December 7, 2015

New approaches for hybrid solar cells

Filled with suitable organic polymers the highly porous germanium nanofilm becomes
a hybrid solar cell – Photo: Andreas Battenberg

Nanostructured germanium for portable photovoltaics and battery electrodes

(December 7, 2015)  Using a new procedure researchers at the Technical University of Munich (TUM) and the Ludwig Maximillians University of Munich (LMU) can now produce extremely thin and robust, yet highly porous semiconductor layers. A very promising material – for small, light-weight, flexible solar cells, for example, or electrodes improving the performance of rechargeable batteries.

The coating on the wafer that Professor Thomas Fässler, chair of Inorganic Chemistry with a Focus on Novel Materials at TU Munich, holds in his hands glitters like an opal. And it has amazing properties: It is hard as a crystal, exceptionally thin and – since it is highly porous – light as a feather.

Electronmicroscopical image of the germanium-structure after removal
of the polymer templates – Image: Katia Rodewald / TUM

By integrating suitable organic polymers into the pores of the material, the scientists can custom tailor the electrical properties of the ensuing hybrid material. The design not only saves space, it also creates large interface surfaces that improve

“You can imagine our raw material as a porous scaffold with a structure akin to a honeycomb. The walls comprise inorganic, semiconducting germanium, which can produce and store electric charges. Since the honeycomb walls are extremely thin, charges can flow along short paths,” explains Fässler.

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