Preparation, upconversion/downshifting emissions, temperature sensing, and thermochromic properties of one-dimensional Y2Zr2O7:Er3+/Yb3+tube-in-tube nanostructures via single-nozzle electrospinning

One-dimensional (1D) Y2Zr2O7:Er/Yb 2 Zr 2 O 7 :Er/Yb tube-in-tube nanostructures were prepared via a simple electrospinning technique with a single nozzle. The diameter of the outer tube of the Y2Zr2O7:Er/Yb 2 Zr 2 O 7 :Er/Yb tube-in-tube nanostructures is 190-170 nm, the thickness of the outer wall is 22-20 nm, the diameter of the inner tube is 120-100 nm, and the wall thickness of the inner tube is 17-14 nm. The optical properties of the Y2Zr2O7:Er/Yb 2 Zr 2 O 7 :Er/Yb tube-in-tube nanostructures, including the up-conversion and downshifting luminescence spectra, temperature sensitivity, and thermochromic properties, were studied in detail. Under 980 nm excitation, two weak green emissions at 528 nm and 550 nm, as well as a strong red emission at 650 nm of Er ions, are presented. When excited at 378 nm, the Er ions exhibit strong green emission at 545 nm, two weak red emission peaks at 650 and 680 nm, and near-infrared emission peaks at 1400-1600 nm. With increasing environmental temperature, the luminescence color of the 1D Y2Zr2O7:Er/Yb 2 Zr 2 O 7 :Er/Yb tube-in-tube nanostructures exhibited a transition from "orange -> yellow -> -> yellow -> green" when excited at 980 nm. For the 1D Y2Zr2O7:xEr/yYb 2 Zr 2 O 7 :xEr/yYb tube-in-tube nanostructures (x = 0.01, 0.02, 0.03; y = 0.05, 0.10, 0.15), the maximum values of Sr r are 2.3 % K- 1 under 980 nm excitation and 2.1%K-- 1 under 378 nm excitation within the temperature range of 303-723 K. This work develops integrated multifunctional optical materials and provides an alternative approach for the fabrication of nanoscale smart platforms, advanced displays, and applications in information security.