Hugelmann Philipp, Schindler Werner
Institut für Hochfrequenztechnik und Quantenelektronik, Universität Karlsruhe (TH), 76128 Karlsruhe, Germany.
J Phys Chem B. 2005 Apr 7;109(13):6262-7. doi: 10.1021/jp0403588.
Nanophysics at electrochemical interfaces, probing the physical properties of nanostructures, requires laterally resolved in-situ spectroscopy, in particular voltage tunneling spectroscopy (VTS), which is at present not yet established. In-situ spectroscopy is required to achieve reliable and reproducible measurements of the intrinsic properties of nanostructures in an electrochemical environment, which are mainly determined in small nanostructures by surface atoms rather than bulk atoms. In contrast to tunneling spectroscopy in ultrahigh vacuum, tip and substrate double-layer capacitances as well as Faradaic currents play an important role in voltage tunneling spectroscopy at electrochemical interfaces. Deoxygenation of the electrolyte, fast measurements using appropriate instrumentation, and minimization of the unisolated tip apex and substrate surface areas exposed to the electrolyte are the key parameters to achieve reliable in-situ voltage tunneling spectroscopy data at electrochemical interfaces. The presented data show that bias voltage intervals of more than 1000 mV can be utilized for spectroscopic investigations in aqueous electrolytes, which allow the in-situ study of discrete electronic levels in nanostructures.
电化学界面的纳米物理学，即探测纳米结构的物理性质，需要横向分辨原位光谱技术，特别是电压隧穿光谱（VTS），而目前该技术尚未建立。为了在电化学环境中对纳米结构的本征性质进行可靠且可重复的测量，需要原位光谱技术，这些性质在小纳米结构中主要由表面原子而非体相原子决定。与超高真空中的隧穿光谱不同，在电化学界面的电压隧穿光谱中，尖端和基底的双层电容以及法拉第电流起着重要作用。电解液的脱氧、使用合适仪器进行快速测量以及尽量减少暴露于电解液的未隔离尖端顶点和基底表面积，是在电化学界面获得可靠原位电压隧穿光谱数据的关键参数。所呈现的数据表明，超过1000 mV的偏置电压区间可用于水性电解液中的光谱研究，这使得能够对纳米结构中的离散电子能级进行原位研究。
