Visible photoluminescence from Er3+-doped TiO2 nanofibres by electrospinning

Er3+-doped TiO2 nanofibres were fabricated with electrospinning method followed by annealing in air at 420, 600, 800 and 1000 °C, respectively. The obtained nanofibres are relatively straight and have an average diameter of ∼ 75 nm. X-ray diffraction measurements showed that the crystal structure transforms from anatase to rutile phase with the increase of annealing temperature. Visible photoluminescence peaking at 528.1, 566.6 and 669.3 nm is detected which is ascribed to 2H11/2 → 4I15/2, 4S3/2 → 4I15/2 and 4F9/2 → 4I15/2 transitions of Er3+ ions and the PL intensities increase with the increase of annealing temperature. Meanwhile at high annealing temperatures, near-infrared photoluminescence peaking at 815 nm due to the defect states associated with Ti3+ ions is also found. The strong green photoluminescence of Er3+ ions may have potential applications in one-dimensional luminescent nanodevices.