其消光性能
(中南大學(xué) 資源加工與生物工程學(xué)院，長沙 410083)
摘 要: 利用預(yù)處理−化學(xué)鍍法在氧化硅納米線表面包覆銀層，制備出具有一維核−殼結(jié)構(gòu)的氧化硅/銀納米復(fù)合材料。結(jié)果表明：當(dāng)Ag(NH3)2+濃度為0.05~0.25 mol/L時(shí)，可在氧化硅納米線表面形成銀包覆層，隨著銀氨離子濃度的增加，其厚度從數(shù)十納米增加到上百納米；銀殼層由大小不一、純度很高、面心立方結(jié)構(gòu)的銀納米粒子緊密堆積而成；一維氧化硅/銀核−殼納米復(fù)合材料的實(shí)測(cè)值紫外−可見吸收光譜和采用離散偶極近似理論模擬計(jì)算的理論光譜很接近；可見光區(qū)的吸收峰和近紅外區(qū)的吸收峰分別來源于核−殼納米復(fù)合材料橫向和縱向偶極表面等離子體共振銀層厚度的增加使近紅外區(qū)的吸收峰發(fā)生明顯藍(lán)移。
關(guān)鍵字: 氧化硅/銀；一維核−殼納米結(jié)構(gòu)；化學(xué)鍍；消光性能；離散偶極近似
（School of Resources Processing and Bioengineering, Central South University, Changsha 410083, China）
Abstract: By pretreatment electroless silver deposition, one-dimensional silica/silver nanocomposite with core-shell structure was fabricated by coating silica nanowires with a layer of silver. The results show that a silver layer can be formed on the surface of silica nanowires at the concentration of Ag(NH3)2+ from 0.05 to 0.25 mol/L, and the thickness of silver layer can be increased from several tens to more than one hundred nanometers with increasing concentration of Ag(NH3)2+. The silver layer consists of pure silver nanoparticles with face-centered cubic structure and different size. The UV-Vis spectra of one-dimensional silica/silver nanocomposite accords with the theoretic spectra by discrete dipole approximation simulation. The absorption bands locating at the visible and near infrared region come from the transverse and longitudinal modes of surface plasma resonance of nanocomposite, respectively. The increase of silver thickness results in the obvious blue-shift of absorption band at near infrared region.
Key words: silica/silver; one-dimensional core-shell nanostructure; electroless deposition; extinction property; discrete dipole approximation
