Scientists and environmentalists have been hopeful of a “solar revolution” in the near future where all electricity will be powered by the sun’s energy. The concept of solar energy has proved to be cost-effective, sustainable and renewable, so substantial development in this field could be very fruitful for such a large-scale initiative.
Researchers at the Karlsruhe Institute of Technology (K.I.T) in Germany have created a new material best suited for photovoltaics, the process of converting solar energy to electricity through conductive material. Professor Christof Wöll, head of K.I.T. Institute of Functional Interfaces, and coauthors of this study believe that the material they have developed will help spur further development of many solar energy applications.
The material constitutes metal-organic framework compounds (MOFs), where metal ions interact to form one- to three-dimensional porous, crystalline structures. According to Wöll, MOFs have been compounds of interest for decades due to their versatility and ability to take on different properties. Wöll and his team chose to create the MOFs for this study based on the porphyrin structure; a rigid, square-planar molecule made up of four rings each containing a nitrogen atom. Porphyrins are highly organized, symmetrical structures often composing molecules in nature such as hemoglobin, chlorophyll and riboflavin.
According to Professor Thomas Heine, a theoretical physicist at Jacobs University of Bremen, Germany and co-author of the study, MOFs also create indirect band gaps. The gaps could help maximize the potential of the material in the future by filling them with molecules that are able to release and take up electric charges.
The frameworks of these molecules are grown in layers on top of each other on a conductive surface to form a homogeneous, thin film termed SURMOFs, a process developed at K.I.T. The films are very thin – only a few hundred nanometers in thickness – making them useful for flexible solar cells and even clothing materials. Wöll says that this is a great new discovery of the applications of MOFs.
“This new application of metal-organic framework compounds is the beginning only. The end of this development line is far from being reached,” Wöll said.
As the demand for sustainable energy increases, we may find possible solutions in this SURMOF material.