Is black phosphorous the new wonder-material?

Two-dimensional crystals such as graphene have extraordinary properties – including two newly discovered ones that we reported this week. But scientists are now discovering that nanosheets of black phosphorous also display remarkable versatility and strength. 

When black phosphorous atoms join together they make a two-dimensional puckered sheet. Last year researchers built a field-effect transistor from this material, suggesting black phosphorous could be used in nanoelectronic devices.

The problem was that it is difficult to make black phosphorous in large quantities. But Damien Hanlon, from Trinity College in Dublin, and his associates, say they have found a way.

In its bulk form, black phosophorous is layered like graphite. One way to separate a single sheet is by using Scotch tape, or a similar material to peel off nano layers. But the method is time consuming.

Hanlon and co found that placing a lump of black phosphorous in a liquid solvent and bombarding it with acoustic waves worked to separate the bulk into nanosheets of only a few layers. 

The team have also been experimenting with uses for the new material in addition to nanoelectronics. They found that adding a film of polyvinyl chloride to black phosphorous nanosheets doubled its strength and increased its tensile toughness by a factor of six.