Near/mid‐infrared emission and energy transfer of Er/Tm‐Yb co‐doped β‐NaYF₄ microcrystals

Abstract

The well‐formed high quality β‐NaYF4:Er3+/Tm3+, Yb3+ microcrystals with near/mid‐infrared (NIR/MIR) emission are synthesized by the solvothermal method. Obvious 1.4 μm, 1.8 μm emissions, and 1.5 μm emission are observed in as‐prepared β‐NaYF4:Tm3+, Yb3+ and β‐NaYF4:Er3+, Yb3+ microcrystals, respectively. To obtain MIR emission, the as‐prepared β‐NaYF4:Er3+, Yb3+ microcrystals are heat‐treated at different temperature schedule and atmosphere, it demonstrates there is great effect on the morphology and crystal structure when heat‐treated at different temperature, while little effect under different heat‐treated atmosphere. Subsequently, after heat‐treatment at 575°C in air, owing to the efficient elimination of internal defects and partly surface hydroxyl/citrate groups, an obvious 2.7 μm MIR emission is successfully detected in heat‐treated β‐NaYF4:Er3+, Yb3+ microcrystals for the first time.

Synthesis of ultra‐fine TaB2 nano powders by liquid phase method

“…Field Emission Scanning Electron Microscopy (FE-SEM, JSM-6700F, JEOL, Japan) was used to observe the morphology and the elemental component of the TaB 2 powders, which was equipped with energy dispersive spectroscopy (EDS). In addition, the peaks at 3419 and 1637 are due to -OH and -COOH stretching vibrations, 13 respectively, while the peaks at 2928 and 1406 are due to -C-H stretching vibrations, 14 which indicates the existence of C resource in the TaB 2 precursors. Microstructure and crystal structure of the TaB 2 powders were analyzed by transmission electron microscopy (TEM, JEM-3010, JEOL, Japan) and high-resolution transmission electron microscope.…”

“…The peaks at 1079 and 1201 ascribe to the B-O and B-O-H stretching mode, 12 respectively, which is associate with the presence of boric oxide existed in the TaB 2 precursor system. In addition, the peaks at 3419 and 1637 are due to -OH and -COOH stretching vibrations, 13 respectively, while the peaks at 2928 and 1406 are due to -C-H stretching vibrations, 14 which indicates the existence of C resource in the TaB 2 precursors. Thus, from the FT-IR spectra we can see that the precursor is actually a kind of Ta-B-C-O network system, which indicates the successfully introduction of tantalum and boron atoms in the precursor.…”

Weakening thermal quenching to enhance luminescence of Er3+ doped β‐NaYF4 nanocrystals via acid‐treatment

“…2800‐2950 cm −1 ) and polar groups COOH (ca. 3000‐3500 cm −1 ) . These organic ligands acting as a surface oscillator can significantly quench the luminescence of activated RE ions.…”

“…3000-3500 cm −1 ). 28,29 These organic ligands acting as a surface oscillator can significantly quench the luminescence of activated RE ions. More importantly, the surface organic ligands are one of the main reasons of thermal quenching.…”