The nano love triangle
doi:10.1038/nindia.2008.125 Published online 19 February 2008
Making prisms of nanometer magnitude is a daunting task. An Indian research team has done just that — produced gold nanoparticles shaped like tiny prisms that hold promise as raw materials for developing nanosensors and biochips.
Size and shape control is a problem in the utility of nanomaterials. Many researchers have produced nanorods. But, these prisms or nanotriangles (NTs) are new entrants in the field of nanomaterials. To produce NTs, the researchers took conducting glass surfaces coated with indium tin oxide. They used electric field and a stabilizing agent called cetyltrimethylammoniumbromide (CTAB), to let the prisms grow into triangles on glass surfaces.
While analyzing the growth of NTs, the researchers found that within an hour, they showed a uniform and ordered stacking with a width of 375 nanometre (nm) and thickness of 20 nm.
In the absence of electric field and at low temperatures, the nanoparticles shaped up as nanorods. This showed that electric field and temperature play important roles in the growth of NTs.
"This is the first time that such uniform structures have been made and assembled on a surface with well-defined order," says lead researcher Thalappil Pradeep. The researchers say these structures could be important tools for sensitive detection of molecules.
- Sajanlal, P. R. et al. Electric-Field-Assisted Growth of Highly Uniform and Oriented Gold Nanotriangles on Conducting Glass Substrates (p NA). Adv. Mater. doi: 10.1002/adma.200701790 (2008)