Properties of hydrothermally processed multi-walled titania nanotubes

► Sub-micron sized long TiO2 nanotubes (TNTs) were grown via a hydrothermal route. ► Optical properties of multiwall TNTs with 5-7 walls and a wall spacing of 0.36 nm were explored. ► The overall PL emission response of TNTs is relatively weak as compared to TNPs. ► Electron-phonon coupling was found to be stronger in TNPs than TNTs.