Effect of homogeneous coating on K+-doped NaGdF4:Er3+,Yb3+ upconversion materials

• Published in: Journal of materials science. Materials in electronics Vol. 33; no. 2; pp. 596 - 606
• Main Authors: Hu, Haisheng, Jiang, Qun, Li, Yunfei, Liu, Meitang
• Format: Journal Article
• Language: English
• Published: New York Springer US 2022; Springer Nature B.V
• Subjects: Characterization and Evaluation of Materials; Chemistry and Materials Science; Coating effects; Crystal structure; Doping; Erbium; Light emission; Luminous intensity; Materials Science; Nanomaterials; Nanoparticles; Optical and Electronic Materials; Shells; Upconversion; Ytterbium
• ISSN: 0957-4522; 1573-482X
• DOI: 10.1007/s10854-021-07328-w

The K + -doped (Na 1− x K x )GdF 4 :Er 3+ ,Yb 3+ upconversion materials were successfully synthesized by solvothermal method. The doping of K + was testified to have great influences on improving upconversion properties as it directly affects the morphology of the material matrix. In addition, by coating the doped material with a homogeneous shell layer, a newly developed core–shell (Na 0.9 K 0.1 )GdF 4 :Er 3+ ,Yb 3+ @NaGdF 4 nanomaterials were produced. Surprisingly, its light emission intensity was 2 times of that for the uncoated material, although the crystal structure and the emission color of the nanoparticles did not change. The upconversion mechanism has also been studied, and the results show that there is a two-photon mechanism of (Na 1− x K x )GdF 4 :Er 3+ ,Yb 3+ . The work provides a new strategy for enhancing the luminescence density of upconversion materials by coating a homogeneous shell after doping.