Photoluminescence: A very sensitive tool to detect the presence of anatase in rutile phase electrospun TiO2 nanofibers

• Synthesis and characterization of titanium dioxide (TiO2) nanofibers by electrospinning.
• Samples annealed at various temperatures in air for 4 h.
• Heat treatment has an effect on the crystallization process.
• PL is a very sensitive tool to detect the presence of anatase in rutile phase.

This paper reports on the synthesis and the characterization of titanium dioxide (TiO2) nanofibers prepared by electrospinning. The samples were annealed at various temperatures in air for 4 h. The as-spun and annealed TiO2/PVP composite nanofibers were characterized by scanning electron microscopy (SEM), Energy-dispersive X-ray spectroscopy analysis (EDX), X-ray diffraction (XRD), Raman spectroscopy and photoluminescence (PL). The results show that the heat treatment has an effect on the crystallization process. Even if the XRD data shows a complete anatase-to-rutile transition in the TiO2 nanofibers at 900 °C, photoluminescence reveals a small portion of anatase in rutile sample. This observation proved that photoluminescence is a very sensitive tool to detect the presence of anatase in rutile phase TiO2 nanostructures.