Polymer-Coated Silicon Nanosheets May Be Graphene Alternative

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene; however, alone nanosheets are less stable. Researchers at the Technical University of Munich (TUM) have produced a novel composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process, bringing about possible future industrial applications like flexible displays and photosensors.

Alina Lyuleeva from the Institute of Nanoelectronics at Technical University of Munich at the atomic force microscope with which the silicon nanosheets were characterized. Courtesy of Uli Benz/TUM.

"Silicon nanosheets are particularly interesting because today's information technology builds on silicon and, unlike with graphene, the basic material does not need to be exchanged," said Tobias Helbich from the WACKER Chair for Macromolecular Chemistry at TUM. "However, the nanosheets themselves are very delicate and quickly disintegrate when exposed to UV light, which has significantly limited their application thus far."

Helbich and his team successfully embedded the silicon nanosheets into a polymer, protecting them from decay. At the same time, the nanosheets are protected against oxidation. This is the first nanocomposite based on silicon nanosheets.

"What makes our nanocomposite special is that it combines the positive properties of both of its components," Helbich said. "The polymer matrix absorbs light in the UV domain, stabilizes the nanosheets and gives the material the properties of the polymer, while at the same time maintaining the remarkable optoelectronic properties of the nanosheets."

Similar to carbon, silicon forms two dimensional networks that are only one atomic layer thick. Like graphene these layers possess extraordinary optoelectrical properties. Embedding them in a polymer, scientists at the Technical University of Munich (TUM) have developed a stable composite material which can be processed with standard polymer technology. Courtesy of Tobias Helbich/TUM.

Its flexibility and durability against external influences also makes the newly developed material amenable to standard polymer technology for industrial processing, putting actual applications within an arm's reach.

The composites are particularly well suited for application in the up and coming field of nanoelectronics.

The TUM research has been published in the Journal of Physics D: Applied Physics (doi.org/10.1088/1361-6463/aa5005).