Minimizing the effect of near-distance dielectric sensitivity on retrieving average aspect ratio of gold nanorod by optical extinction spectroscopy:in the case of CTAB adsorption  

作　　者：Zhijian Hu Yinglu Ji Shuai Hou Xiaochun Wu 

机构地区：[1]CAS Key Laboratory of Standardization and Measurement for Nanotechnology,National Center for Nanoscience and Technology

出　　处：《Chinese Science Bulletin》2014年第16期1822-1831,共10页

基　　金：supported by the National Key Basic Research Program of China (2011CB932802);the National Natural Science Foundation of China (11304054);VAMAS Project (TWA 34 project #5);Public Welfare Research Project (201210284)

摘　　要：The aspect ratio(AR)is one of the most intriguing parameters of gold nanorods(GNRs),which plays an important role in determining localized surface plasmon(LSPR)properties.Instead of conventional imaging techniques,the optical extinction spectroscopy(OES)method has been developed for allowing fast statistically measuring the average AR under static approximation.In this work,combining with the previous achievements in spectroscopic technique,we further analyze the effects of gold dielectric function and near distance dielectric sensitivity.The former may reflect possible dielectric loss of real Au samples from ideal single crystalline.The latter reflects the cetyltrimethylammonium bromide(CTAB)adsorption on the surface of GNR induces different LSPR shifts below and above critical micelle concentration(CMC).However,their effect on the determination of AR has not been evaluated in OES method.The average AR measurements as a function of absorbance of CTAB-GNRs and LSPR maximum below the CMC were studied.Our results indicate that after considering these factors,the mean ARs obtained from spectroscopic techniques are closer to those obtained from imaging techniques.The aspect ratio （AR） is one of the most intriguing parameters of gold nanorods （GNRs）, which plays an important role in determining localized surface plasmon （LSPR） properties. Instead of conventional imaging techniques, the optical extinction spectroscopy （OES） method has been developed for allowing fast sta-tistically measuring the average AR under static approxi- mation. In this work, combining with the previous achievements in spectroscopic technique, we further ana-lyze the effects of gold dielectric function and near dis-tance dielectric sensitivity. The former may reflect possible dielectric loss of real Au samples from ideal single crys- talline. The latter reflects the cetyltrimethylammonium bromide （CTAB） adsorption on the surface of GNR indu- ces different LSPR shifts below and above critical micelle concentration （CMC）. However, their effect on the deter-mination of AR has not been evaluated in OES method. The average AR measurements as a function of absorbance of CTAB-GNRs and LSPR maximum below the CMC were studied. Our results indicate that after considering these factors, the mean ARs obtained from spectroscopic techniques are closer to those obtained from imaging techniques.

关 键 词：CTAB 消光光谱 吸附作用 平均值 纵横比 纳米棒 灵敏度 近距离 

分 类 号：O657.3[理学—分析化学] TQ131.23[理学—化学]