半导体纳米结构的表面增强拉曼散射效应研究及传感应用探索

The extremely high sensitivity and selectivity of surface enhanced Raman scattering (SERS) have attracted increasing attention in the field of sensor. However, the group 11 metals (Au, Ag, Cu) based SERS resulted from electromagnetic enhancement has not been developed as a practical technology in sensing field, due to their poor biocompatibility, high cost and difficulty in fabricating. Based on our previous theoretical and experimental studies, semiconductor-based SERS will be demonstrated by utilizing the photo-induced charge transfer (PICT) between the analytes and the nanostructured Si, Ge, and ZnO substrates under certain conditions, by which the limitation of group 11 metals (Au, Ag, Cu) based SERS in practical application would be overcome. Using silicon nanowire (SiNW), germanium nanotube (GeNT), and ZnO nanorod arrays as substrates, high sensitivity, selectivity and reproducibility of SERS signals of the important probes, dye (Bu4N)2[Ru(dcbpyH)2(NCS)2] (N719), and acetaminophen, would be rationally expected. In this research process, we will investigate the method, approach, and process of the PICT between these three semiconductor nanostructures and analytes. By tailoring the specific properties, optimizing parameters, and improving the preparation process, more efficient PICT process as well as stronger enhancement factors from Si, Ge and ZnO nanostructures could be expected. The physical nature of the PICT mechanism-based SERS in semiconductor-molecule system would be revealed. It would be rational to believe that the results of our researches will lay a solid theoretical and experimental foundation for developing a new type SERS-based biological and chemical sensor.

表面增强拉曼散射（SERS）由于具有很高的灵敏性和选择性，在传感领域有着广阔的应用前景。然而，因成本、生物兼容性以及可控性等方面的限制，目前基于电磁增强机制的贵金属（Au、Ag等）SERS并未在传感领域得到广泛的应用。我们在前期理论和实验探索的基础上，提出利用硅、锗和氧化锌半导体纳米结构与检测物之间的电荷转移机制实现SERS效应，从而克服贵金属SERS的应用限制，并以联吡啶钌和对乙酰氨基酚为检测目标，利用上述半导体纳米结构的SERS效应实现对这两种重要目标物高灵敏、高选择、高稳定检测。在此过程中，我们将探索这几种半导体纳米结构与检测物之间的电荷转移途径、方式及过程，通过对半导体材料、结构、表面以及制备工艺的优化，实现纳米结构基底与目标物之间高效电荷转移，并从理论上阐明基于电荷转移机制SERS的物理机理。研究结果将为发展基于电荷转移机制的新型SERS化学和生物传感器奠定坚实的实验和理论基础。

表面增强拉曼散射（SERS）由于具有很高的灵敏性和选择性，在传感领域有着广阔的应用前景。然而，因成本、生物兼容性以及可控性等方面的限制，目前基于电磁增强机制的贵金属（Au、Ag 等）SERS 并未在传感领域得到广泛的应用。我们在前期理论和实验探索的基础上，提出利用氧化锌等半导体纳米结构与检测物之间的电荷转移机制实现SERS 效应，从而克服贵金属SERS 的应用限制。在过去4年里，本项目紧紧围绕半导体表面增强拉曼散射效应及在传感领域应用开展了一系列深入研究。我们首先研究了电化学方法可控制备ZnO纳米棒阵列、金属辅助化学可是法可控制备Si纳米线阵列。并以此为基础，探索了ZnO纳米棒与探针分子4-MPY，PATP、联吡啶钌（N719）之间的光诱导电荷转移（PICT）过程，揭示了探针分子与半导体之间光诱导电荷转移的选择性定则。发现如果探针分子与半导体纳米结构之间能级匹配，在合适的激发光作用下，分子与半导体之间能发生电荷转移，则能观测到半导体表面发生的表面增强拉曼散射（SERS）信号。为了提高检测信号的强度，我们还在ZnO纳米棒表面制备的多晶纳米颗粒，形成了纳米棒/纳米颗粒复合壳层结构，用这种结构的Raman检测基底检测4-MPY，信号增强了3倍。此外，我们通过引入信号分子的方法，实现了用Raman技术检测金属Zn离子。我们还发展了调控纳米间隙的简单方法，增强了Raman检测的灵敏度。在此基础上，构建了基于半导体一维纳米结构表面增强拉曼散射传感器，实现对4-MPY、N719以及对乙酰氨基酚的高灵敏、高选择、高稳定检测。在项目的资助下，我们在Nano letters、Small、Nanoscale等等杂志上发表SCI论文15篇，到目前为止，已被引用100次。申请发明专利11项，获授权发明专利8项。毕业博士6人，其中1人获得中科院院长优秀奖。