基于PAA模板法制备Ag纳米薄膜复合结构及其光学性质的研究

发布时间：2018-03-23 00:05

  本文选题：多孔阳极氧化铝　切入点：Ag/PAA纳米复合结构　出处：《南京理工大学》2015年硕士论文　论文类型：学位论文

【摘要】：贵金属纳米结构由于其表面等离子体共振效应具有独特的光学性质,如对光的选择性吸收和反射、近场增强等。材料的光学性质不仅与材料本身有关,还与材料的几何结构有关,具有特殊纳米结构的超材料可以通过其几何参数的改变实现对电磁场的调控。将纳米结构的光子共振与金属材料的局域表面等离子体共振相结合可以有效提高材料的光学性质,在太阳能电池、光电转换材料、光催化、分子检测及增强发射等领域具有广泛的应用。本文结合纳米压印技术、阳极氧化法、热蒸发沉积技术和原子层沉积技术制备了Ag纳米薄膜复合结构并研究其光学性质。首先,采用硬纳米压印法和阳极氧化法制备了超薄有序多孔阳极氧化铝(Porous Anodic Alumina, PAA)模板,结合热蒸发沉积技术制备了超薄Ag纳米颗粒/PAA复合结构,并研究了退火时间及退火温度对其光吸收性能的影响。结果表明：在PAA模板上沉积Ag膜后,由于Ag纳米颗粒的等离子体共振作用,Ag/PAA纳米复合结构的吸收率明显提高；当Ag薄膜沉积厚度为30 nm并不进行退火处理时,Ag/PAA纳米复合结构在230～1050 nm的宽光谱范围内一直保持有较高的吸收率,且在525nm处最高吸收率约为90.3%,在1050 nm处的最低吸收率仍为70.3%；其次,采用多步循环氧化-腐蚀扩孔法制备了倒锥型PAA模板,结合热蒸发沉积技术制备了倒锥型Ag/PAA纳米复合结构,并研究了Ag薄膜沉积厚度及退火处理工艺对其光学性质的影响。结果表明：倒锥型PAA的陷光作用、Ag纳米颗粒的等离子体共振作用及颗粒间的耦合效应使得Ag/PAA纳米复合结构的吸收率明显增大,表面增强拉曼散射效果显著增强；倒锥型Ag/PAA纳米复合结构的吸收率随着Ag纳米薄膜沉积厚度的增加而降低；退火处理后,Ag薄膜转变为纳米颗粒,颗粒间存在一定的间隙,倒锥型Ag/PAA纳米复合结构的吸收强度降低,吸收范围变窄,表面增强拉曼散射强度增加。最后,以倒锥型PAA为模板,结合热蒸发沉积技术和原子层沉积技术,制备TiO2/Ag/PAA复合纳米结构,研究了Ag薄膜沉积厚度、Ti02薄膜沉积温度、薄膜沉积层数和退火处理工艺对纳米复合结构光学性质的影响。结果表明：倒锥型TiO2/Ag/PAA纳米复合结构具有较高宽光谱陷光效应；当Ag薄膜沉积厚度为30 nm, TiO2沉积温度为75℃时,所得倒锥型TiO2/Ag/PAA纳米复合结构的吸收效率最高,在475nm处具有96.7%的最高吸收率,在800 nm处的最低吸收率可达达82.5%,在1060 nm和1860 nm处具有两个强吸收峰,吸收率高达80.2%。
[Abstract]:Due to its surface plasmon resonance effect, noble metal nanostructures have unique optical properties, such as selective absorption and reflection of light, near field enhancement, etc. The optical properties of noble metal nanostructures are related not only to the material itself, but also to the material itself. Also related to the geometric structure of the material, Supermaterials with special nanostructures can regulate the electromagnetic field by changing their geometric parameters. Combining the photonic resonance of nanostructures with the local surface plasmon resonance of metallic materials can effectively improve the optical properties of the materials. It has a wide range of applications in solar cells, photovoltaic materials, photocatalysis, molecular detection and enhanced emission. The composite structure and optical properties of Ag nanocrystalline films were prepared by thermal evaporation deposition and atomic layer deposition. Firstly, ultrathin and ordered porous anodic alumina (PAA) templates were prepared by hard nano-imprint and anodic oxidation. Ultrathin Ag nanoparticles / PAA composite structures were prepared by thermal evaporation deposition technique. The effects of annealing time and annealing temperature on the optical absorption properties of Ag films were investigated. The results showed that Ag films were deposited on PAA templates. The absorptivity of Ag / PAA nanocomposite structure was improved obviously because of the plasmon resonance effect of Ag nanoparticles. When the deposition thickness of Ag film is 30 nm and the annealing is not carried out, the Ag / PAA nanocomposite structure has a high absorptivity in the wide spectral range of 230 ~ 1050nm, and the highest absorption rate is about 90.3% at 525nm, and the lowest absorptivity at 1050 nm is still 70.3nm. The inverted cone type PAA template was prepared by multistep cyclic oxidation and corrosion pore expansion method, and the inverted cone type Ag/PAA nanocomposite structure was prepared by means of thermal evaporation deposition. The effects of deposition thickness and annealing process on the optical properties of Ag thin films were studied. The results show that the trapping effect of inverted cone type PAA and the plasmon resonance effect of Ag nanoparticles and the coupling effect between Ag nanoparticles make Ag/PAA nanocrystals. The absorptivity of the composite structure was obviously increased. The effect of surface-enhanced Raman scattering was significantly enhanced, the absorptivity of inverted conical Ag/PAA nanocomposite structure decreased with the increase of deposition thickness of Ag nanocrystalline films, and after annealing, the Ag films changed into nanocrystalline particles, and there was a certain gap between them. The absorption intensity of inverted cone type Ag/PAA nanocomposite structure decreases, the absorption range becomes narrower and the intensity of surface enhanced Raman scattering increases. Finally, the inverted cone type PAA is used as template, combined with thermal evaporation deposition and atomic layer deposition. TiO2/Ag/PAA composite nanostructures were prepared, and the deposition temperature of Ti02 thin films and Ag thin films were studied. The effect of deposition layer number and annealing process on the optical properties of nanocomposite structure was investigated. The results showed that the inverted cone TiO2/Ag/PAA nanocomposite structure had a wider spectral trapping effect, and when the deposition thickness of Ag thin film was 30 nm, the deposition temperature of TiO2 film was 75 鈩，

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