纳米Ag粒子与SiO_2复合薄膜的热稳定性

Thermal stability of silver nanoparticles and SiO_2 composite films

采用溶胶-凝胶法利用水解反应制备了纳米Ag粒子与SiO2复合的nano-Ag∶SiO2薄膜,通过对Ag纳米粒子局域表面等离子体共振(SPR)吸收光谱的观测,探讨了薄膜的热稳定性。利用TG-DSC、XRD、TEM、SEM和EDS等对nano-Ag∶SiO2的物性进行了研究。结果表明:nano-Ag∶SiO2薄膜在不同温度(200～900℃)下热处理,随着热处理温度的升高,薄膜中Ag纳米粒子的SPR特征吸收峰从无到有并逐渐增强,500℃、600℃峰值强度最强,然后逐渐减弱至消失;薄膜500℃热处理的热稳定性良好,复合纳米材料中SiO2为非晶态;当热处理温度升至700℃时,随退火时间的增加出现Ag纳米粒子扩散挥发的现象,并且SiO2由非晶态逐渐转变为晶态。

Nano-Ag-SiO2 composite films with Ag nanoparticles embedded in SiO2 were prepared by sol-gel method via hydrolyze reactions.The thermal stabilization of nano-Ag-SiO2 film was investigated by the absorbance spectrum of localized surface plasmon resonance（SPR） of Ag nanoparticles.The nano-Ag-SiO2 film was further characterized by thermogravimety-differential scanning calorimetry（TG-DSC）,X-ray diffraction（XRD）,transmission electron microscopy（TEM）,scanning electron microscopy（SEM） and energy dispersire spectrometer（EDS）.The results show that the SPR peaks of Ag nanoparticles in the films appear and strengthen after annealeding,then weaken and finally disappear when the annealing temperature increases from 200 to 900 ℃,with the maximum absorbance at the annealing temperature of 500 and 600 ℃.The film annealed at 500 ℃ has a good thermal stability,wherein SiO2 in the nanocomposites is amorphous.Ag nanoparticles get diffusing and volatilizing with increasing the temperature to 700 ℃ and the annealing time increases,at the same time,SiO2 particles transform into crystalloid from noncrystal.