Molecular "stencils" open up new possibilities for solar energy

Scientists at the US Department of Energy's Argonne National Laboratory have begun to use molecular ''stencils'' to pave the way to new materials that could potentially find their way into future generations of solar cells, catalysts and photonic crystals.

Researchers at Argonne's Center for Nanoscale Materials and Energy Systems Division have developed a technique known as sequential infiltration synthesis (SIS), which relies on the creation of self-assembled nanoscale chemical domains into which other materials can be grown.

This film of block copolymers shows the material's characteristic tendency to separate into distinct regions

In this technique, a film composed of large molecules called block copolymers acts as a template for the creation of a highly-tunable patterned material.

This new method represents an extension of atomic layer deposition (ALD), a popular technique for materials synthesis that is routinely used by Argonne scientists. Instead of just layering two-dimensional films of different nanomaterials on top of one another, however, SIS allows scientists to construct materials that have much more complex geometries.

''This new technique allows us to create materials that just weren't possible with ALD or block copolymers alone,'' said Seth Darling, an Argonne nanoscientist who helped to develop SIS in collaboration with Argonne chemist Jeff Elam. ''Having the ability to control the geometry of the material we're making as well as its chemical composition opens the door to a whole universe of new materials.''

The Center for Nanoscale Materials is supported by the US Department of Energy's Office of Basic Energy Sciences (BES). This work was supported in part by the Argonne-Northwestern Solar Energy Research Center, an Energy Frontier Research Center also supported by BES.