Electrospinning preparation and upconversion luminescence of Y2Ti2O7:Tm/Yb nanofibers

Nanoscale Y2Ti2O7:Tm3+/Yb3+ fibers were fabricated through electrospinning followed by calcining at high temperatures. The resulting Y2Ti2O7:Tm3+/Yb3+ fibers were characterized by XRD, SEM, TEM, EDX, and ICP-OES. The average diameter of the Y2Ti2O7:Yb/Tm nanofibers is about  80 nm and they are hundreds of microns long. Their upconversion (UC) intensity was found to increase with increasing Yb3+ concentration within the working current range of 1.50–2.50 A under 980-nm laser irradiation. The mechanism of energy transfer between Yb3+ to Tm3+ ions in the Y2Ti2O7:Yb/Tm nanofibers was also elucidated The three-photon processes and the two-photon processes were confirmed to be involved in blue emissions and red and near-infrared emission by analyzing the UC-intensity dependence on the operating current of the 980-nm exciting laser.