DST Unit on Nanoscience, Department of Chemistry and Sophisticated Analytical Instrument Facility, Indian Institute of Technology Madras, Chennai 600 036, India.
Langmuir. 2010 Jun 1;26(11):8901-7. doi: 10.1021/la904676u.
A strategy for the preparation of bimetallic mesoflowers (MFs) has been demonstrated by a simple overgrowth reaction. We make hybrid MFs containing Au core and shells of different metals, such as Ag and Pt, by tuning the experimental conditions so as to study region-specific overgrowth. This selective growth is attributed to the specific binding affinity of cetyltrimethylammonium bromide (CTAB) at different crystal planes of Au MF surfaces. We also studied the region-specific, composition dependent surface-enhanced Raman scattering (SERS) activity of single bimetallic MFs to understand their chemical environment. Substrate effects on the SERS activity at single particle level were evaluated by a comparative study of the Raman images of Au, Au/Ag, and Au/Pt MFs. Region-specific SERS activity exhibited by single Au/Ag MF provides an insight into the SERS activity of bimetallic MFs over their monometallic analogues.
一种制备双金属介观花（MFs）的策略是通过简单的超生长反应来实现的。通过调节实验条件，我们制备了含有 Au 核和不同金属（如 Ag 和 Pt）壳的混合 MFs，以研究特定区域的超生长。这种选择性生长归因于十六烷基三甲基溴化铵（CTAB）在 Au MF 表面不同晶面的特定结合亲和力。我们还研究了单双金属 MFs 的区域特异性、组成依赖性表面增强拉曼散射（SERS）活性，以了解它们的化学环境。通过比较 Au、Au/Ag 和 Au/Pt MFs 的拉曼图像，评估了在单粒子水平上基底对 SERS 活性的影响。单 Au/Ag MF 表现出的区域特异性 SERS 活性为理解双金属 MFs 相对于其单金属类似物的 SERS 活性提供了线索。
