We proposed a horseshoe-shaped nanostructure formed by etching a gap on a ring structure.By numerical simulations,it was found that the local field of the structure was significantly enhanced compared with that of the...We proposed a horseshoe-shaped nanostructure formed by etching a gap on a ring structure.By numerical simulations,it was found that the local field of the structure was significantly enhanced compared with that of the traditional ring structure.Furthermore,an additional resonant peak appeared corresponding to the electric field coupling in the gap,and this resonant wavelength was able to be tuned significantly by the particle size,gap size,and gap position.Such properties make the structure promising in biomedical and sensing applications.展开更多
Plasmonics based on localized surface plasmon resonance （LSPR） has found many exciting appli- cations recently. Those applications usually require a good morphological and structural control of metallic nanostructur...Plasmonics based on localized surface plasmon resonance （LSPR） has found many exciting appli- cations recently. Those applications usually require a good morphological and structural control of metallic nanostructures. Oblique angle deposition （OAD） has been demonstrated as a powerful technique for various plasmonic applications due to its advantages in controlling the size, shape, and composition of metallic nanostructures. In this review, we focus on the fabrication of metallic nanostructures by OAD and their applications in plasmonics. After a brief introduction to OAD technique, recent progress of applying OAD in fabricating noble metallic nanostructures for LSPR sensing, surface-enhanced Raman scattering, surface-enhanced infrared absorption, metal-enhanced fluorescence, and metamaterials, and their corresponding properties are reviewed. The future requirements for OAD plasmonics applications are also discussed.展开更多
This article reports the environmentally benign synthesis of gold nanoparticles （GNPs） using methanol extract of Azolla microphylla as the stabilizing and reducing agent. The GNPs were characterized by UV-vis spectr...This article reports the environmentally benign synthesis of gold nanoparticles （GNPs） using methanol extract of Azolla microphylla as the stabilizing and reducing agent. The GNPs were characterized by UV-vis spectrophotometry and FTIR, and the morphological characteristics were analyzed by XRD, FESEM-EDX and HRTEM. The GNPs could be formed in very short time, even in less than 30 min. The nanoparticles measured by UV-spectrophotometer demonstrated a peak at 540 nm corresponding to surface plasmon resonance spectra, and the peaks showed by FTIR suggested the presence of organic biomolecules on the surface of the GNPs. XRD results confirmed the crystalline nature of the GNPs, and FESEM-EDX and HRTEM analyses had been performed in the size ranges of 17-40nm and 1.25-17.5nm respectively. The synthesized GNPs showed excellent antioxidant activity. This study shows the feasibility of using plant sources for the biosynthesis of GNPs.展开更多
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...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.展开更多
基金supported by the National Natural Science Foundation of China under Grants No.61405012 and No.61420106014National Basic Research Program of China(973 Program)under Grant No.2013CBA01702Program for New Century Excellent Talents in University under Grant No.NCET-13-1008
文摘We proposed a horseshoe-shaped nanostructure formed by etching a gap on a ring structure.By numerical simulations,it was found that the local field of the structure was significantly enhanced compared with that of the traditional ring structure.Furthermore,an additional resonant peak appeared corresponding to the electric field coupling in the gap,and this resonant wavelength was able to be tuned significantly by the particle size,gap size,and gap position.Such properties make the structure promising in biomedical and sensing applications.
文摘Plasmonics based on localized surface plasmon resonance （LSPR） has found many exciting appli- cations recently. Those applications usually require a good morphological and structural control of metallic nanostructures. Oblique angle deposition （OAD） has been demonstrated as a powerful technique for various plasmonic applications due to its advantages in controlling the size, shape, and composition of metallic nanostructures. In this review, we focus on the fabrication of metallic nanostructures by OAD and their applications in plasmonics. After a brief introduction to OAD technique, recent progress of applying OAD in fabricating noble metallic nanostructures for LSPR sensing, surface-enhanced Raman scattering, surface-enhanced infrared absorption, metal-enhanced fluorescence, and metamaterials, and their corresponding properties are reviewed. The future requirements for OAD plasmonics applications are also discussed.
文摘This article reports the environmentally benign synthesis of gold nanoparticles （GNPs） using methanol extract of Azolla microphylla as the stabilizing and reducing agent. The GNPs were characterized by UV-vis spectrophotometry and FTIR, and the morphological characteristics were analyzed by XRD, FESEM-EDX and HRTEM. The GNPs could be formed in very short time, even in less than 30 min. The nanoparticles measured by UV-spectrophotometer demonstrated a peak at 540 nm corresponding to surface plasmon resonance spectra, and the peaks showed by FTIR suggested the presence of organic biomolecules on the surface of the GNPs. XRD results confirmed the crystalline nature of the GNPs, and FESEM-EDX and HRTEM analyses had been performed in the size ranges of 17-40nm and 1.25-17.5nm respectively. The synthesized GNPs showed excellent antioxidant activity. This study shows the feasibility of using plant sources for the biosynthesis of GNPs.
基金supported by the National Key Basic Research Program of China (2011CB932802)the National Natural Science Foundation of China (11304054)+1 种基金VAMAS Project (TWA 34 project #5)Public Welfare Research Project (201210284)
文摘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.
