"We were able to fabricate thin-film transistors from a material whose major constituent is an inexpensive commodity plastic," team leader Manish Chhowalla told nanotechweb.org. "The technique we used to make the transitors also means that we do not need to develop new processing methodologies for graphene – something that should facilitate the implementation of the material into practical devices."

Graphene-based polymer composites benefit from graphene's excellent thermal, mechanical and electrical properties and they are easy to make. Although graphene itself is a zero bandgap semiconductor, this is the first time that such composites have been shown to be semiconducting.

The researchers made their composite from a solution of graphene and polystyrene in a common solvent, DMF. After spin coating the solution onto a substrate and removing the solvent, a thin film of graphene-polystyrene forms. The material is semiconducting and can be electrostatically doped with electrons, just like graphene itself, and its field-effect mobility rivals those of the best organic thin-film transitors (TFTs), says Chhowalla.

He adds that the material might come in useful for thin-film printed electronics where the active components of devices are processed from solution and deposited on plastic substrates. It can also be deposited uniformly over a large area at relatively low temperatures with high throughput.

The team will now investigate the chemical structure of the material and how it relates to the performance characteristics.

The research was published in Nano Letters.