Photo-induced formation of semi-conducting Au–Ag aggregated branched nanoalloys on DNA template

A UV-photoirradiation technique has been demonstrated for an innovative, simple, one-step process for the synthesis of semi-conducting Au–Ag aggregated branched nanoalloys on DNA within 3 h. The nanostructures having the diameters range from 4 to 12 nm with length in the micrometer range. During Au–Ag alloy nanostructures synthesis, the DNA acts as both a reducing agent and a non-specific capping agent for the metal nanoparticles. The current–voltage (I–V) under AFM characterization revealed that the nanostructures behave as non-hysteretic semi-conductors at low voltages (<5 V), indicating continuous alloy structure. The deposition of the particles is highly selective on DNA only. These Au–Ag alloy nanostructures may be valuable for the synthesis of other hybrid and composite nanostructures as well as for functional nanodevices, miniature computers, optoelectronics and sensors.

Figure optionsDownload as PowerPoint slideResearch highlights▶ Highly specific chemical structure and the ability to self-assemble complex structures such as cubes, squares and ‘T’ junctions has made nucleic acid or nucleotides an attractive scaffold to make nanostructured materials. ▶ Among the different noble metals studied, gold and silver are of particular interest because of their fascinating properties and potential application in nonlinear optics, electronics, catalysis, biology, and SERS studies. ▶ Our approach is to apply DNA as a template for nanowires synthesis and their application as conducting element for nanodevices. ▶ A one-step, in situ process for the synthesis of an aqueous suspension of Au–Ag alloy nanostructures on DNA template in 3 h of UV-irradiation. ▶ The synthesized alloy nanostructures are found to behave as semi-conducting nature.