Aero-propulsion, Mechatronics, and Energy Center, Florida State University , Tallahassee, Florida 32310, United States.
The National High Magnetic Field Laboratory, Florida State University , Tallahassee, Florida 32310, United States.
ACS Appl Mater Interfaces. 2017 Apr 19;9(15):13457-13470. doi: 10.1021/acsami.7b01121. Epub 2017 Apr 5.
Performance of portable technologies from mobile phones to electric vehicles is currently limited by the energy density and lifetime of lithium batteries. Expanding the limits of battery technology requires in situ detection of trace components at electrode-electrolyte interphases. Surface-enhance Raman spectroscopy could satisfy this need if a robust and reproducible substrate were available. Gold nanoparticles (Au NPs) larger than 20 nm diameter are expected to greatly enhance Raman intensity if they can be assembled into ordered monolayers. A three-phase self-assembly method is presented that successfully results in ordered Au NP monolayers for particle diameters ranging from 13 to 90 nm. The monolayer structure and Raman enhancement factors (EFs) are reported for a model analyte, rhodamine, as well as the best performing polymer electrolyte salt, lithium bis(trifluoromethane)sulfonimide. Experimental EFs for the most part correlate with predictions based on monolayer geometry and with numerical simulations that identify local electromagnetic field enhancements. The EFs for the best performing Au NP monolayer are between 10 and 10 and give quantitative signal response when analyte concentration is changed.
目前，从手机到电动汽车等便携式技术的性能受到锂电池能量密度和寿命的限制。要扩大电池技术的限制，需要在电极-电解质界面处原位检测痕量成分。如果有一种坚固且可重复使用的基底，表面增强拉曼光谱就可以满足这一需求。直径大于 20nm 的金纳米颗粒（Au NPs）如果能够组装成有序的单层，预计将大大增强拉曼强度。本文提出了一种三相自组装方法，成功地制备了粒径范围为 13nm 至 90nm 的有序 Au NP 单层。报道了模型分析物罗丹明的单层结构和拉曼增强因子（EF），以及性能最佳的聚合物电解质盐双（三氟甲烷）磺酰亚胺锂。实验 EF 大部分与基于单层几何形状的预测以及确定局部电磁场增强的数值模拟相关。性能最佳的 Au NP 单层的 EF 值在 10 和 10 之间，当分析物浓度发生变化时，可提供定量的信号响应。
