Nanotechnology offers many chances to benefit the environment and health. It can be applied to save raw materials and energy, develop enhanced solar cells and more efficient rechargeable batteries and replace harmful substances with eco-compatible solutions.

"Nanotechnology is a seminal technology. The UMWELTnanoTECH project association has delivered excellent results. Even the smallest achievements can make a huge contribution to protecting the environment. We must treat the opportunities this future technology offers with responsibility; its eco-compatible use has top priority," said the Bavarian Minister of the Environment, Ulrike Scharf, in Erlangen on 23 November 2016 where the results were presented at the international congress "Next Generation Solar Energy Meets Nanotechnology".

For three years, the Bavarian State Ministry for the Environment and Consumer Protection had financed the association consisting of ten individual projects with around three million euros.

Three Wurzburg projects
Three of the ten projects were located in Wurzburg. Professor Vladimir Dyakonov from the Department of Physics headed the project for environmentally compatible, highly efficient organic solar cells; he was also the spokesman of the "Organic Photovoltaics" section. Anke Kruger, Professor of Chemistry, was in charge of the project on ultra-fast electrical stores based on nano-diamond composites.

Responsibility for the third project rested with Professor Gerhard Sextl, Head of the Fraunhofer Institute for Silicate Research titled "Hybrid capacitors for smart grids and regenerative energy technologies". Sextl, who holds the Chair for Chemical Technology of Material Synthesis at the Julius-Maximilians-Universitat (JMU) Wurzburg, was also the spokesman of the "Energy storage" section.

Below are the three projects from Wurzburg and their results.

Eco-friendly inks for organic solar cells
Organic solar cells have become quite efficient, converting about eleven percent of the solar energy received into electricity.

What is more, they are relatively easy to manufacture using ink-jet printing processes where organic nanoparticles are deposited on non-elastic or flexible carrier materials with the help of solvents. This enables new applications in architecture, for example integrating solar cells in window facades or cladding concave surfaces.

There is, however, a catch to it: So far, most ink-jet printing processes have been based on toxic solvents such as dichlorobenzene. These substances are harmful for humans and the environment and require extensive and costly standards of safety.

The Professors Vladimir Dyakonov and Christoph Brabec (University of Erlangen-Nuremberg) have managed to use nanomaterials to develop ecologically compatible photovoltaic inks based on water or alcohol with equal efficiency. Moreover, the research team has developed new simulation processes: "They allow us to predict which combinations of solvents and materials are suitable for the eco-friendly production of organic solar cells," Dyakonov explains.