SERS Enhancement Factors Studies of Silver Nanoprism and Spherical Nanoparticle Colloids in The Presence of Bromide Ions
SERS Enhancement Factors Studies of Silver Nanoprism and Spherical Nanoparticle Colloids in The Presence of Bromide Ions
复制标题
DOI：
10.1021/jp809687v
复制
发表时间：
2009-06-04
影响因子：
3.7
通讯作者：
Huang, Cheng-Liang
中科院分区：
文献类型：
--
作者：
Ciou, Shih-Hong;Cao, Yi-Wei;Huang, Cheng-Liang
在KBr存在下，在两种不同的银胶体中观察到了R6 G的表面增强拉曼散射（Sers）。在平均直径为10 +/- 2 nm的球形纳米颗粒中以及在它们的具有钠光照射的光诱导转化产物银纳米棱镜中发现了它，其平均边长为70 +/- 30 nm，厚度为约10 +/- 2 nm。R6 G（4.5 × 10（-9）M）在银纳米棱镜胶体中的Sers强度比在添加KBr（0.05 M）的球形纳米颗粒胶体中强20倍。在相同光谱中比较水（55.5 M）的拉曼信号强度和R6 G（4.5 x 10（-9）M）的Sers强度表明，截短的银纳米棱镜胶体和球形纳米颗粒胶体中的分析增强因子（AEF）分别为约1.6 x 10（5）和8 x 10（3）。在不存在KBr的情况下，监测R6 G的荧光强度与两种胶体中R6 G的浓度的关系，显示纳米棱柱具有比球形纳米颗粒更好的荧光猝灭能力，约为3倍。这意味着光照射不仅使球形纳米颗粒的形貌转变为纳米棱柱，而且改变了其表面性质，使其对染料分子具有更高的亲和力。表面增强因子（SEF）也可以从AEF和在KBr存在下吸附在表面上的染料分子的百分比计算。纳米棱镜和球形纳米颗粒胶体的SEF分别为约3.2 × 10（5）和9 × 10（3）。UV-vis-NIR光谱和TEM图像表明，球形纳米粒子保持分散，而纳米棱柱被溴离子雕刻后，加入KBr。
Surface-enhanced Raman Scattering (SERS) of R6G has been observed in two different silver colloids in the presence of KBr. It was found in spherical nanoparticles with an average diameter of 10 +/- 2 nm and in their photoinduced conversion products with sodium light irradiation, silver nanoprisms, with an average edge length of 70 +/- 30 nm and thickness of about 10 +/- 2 run. The SERS intensity of R6G (4.5 x 10(-9) M) in the silver nanoprism colloid was 20x stronger than in the spherical nanoparticle colloid with the addition of KBr (0.05 M). Comparing the Raman signal intensity of water (55.5 M) and the SERS intensity of R6G (4.5 x 10(-9) M) in the same spectrum showed that the analytical enhancement factors (AEF) in the truncated silver nanoprism colloid and spherical nanoparticle colloid are about 1.6 x 10(5) and 8 x 10(3), respectively. Monitoring the fluorescent intensity of R6G versus the concentration of R6G in two colloids in the absence of KBr displayed that the nanoprisms had better fluorescence quenching ability than the spherical nanoparticles by a factor of around 3. It implied that light irradiation not only converted the morphology of the spherical nanoparticles to nanoprisms, but also changed the surface character to have a higher affinity to the dye molecule. The surface enhancement factors (SEF) can also be calculated from AEF and the percentage of dye molecules adsorbed on the surface in the presence of KBr. The SEF of the nanoprism and spherical nanoparticle colloids are about 3.2 x 10(5) and 9 x 10(3), respectively. The UV-vis-NIR spectra and TEM images show that the spherical nanoparticles remained dispersed, while the nanoprisms were sculptured by the bromide ions after the addition of KBr.