Angewandte Chemie International Edition ,
Bundles of cysteine–lead nanowires spread into highly oriented structures
Contact: Xiu-Ping Yan, Nankai University, Tianjin (China)
Registered journalists may download the original article here:
Facile Shape-Controlled Synthesis of Well-Aligned Nanowire Architectures in Binary Aqueous Solution
Under an electron microscope they look like dandelions. In the journal
Angewandte Chemie, Xiao-Fang Shen and Xiu-Ping Yan explain their
nanoscopic bouquets: They consist of spread-out bundles of nanowires
made of lead and the amino acid l-cysteine. The
Chinese researchers have discovered a new, cost-effective method by
which ordered nanostructures can be produced on a large scale, at room
temperature, and under atmospheric pressure.
The properties of nanomaterials are not determined exclusively by their
chemical composition; other characteristics such as structure and
morphology, as well as the form, size, and spatial distribution of the
individual particles, also play a role. It is equally important for the
construction of future nanocomponents that nanomaterials can be produced
with controlled “architecture”. For example, one-dimensional
nanoobjects, known as nanowires, are needed for the (opto)electronics of
the future and for the construction of superordinate structures.
Thanks to their specific structures and fascinating penchant for
self-assembly, biomaterials make particularly interesting “molds” for
the production of defined inorganic nanostructures. In particular, the
amino acid cysteine easily forms coordination compounds with inorganic
cations and metals.
The research team at Nankai University started with an aqueous solution
of cysteine and lead acetate. At room temperature and under certain
conditions, spindly bundles of nanowires form. These bundles spread out
to form dandelion-like structures with a highly oriented morphology.
When heated under hydrothermal conditions, these structures decompose.
Depending on the reaction conditions, hierarchical lead sulfide
microstructures are formed with various attractive shapes, including
spherical, needle-like, and different flower-like structures. Lead
sulfide is an important semiconductor.
“Our new process enables the simple, controlled synthesis of nanowires
and three-dimensional lead sulfide microstructures,” summarizes Yan. “In
addition, we expect to gain new insights into the fundamental processes
involved in mineralization, the transformation of bioorganic nano- and
microstructures into inorganic structures. This process also occurs in
living organisms, in which it plays an important role.”