中文摘要：

采用化学还原法一步合成银纳米立方颗粒，并利用 Stober 法制备了 Ag@SiO2纳米核壳结构，通过改变正硅酸乙酯（TEOS）加入量可调节SiO2壳层厚度（7.5～33.0 nm）。样品吸收光谱表明，Ag@SiO2纳米颗粒的偶极共振吸收峰相对于Ag纳米立方颗粒明显红移，但 SiO2壳层厚度对银纳米立方颗粒的共振吸收峰位影响不大。将 Ag 或 Ag@SiO2纳米颗粒掺入NaYF4：Er^3＋,Yb^3＋上转换纳米发光材料，通过微区荧光光谱研究了单个Ag或Ag@SiO2纳米颗粒对周围NaYF4：Er^3＋,Yb^3＋上转换发光的等离子体增强。测得单个Ag@SiO2纳米颗粒对红光和绿光上转换的增强因子分别为2.7和1.5，而单个Ag纳米颗粒只对绿光有增强。表明该纳米复合材料在太阳能电池及生物检测有着潜在的应用。

英文摘要：

Ag nanocubes （NCs） were synthesized by the chemical reduction method, and Ag@SiO2 nanostructured materials were prepared by the St？ber method. The thickness of SiO2 shell is controlled to be 7.5–33.0nmvia the change of the amount of tetraethyl orthosilicate （TEOS）. The absorption spectra of the samples show that the dipole resonance absorption peak of Ag@SiO2has a red-shift, compared with that of Ag NCs. However, the thickness of SiO2shell has little influence on the position of resonance absorption peak. When the upconversion nanophosphors of NaYF4：Er^3＋,Yb^3＋ are doped in Ag NCs or Ag@SiO2, the surface plasmon enhancement of NaYF4：Er^3＋,Yb^3＋ upconversion fluorescence of single Ag NC or Ag@SiO2 was investigated based on the micro-field fluorescent spectra. The enhancement factors of upconversion with single Ag@SiO2 are 1.5 （green） and 2.7 （red）, and single Ag NC just enhances green upconversion. The experimental results show that this nano-composite material has potential applications in solar cells and biological detection.