Philip Daizy
Department of Physics, Mar Ivanios College, Thiruvananthapuram 695015, India.
Spectrochim Acta A Mol Biomol Spectrosc. 2008 Nov 1;71(1):80-5. doi: 10.1016/j.saa.2007.11.012. Epub 2007 Nov 22.
Photoluminescent nanoparticles of gold with size 3, 4, 6, and 9 nm are prepared by borohydride/citrate reduction in presence of polyethylene glycol (PEG)/tannic acid. The prepared nanomaterials are characterized by UV-vis spectroscopy and dynamic light scattering (DLS) technique. Intense photoluminescence (PL) is observed in nanoparticles prepared by fast reduction with borohydride in presence of PEG. A red shift of PL emission from 408 to 456 nm is observed for the change of size from 4 to 6 nm. Increase in PL intensity is observed for all the nanoparticles on the addition of KCl. Citrate reduced gold colloid which consists of large particles of size approximately 35 nm with anisotropic shapes showing two plasmon peaks is also prepared. The anisotropy is confirmed by TEM measurement. SERS activity of this colloid is tested using glutamic acid as an adsorbate probe. Assignment of the observed bands is given.
通过在聚乙二醇（PEG）/单宁酸存在下用硼氢化物/柠檬酸盐还原法制备了尺寸为3、4、6和9纳米的金的光致发光纳米颗粒。通过紫外可见光谱和动态光散射（DLS）技术对制备的纳米材料进行了表征。在PEG存在下用硼氢化物快速还原制备的纳米颗粒中观察到强烈的光致发光（PL）。随着尺寸从4纳米变为6纳米，PL发射出现从408纳米到456纳米的红移。添加KCl后，所有纳米颗粒的PL强度均增加。还制备了由尺寸约为35纳米的大颗粒组成、具有各向异性形状且显示两个等离子体峰的柠檬酸盐还原金胶体。通过透射电子显微镜（TEM）测量证实了各向异性。使用谷氨酸作为吸附探针测试了这种胶体的表面增强拉曼散射（SERS）活性。给出了观察到的谱带的归属。
