Upconversion emission and cathodoluminescence of Er~(3+)-doped NaYbF_4 nanoparticles for low-temperature thermometry and field emission displays

摘要

The Er~(3+)-doped NaYbF_4 nanoparticles were fabricated by a hydrothermal method.The green and red emissions located at around 525,542 and 657 nm corresponding to the ~2H_(11/2)→~4I_(15/2),~4S_(3/2)→ ~4I_(15/2) and ~4F_(9/2)→ ~4I_(15/2) transitions of Er~(3+) ions,respectively,were observed when pumped at 980 nm light.Furthermore,with the help of the fluorescence intensity ratio technique,the thermo-metric properties of as-prepared products from the thermally coupled ~2H_(11/2) and ~4S_(3/2) levels of Er~(3+) ions were studied by analyzing temperature-dependent upconversion (UC) emission spectra.The maximum sensitivity for the Er~(3+)-doped NaYbF_4 nanoparticles was found to be around 0.0043 K~(-1) with a temperature range of 93-293 K.In addition,the cathodoluminescence (CL) spectrum of the synthesized nanoparticles was nearly the same as the UC emission spectrum and the CL emission intensity did not exhibit saturation with the increase of accelerating voltage and filament current.