Photoluminescence properties of TiO2 nanofibers

Multi-walled carbon nanotube (MWCNT)TiO2 nanofiber (NF) composites forming a layered nanostructure (MWCNTs/TiO2 NFs/Ti) were prepared by impregnation at low temperature. Room temperature photoluminescence (PL) of these nanostructures shows a broad intense band in the visible light range (similar to 450600 nm). The origin of the PL emission which, mainly, resulted from surface oxygen vacancies and other defects was investigated. We studied the effect ofMWCNT deposition on the PL of TiO2 NFs where theMWCNTs can act as an electron reservoir of electrons emitted from TiO2 nanofibers when irradiated with UV light. The combination of MWCNTs and TiO2 results in quenching of TiO2 luminescence in the visible range. In addition, the prepared surface of MWCNTs-TiO2 was irradiated with Ti+ ions using irradiation energy of 140 keVand doses of 10(13) ions/cm(2). Also, this treatment induced the PL intensity quenching due to the generation of non-radiative additional levels inside the band gap.