The Effect of DNA Adsorption on Optical Transitions in Single Walled Carbon Nanotubes

Photoluminescence (PL) from a single-walled carbon nanotube (SWNT) is sensitively influenced by molecular adsorption on the surface of SWNT, and is thus useful for analysis of molecular adsorption. We investigated PL spectra from DNA and SWNT hybrids and successfully obtained PL spectra from isolated DNA–SWNTs on a substrate under the dry condition. PL peak energies from single-stranded DNA–SWNT hybrids depended on the DNA base type, namely thymine, adenine, cytosine, and guanine. The base type dependence was attributed to the polarizability of the electronic charge distribution between the DNA base molecules and SWNT, which correlates to the adsorption energy of the DNA bases on the SWNT surface. The present results demonstrate that PL provides information on the DNA and SWNT binding