International Research Fellowship Program: Optimization of Macroporous Metal Films as Substrates for Surfaced Enhanced Raman Spectroscopy

国际研究奖学金计划使美国科学家和工程师能够在国外进行9到24个月的研究。该计划的奖项提供了联合研究的机会，并利用国外独特或互补的设施、专业知识和实验条件。该奖项将支持Mary E.Mulcahy博士与阿根廷里约内格罗巴塞里奥物理研究所的Alejandro Fainstein博士合作，获得为期15个月的研究奖学金。该项目的支持来自国际科学与工程办公室(OISE)的美洲项目。Fainstein博士的实验室是与阿根廷、新西兰和英国的科学家合作的一部分，他们正在探索一种新的方法来制造表面增强拉曼光谱(SERS)活性基片。为了制造这些衬底，在商业上可以买到的亚微米大小的聚苯乙烯乳胶球的存在下，金属被电化学沉积，以产生大孔的金属薄膜。初步实验表明，这些薄膜表现出更好的信号重复性，并且比用于SERS实验的传统的电化学粗糙的金属表面更坚固。为了理解用新底物观察到的增强的基本原理，在腔内的特定区域选择性地沉积分子将是有用的。为了实现这一点，将生产层状金属薄膜，以提供特定金属的空腔，其中散布着一个或多个不同金属的环。烷硫醇的沉积以不同的电位吸附在不同的金属表面，然后可以在空间上进行控制。将检查纳米腔内的活跃区域以及该区域如何随腔的大小变化。在将这项技术实际应用于纳米空间之前，需要验证沉积金属薄层的连续性和均匀性。还将讨论金/银混合纳米腔对纳米腔内产生的等离子体激元的影响。最后，还将探索利用大孔薄膜作为表面增强拉曼散射衬底的检测极限和表面选择规则。

0601826MulcahyThe International Research Fellowship Program enables U.S. scientists and engineers to conduct nine to twenty-four months of research abroad. The program's awards provide opportunities for joint research, and the use of unique or complementary facilities, expertise and experimental conditions abroad.This award will support a fifteen-month research fellowship by Dr. Mary E. Mulcahy to work with Dr. Alejandro Fainstein at Instituto Balserio Physics in Rio Negro, Argentina. Support for this project comes from the Office of International Science and Engineering's (OISE) Americas Program. Dr. Fainstein's laboratory is part of a collaboration with scientists in Argentina, New Zealand, and the UK exploring a new method for making Surface Enhanced Raman Spectroscopy (SERS) active substrates. To make these substrates, metal is electrochemically deposited in the presence of commercially available, submicron-sized polystyrene latex spheres, to produce macroporous, metallic films. Initial experiments with the films show they exhibit better signal reproducibility and are more robust than traditional, electrochemically roughened metal surfaces used in SERS experiments. To understand the fundamental principles which govern the enhancement observed with the new substrates, it would be useful to selectively deposit molecules in specific areas within the cavities. To accomplish this, layered metal films will be produced to give cavities of a particular metal with one or more rings of a different metal interspersed in them. The deposition of alkanethiols, which adsorb onto different metal surfaces at distinct potentials, can be then be spatially controlled. The active area inside the nanocavities and how the area changes with cavity size will be examined. Continuity and uniformity of the thin layers of deposited metal will need to be verified before the technique is actually employed for the nanocavities. The effect that a mixed gold/silver nanocavity will have on the plasmon generated within the nanocavity will also be addressed. Finally, the limit of detection and surface selection rules that can be expected from using the macroporous films as SERS substrates will also be explored.