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采用化学还原法一步合成银纳米立方颗粒,并利用St?ber法制备了Ag@Si O_2纳米核壳结构,通过改变正硅酸乙酯(TEOS)加入量可调节Si O_2壳层厚度(7.5~33.0 nm)。样品吸收光谱表明,Ag@Si O_2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Si O_2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@Si O_2纳米颗粒掺入Na YF_4: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@Si O_2纳米颗粒对周围Na YF_4:Er~(3+),Yb~(3+)上转换发光的等离子体增强。测得单个Ag@Si O_2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。
The Ag @ Si O_2 nanoshells were prepared by the chemical reduction method and Ag @ Si O_2 nanoshells were prepared by St? Ber method. The thickness of Si @ O_2 shell can be adjusted by changing the amount of TEOS (7.5 ~ 33.0 nm). The absorption spectra of the samples show that the dipole resonance absorption peak of Ag @ Si O_2 nanoparticles is obviously red-shifted relative to that of Ag nano-cubic particles, but the thickness of Si O_2 shell has little effect on the resonance absorption peak of silver nano-cubic particles. The Ag or Ag @ Si O_2 nanoparticles were doped into NaYF_4: Er ~ (3 +) and Yb ~ (3+) upconverting nano luminescent materials. The effect of single Ag or Ag @ Si O_2 nanoparticle pairs Plasma enhanced by up-conversion luminescence around Na YF_4: Er ~ (3 +), Yb ~ (3+). The enhancement factors of single Ag @ Si O_2 nanoparticles on the red and green upconversion were measured to be 2.7 and 1.5, respectively, while the single Ag nanoparticles only enhanced the green light. It shows that the nanocomposites have potential applications in solar cells and biological detection.