KIT have developed a material suited for photo-voltaics. For the first time, a functioning organic solar cell con-sisting of a single component has been produced on the basis of metal-organic framework compounds (MOFs). The material is highly elastic and might also be used for the flexible coating of clothes and deformable components. This development success is presented on the front page of the journal Angewandte Chemie International Edition.

“We have opened the door to a new room,” says Professor Christof Wöll, Director of KIT Institute of Functional Interfaces (IFG). “This new application of metal-organic framework compounds is the be-ginning only. The end of this development line is far from being reached,” the physicist emphasizes.

Metal-organic frameworks, briefly called MOFs, consist of two basic elements, metal node points and organic molecules, which are assembled to form microporous, crystalline materials. For about a decade, MOFs have been attracting considerable interest of re-searchers, because their functionality can be adjusted by varying the components. “A number of properties of the material can be changed,” Wöll explains. So far, more than 20,000 different MOF types have been developed and used mostly for the storage or separation of gases.

The team of scientists under the direction of KIT has now produced MOFs based on porphyrines. These porphyrine-based MOFs have highly interesting photophysical properties: Apart from a high effi-ciency in producing charge carriers, a high mobility of the latter is observed. Computations made by the group of Professor Thomas Heine from Jacobs University Bremen, which is also involved in the project, suggest that the excellent properties of the solar cell result from an additional mechanism – the formation of indirect band gaps – that plays an important role in photovoltaics. Nature uses porphy-rines as universal molecules e.g. in hemoglobin and chlorophyll, where these organic dyes convert light into chemical energy. A met-al-organic solar cell produced on the basis of this novel porphyrine-MOF is now presented by the researchers in the journal Angewandte Chemie (Applied Chemistry). The contribution is entitled “Photoinduzierte Erzeugung von Ladungsträgern in epitaktischen MOF-Dünnschichten: hohe Leistung aufgrund einer indirekten elekt-ronischen Bandlücke?“ (photo-induced generation of charge carriers in epitactic MOF-thin layers: high efficiency resulting from an indirect electronic band gap?).

“The clou is that we just need a single organic molecule in the solar cell,” Wöll says. The researchers expect that the photovoltaic capac-ity of the material may be increased considerably in the future by filling the pores in the crystalline lattice structure with molecules that can release and take up electric charges.

By means of a process developed at KIT, the crystalline frameworks grow in layers on a transparent, conductive carrier surface and form a homogeneous thin film, so-called SURMOFs. “The SURMOF process is suited in principle for a continuous manufacturing process and also allows for the coating of larger plastic carrier surfaces,” Wöll says. Thanks to their mechanical properties, MOF thin films of a few hundred nanometers in thickness can be used for flexible solar cells or for the coating of clothing material or deformable components. While the demand for technical systems converting sunlight into electricity is increasing, organic materials represent a highly interesting alternative to silicon that has to be processed at high costs before it can be used for the photoactive layer of a solar cell.

Original publication:
Jinxuan Liu et al.; Photoinduzierte Erzeugung von Ladungsträgern in epitaktischen MOF-Dünnschichten: hohe Leistung aufgrund einer indirekten elektronischen Bandlücke?, Angewandte Chemie, Ausgabe 25/2015.

Facts, background information, dossiers

More about KIT

  • News

    Producing Graphene from Carbon Dioxide

    The general public knows the chemical compound of carbon dioxide as a greenhouse gas in the atmosphere and because of its global-warming effect. However, carbon dioxide can also be a useful raw material for chemical reactions. A working group at Karlsruhe Institute of Technology (KIT) has n ... more

    Scientists observe nanowires as they grow

    At DESY's X-ray source PETRA III, scientists have followed the growth of tiny wires of gallium arsenide live. Their observations reveal exact details of the growth process responsible for the evolving shape and crystal structure of the crystalline nanowires. The findings also provide new ap ... more

    3-D-printing of glass now possible

    Glass is one of mankind's oldest materials. It was used as far back as in ancient Egypt and ancient Rome and has found a place now also in manufacturing technology of the 21st century. An interdisciplinary team at the KIT led by mechanical engineer Dr. Bastian E. Rapp developed a process us ... more

  • q&more articles

    Analytical quantitation of gluten in foods

    According to legislation, foods bearing a gluten-free label must not contain more than 20 mg of gluten per kilogram, which is crucial to ensure food safety for celiac disease patients. Gluten is detected by immunological, genomic, chromatographic and/or mass spectrometric methods, but the c ... more

    Assessing the lung toxicity of air pollutants

    The current debates on driving bans in European cities show not only how important air quality is to the public but also reveal the lack of available methods to directly assess the adverse effects of air pollutants on human health. more

  • Authors

    Prof. Dr. Katharina Scherf

    Katharina Scherf, born in 1985, leads the Department of Bioactive and Functional Food Chemistry at the Institute for Applied Biosciences, Karlsruhe Institute of Technology (KIT). Having studied food chemistry at the Technical University of Munich (TUM) she obtained her PhD degree and qualif ... more

    Majlinda Xhaferaj

    Majlinda Xhaferaj, born in 1992, completed her food chemistry studies in 2018 at the Karlsruhe Institute of Technology (KIT). Since 2019 she has been a PhD student under the supervision of Professor Dr. Katharina Scherf in the Department of Bioactive and Functional Food Chemistry. Her resea ... more

    Dipl. Ing. Sonja Mülhopt

    Sonja Mülhopt earned her diploma in mechanical engineering at the Berufsakademie Mannheim (now DHBW) in 2000, completing her concomitant training at the Karlsruhe Research Center, now the Karlsruhe Institute of Technology (KIT). In 2014 she received the Master of Science in Chemical Enginee ... more

q&more – the networking platform for quality excellence in lab and process

The q&more concept is to increase the visibility of recent research and innovative solutions, and support the exchange of knowledge. In the broad spectrum of subjects covered, the focus is on achieving maximum quality in highly innovative sectors. As a modern knowledge platform, q&more offers market participants one-of-a-kind networking opportunities. Cutting-edge research is presented by authors of international repute. Attractively presented in a high-quality context, and published in German and English, the original articles introduce new concepts and highlight unconventional solution strategies.

> more about q&more

q&more is supported by:


Your browser is not current. Microsoft Internet Explorer 6.0 does not support some functions on Chemie.DE