UV emission from self-assembled ZnS nanowires on DNA templates

We report on the self-assembled growth of 8-10 nm ZnS nanoparticles and subsequently nanowires of size similar to 100 nm onto DNA templates driven by the electrostatic interaction between mobile cations (Zn2+) and the negative charges of the phosphate group in DNA backbone. The nanowires show free excitonic ultra-violet (UV) emission at 310 nm along with some defect related emission bands at 345-364 nm. The observed excitonic emission is slightly red-shifted from the optical absorption edge at 300 nm plausibly due to splitting of valence band into hole states. The growth kinetics and relatively lesser internal strain are plausibly responsible for the improved emission spectra of the ZnS nanowires.