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. (C) 2010 Elsevier B.V. All rights reserved.