Collaborative Research: A Mechanistic Study of Chemical Enhancement in Surface Enhanced Raman Spectroscopy and Graphene Enhanced Raman Spectroscopy

合作研究：表面增强拉曼光谱和石墨烯增强拉曼光谱化学增强的机理研究

• 批准号: 1708581
• 负责人: Stephen Cronin
• 金额: $ 26.52万
• 依托单位: University of Southern California
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-07-15 至 2021-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1708581&HistoricalAwards=false
• 关键词: Collaborative; Research; Mechanistic; Study; Chemical

With support from the Chemical Measurement and Imaging Program in the Division of Chemistry, Professor Cronin at University of Southern California and Professor Jensen at Pennsylvania State University investigate the use of Raman spectroscopy as a powerful tool that measures the energies of specific bond stretches. This technique provide the unique fingerprint for chemical identification. As such, Raman spectroscopy is extremely useful for a number of applications in chemical, environmental and threat detection monitoring. While a highly useful technique, the Raman scattering cross-section of most molecules is extremely small, and this generally limits its potential uses. Surface Enhanced Raman Scattering (SERS) and Graphene Enhanced Raman Scattering (GERS), the techniques investigated in this research project, can be used to improve the small signal intensities, thus making Raman spectroscopy-related applications more practical. In terms of broader impacts Dr. Cronin creates workshops for Los Angeles high school chemistry teachers. He leverages existing relationships between USC and its neighboring high schools (e.g., USC's Good Neighbors Campaign, Joint Education Project, and the Service Learning Program) to increase the attendance from disadvantaged schools (i.e., central Los Angeles inner city schools) serving underrepresented minority groups. The content of the workshop is reformulated to expose underrepresented students to the results and, more importantly, the excitement of research. Research projects for undergraduate students introduce them to fundamental scientific research and give them confidence to pursue careers in science and engineering. A new module devoted to SERS is developed for a new course at USC on nanoscience and nanotechnology, and their research accomplishments are discussed in class and integrated into the curriculum. Professor Jansen uses a website, nanoHub.org, to share their computational tools with scientists outside of his labs. In this collaboration, Professors Cronin and Jensen investigate the mechanism behind the strong spectroscopic responses observed in two surface-based spectroscopic techniques: Surface Enhanced Raman Scattering (SERS) and Graphene Enhanced Raman Scattering (GERS). They use both experimental and computational tools to carefully isolate the enhanced Raman signals caused by Chemical Enhancement (CE) from those signals caused by ElectroMagnetic Enhancement (EM) in order to understand the CE mechanism. Specifically, Professor Cronin's group at USC performs Raman spectroscopy of single molecules on various SERS substrates, which enables a direct comparison with the theoretical calculations preformed at the Jensen's group at PSU. The Raman spectra are collected under various electrochemical conditions in order to explore the role of the molecule-metal energy level alignment and decouple the vibrational-mode-specific chemical enhancement from the uniform chemical enhancement. Professor Jensen's first principles calculations provide a detailed theoretical framework for interpreting chemical enhancement in SERS and GERS spectra to facilitate a better understanding of the chemical enhancement mechanism. Students in both groups experience the interdisciplinary training opportunities. Both groups' are actively engaged in outreach activities to local high school teachers and general public.

