Optoelectronic properties of DNA thin films implanted with titania nanoparticle-coated multiwalled carbon nanotubes

Abstract

Rendering the unique features of individual nanoscale constituents into macroscopic thin films remains technologically challenging; the engineering of these constituents habitually compromises their inherent properties. Efficient, environmentally benign, and biodegradable DNA and cetyltrimethyl-ammonium chloride-modified DNA (DNA-CT) thin films (TFs) implanted with titania nanoparticle-coated multiwalled carbon nanotubes (MCNT-TiO2) are prepared by a drop-casting technique. The energy dispersive X-ray spectroscopy studies of DNA and DNA-CT TFs with MCNT-TiO2 identifies various elements (C, O, N, P, Na, and Ti) via quantitative microanalysis. The X-ray photoelectron, Raman, Fourier-transform infrared (FTIR), and UV-visible absorption spectra show changes in the chemical compositions and functional groups associated with binding energies, enhancement of characteristic MCNT-TiO2 Raman bands, and intensity changes and peak shifts of the FTIR and UV-Vis-NIR absorption bands, respectively. The PL spectra indicate an energy transfer in the measured samples, and the quenching of PL indicates a decrease in the recombination efficiency. Lastly, we measure the conductivity, which increased with an increasing concentration of MCNT-TiO2 in the DNA and DNA-CT TFs due to the better connectivity of MCNT-TiO2. By using these materials, the optoelectronic properties of DNA and DNA-CT TFs implanted with MCNT-TiO2 are easily tunable, enabling several engineering and multidisciplinary science applications, such as photonics, electronics, energy harvesting, and sensors.