Electrospinning preparation and high near-infrared temperature sensing performance of one-dimensional Y2Ti2O7:Cr3+/Yb3+ nano wire-embedded-tube structures with low Cr3+ concentrations

One-dimensional Y2Ti2O7:Cr3+/Yb3+ nano wire-embedded-tube structures composed of an outer nanotube with an outside diameter of 180-200 nm and a wall thickness of 30-36 nm and embedded wire with a diameter of 32-36 nm were fabricated via a simple single-nozzle electrospinning method at an air humidity of 45%. The Cr3+ content in the one-dimensional Y2Ti2O7:Cr3+/Yb3+ nanostructures is very low and accounts for approximately 0.5% of the total moles of Yb3+, Y3+, and Cr3+ ions. The energy transfer mechanism from Cr3+ to Yb3+ is systematically studied. The near-infrared luminescent properties of the one-dimensional Y2Ti2O7:Cr3+/Yb3+ nano wire-embedded-tube structures, especially the temperature sensing performance, were investigated. The one-dimensional Y2Ti2O7:Cr3+/Yb3+ nano wire-embedded-tube structures have emissions of 650-1100 nm and excellent temperature sensing properties. The maximum absolute sensitivity (S-a) and high relative sensitivity (S-r) values are 6.01-8.73%K-1 and 3.93-4.71%K-1, respectively, which are much higher than those of the previous Cr3+ and Cr3+/RE3+ co-doped near-infrared phosphors and other up-conversion phosphors doped by RE3+ ions.