凝胶网络模板法可控制备NaYF_4:Yb^(3+),Er^(3+)稀土上转换纳米颗粒

Synthesis of NaYF_4:Yb^(3+),Er^(3+) Upconversion Nanoparticles Using Hydrogel Networks as a Template

采用水凝胶空间网孔结构作为纳米级反应容器可控制备了NaYF4:Yb3+,Er3+稀土上转换发光纳米颗粒。通过控制交联剂密度可以改变网络凝胶网孔结构,用不同网孔结构的凝胶模板可以控制合成纳米颗粒。通过XRD、TEM、PL等方法研究了不同凝胶模板对颗粒的尺寸、发光性能的影响。结果表明,利用高分子交联后形成的凝胶网络,可以制得粒径在10 nm左右的NaYF4:Yb3+,Er3+纳米颗粒。随着交联剂浓度的升高,颗粒粒径及荧光强度都有所下降。本研究为稀土上转换发光纳米颗粒的制备提供了工艺简单、绿色环保的新方法。

Hydrogel network structures were used as nano-sized reactors for synthesizing NaYF4：Yb3＋, Er3＋ upconversion nanoparticles with controlled size. By adjusting the crosslinking density, hydrogel networks with different sizes were prepared and used as reactor to control the size of synthesized nanoparticles. The particle size and upconversion luminescence property of the nanoparticles were characterized using XRD, TEM and photoluminescence （PL） spectra. The results show that the size of synthesized NaYF4：Yb3＋, Er3＋ nanoparticles is around 10 nm. The diameter and the luminescence intensity decrease with increase of hydrogel crosslinking density. The increased crosslinking density reduces Ostwald ripening and increases pore pressure, which limit the growth of nanoparticles. The decreased particle size results in broken bonds on the particle surface and particle scatter/ng. Besides, the hydrogel may also quench the fluorescence of the nanoparticles. This research provides a simple and environmentally friendly method for synthesizing uniform upconversion nanopartieles.