摘要
根据Ag+和AuCl-4还原能力的不同,采用分步进料,柠檬酸钠一步还原的方法制备不同摩尔比的AuAg复合纳米粒子。通过紫外可见光吸收光谱、透射电镜等手段对所得复合纳米粒子进行了表征。结果表明,AuAg复合纳米粒子的形状近乎球形,结构密实,单分散性好。金银摩尔比1∶1组成的复合纳米粒子的粒径为48.7nm,最大吸收波长为459nm。采用同步光散射和发射光谱对金、银及复合纳米粒子光散射特性进行了研究。实验显示,随着复合纳米粒子中银摩尔分数的减小,主散射峰逐步红移,其峰值与Ag摩尔分数呈线性关系,λmax=619.5-153.4XAg,相关系数r=-0.9927,散射光强度与Ag摩尔分数也呈线性关系,线性方程为Is=272.1+625.7XAg,相关系数r=0.9957;采用不同的激发波长均能获得多个倍频峰和分频峰,激发波长越短,分频峰的强度越大,说明AuAg复合纳米粒子具有非线性光学特性。复合纳米粒子散射波长、散射强度对组成的这种依赖特性,对于设计特定要求的光学探针具有重要的意义。
A gold-silver alloy nanoparticle was synthesized with trisodium citrate by one-step reduction method, and a series of alloy nanoparticles of different gold and silver mole ratios were obtained. Various techniques, such as ultraviolet-visible spectrophotometry, synchronous light-scattering spectrophotometry, emission spectrophotometry, transmission electron microscopy, were used to characterize the nanoparticles. The diameter of alloy nanoparticle (gold and silver mole ratio 1: 1) was 48.7 mn, it was global and compact. Compared with gold nanoparticle ( 518 nm) and silver nanoparticle (425 nm), it had a unique UV-vis absorption peak at 459 nm. Its maximum light-scattering wavelength was 590 nm. There was a linear relationship between the maximum light-scattering wavelength (lambda(max)) and the molarfraction of silver (X-Ag) in alloy nanoparticles, lambda(max) = 619.5-153. 4 X-Ag, r = 0.9927. The relationship of intensity of scattered light (I-s) and the mole ratio of silver (X-Ag) was also linear, linear equation was I-s = 272.1 + 625.7 X-Ag, and r = 0.9957. In the emission spectrum of alloy nanoparticles, multiple frequency and fractional frequency lights were obtained. It was shown that the gold-silver alloy nanoparticle had a nonlinear optic property.
出处
《分析化学》
SCIE
EI
CAS
CSCD
北大核心
2005年第7期939-942,共4页
Chinese Journal of Analytical Chemistry
基金
国家自然科学基金(No.20375017
20375019)
教育部博士点基金(No.2002005002)资助项目