在化学划分的化学测量和成像计划的支持下，南加州大学的克罗宁教授和宾夕法尼亚州立大学的詹森教授调查了使用拉曼光谱作为一种强大工具，以测量特定键伸展的能量。 该技术为化学识别提供了独特的指纹。因此，拉曼光谱对于化学，环境和威胁检测监测的许多应用非常有用。 虽然是一种非常有用的技术，但大多数分子的拉曼散射横截面极小，这通常会限制其潜在用途。表面增强的拉曼散射（SER）和石墨烯增强了拉曼散射（GERS），该研究项目中研究的技术可用于改善小信号强度，从而使拉曼光谱相关的应用更加实用。在更广泛的影响方面，克罗宁博士为洛杉矶高中化学老师创建了研讨会。他利用USC与其邻近高中（例如USC的好邻居运动，联合教育项目和服务学习计划）之间的现有关系，以增加为服务不足的少数群体提供服务不足的弱势学校（即中国洛杉矶内部城市学校）的出勤。研讨会的内容进行了重新校正，以使代表性不足的学生接触到结果，更重要的是研究的兴奋。本科生的研究项目向他们介绍了基础科学研究，并使他们有信心从事科学和工程学的职业。为纳米科学和纳米技术的新课程开发了一个专门针对SER的新模块，他们的研究成就在课堂上讨论并集成到课程中。 Jansen教授使用网站Nanohub.org与实验室外的科学家分享其计算工具。 在这种合作中，Cronin和Jensen教授研究了在两种基于表面的光谱技术中观察到的强光谱反应背后的机制：表面增强的拉曼散射（SERS）和石墨烯增强了拉曼散射（GERS）。 他们使用实验和计算工具仔细隔离了由电磁增强（EM）引起的信号引起的化学增强（CE）的增强的拉曼信号，以了解CE机制。 具体而言，Cronin教授在USC的小组对各种SERS底物进行了单分子的拉曼光谱，这可以直接比较PSU的Jensen组的理论计算。 拉曼光谱是在各种电化学条件下收集的，以探索分子 - 金属能水平比对的作用，并使振动模式特异性化学化学化学化学的化学化学化学均匀增强。 詹森教授的第一原理计算提供了一个详细的理论框架，用于解释SERS和GERS光谱中的化学增强，以促进对化学增强机制的更好理解。两组的学生都有跨学科的培训机会。 这两个团体都积极向当地高中教师和公众进行外展活动。

项目成果

Stacking Independence and Resonant Interlayer Excitation of Monolayer WSe 2 /MoSe 2 Heterostructures for Photocatalytic Energy Conversion

用于光催化能量转换的单层WSe 2 /MoSe 2 异质结构的堆叠独立性和共振层间激发

• DOI: 10.1021/acsanm.9b01898
• 发表时间: 2020
• 期刊: ACS Applied Nano Materials
• 影响因子: 5.9
• 作者: Chen, Jihan;Bailey, Connor S.;Cui, Dingzhou;Wang, Yu;Wang, Bo;Shi, Haotian;Cai, Zhi;Pop, Eric;Zhou, Chongwu;Cronin, Stephen B.
• 通讯作者: Cronin, Stephen B.

Monitoring Local Electric Fields at Electrode Surfaces Using Surface Enhanced Raman Scattering-Based Stark-Shift Spectroscopy during Hydrogen Evolution Reactions

• DOI: 10.1021/acsami.8b11961
• 发表时间: 2018-10-03
• 期刊: ACS APPLIED MATERIALS & INTERFACES
• 影响因子: 9.5
• 作者: Shi, Haotian;Cai, Zhi;Cronin, Stephen B.
• 通讯作者: Cronin, Stephen B.

Probing the Mechanisms of Strong Fluorescence Enhancement in Plasmonic Nanogaps with Sub-nanometer Precision

• DOI: 10.1021/acsnano.0c01973
• 发表时间: 2020-11-24
• 期刊: ACS NANO
• 影响因子: 17.1
• 作者: Song, Boxiang;Jiang, Zhihao;Wu, Wei
• 通讯作者: Wu, Wei

Enhanced Plasma Generation from Metal Nanostructures via Photoexcited Hot Electrons

• DOI: 10.1021/acs.jpcc.1c00765
• 发表时间: 2021-03
• 期刊: Journal of Physical Chemistry C
• 影响因子: 3.7
• 作者: Bofan Zhao;Indu Aravind;Sisi Yang;Y. Wang;Ruoxi Li;Boxin Zhang;Yi Wang;J. Dawlaty;S. Cronin

Monitoring Local Electric Fields using Stark Shifts on Napthyl Nitrile-Functionalized Silicon Photoelectrodes

• DOI: 10.1021/acs.jpcc.0c03966
• 发表时间: 2020-07
• 期刊: Journal of Physical Chemistry C
• 影响因子: 3.7
• 作者: Haotian Shi;Ryan T. Pekarek;Ran Chen;Boxin Zhang;Y. Wang;Indu Aravind;Zhi Cai;L. Jensen;N. Neale;S. Cronin