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Mapping the Electronic Structure of Polypyrrole with Image-Based Electrochemical Scanning Tunnelling Spectroscopy
ChemRxiv Pub Date : 2020-10-27 Roger Goncalves, Robert S. Paiva, Andres M R Ramirez, Jonathan A Mwanda, Ernesto C. Pereira, Angel Cuesta
ChemRxiv Pub Date : 2020-10-27 Roger Goncalves, Robert S. Paiva, Andres M R Ramirez, Jonathan A Mwanda, Ernesto C. Pereira, Angel Cuesta
Conducting
polymers are versatile semiconductors whose applications cover a wide range of
devices. Their versatility is due, in addition to other factors, to properties that
can be easily modulated according to the intended application. It is therefore important
to study and map the electronic structure of these materials to allow for a
better correlation between structure and properties. Electrochemical scanning
tunnelling spectroscopy (EC-STS) can be a powerful tool to characterize the electronic
structure of the semiconductor electrolyte interface. In this work we have used
image-based EC-STS (IB-EC-STS) to describe quantitatively the band structure of
an electrochemically deposited polypyrrole (PPy) film. IB-EC-STS located the
band edge of the polymer’s valence band (VB) at 0.95 V vs. RHE (-5.33 eV in the
absolute potential scale) and the intragap polaron states formed when the
polymer is oxidised (doped) at 0.46 V vs. RHE (-4.84 eV in the absolute
potential scale). The IB-EC-STS data were cross checked with electrochemical
impedance spectroscopy (EIS) and Mott-Schottky analysis of the interfacial
capacitance. The DOS spectrum obtained from EIS data is consistent with the
STS-deduced location of the VB and the polarons.
中文翻译:
基于图像的电化学扫描隧道光谱法绘制聚吡咯的电子结构图
导电聚合物是多用途的半导体,其应用范围广泛。除其他因素外,它们的多功能性还取决于可以根据预期应用轻松调节的特性。因此,重要的是研究和绘制这些材料的电子结构,以使结构和性能之间具有更好的相关性。电化学扫描隧道光谱法(EC-STS)可以成为表征半导体电解质界面电子结构的强大工具。在这项工作中,我们使用了基于图像的EC-STS(IB-EC-STS)来定量描述电化学沉积的聚吡咯(PPy)膜的能带结构。IB-EC-STS将聚合物的价带(VB)的带边缘定位在0.95 V对RHE(-5。当聚合物在0.46 V对RHE(绝对电势标度为-4.84 eV)下氧化(掺杂)时,在绝对电势标度中为33 eV)和间隙内极化子态形成。IB-EC-STS数据通过电化学阻抗谱(EIS)和界面电容的Mott-Schottky分析进行交叉检查。从EIS数据获得的DOS光谱与STS推导的VB和极化子的位置一致。
更新日期:2020-10-28
中文翻译:
基于图像的电化学扫描隧道光谱法绘制聚吡咯的电子结构图
导电聚合物是多用途的半导体,其应用范围广泛。除其他因素外,它们的多功能性还取决于可以根据预期应用轻松调节的特性。因此,重要的是研究和绘制这些材料的电子结构,以使结构和性能之间具有更好的相关性。电化学扫描隧道光谱法(EC-STS)可以成为表征半导体电解质界面电子结构的强大工具。在这项工作中,我们使用了基于图像的EC-STS(IB-EC-STS)来定量描述电化学沉积的聚吡咯(PPy)膜的能带结构。IB-EC-STS将聚合物的价带(VB)的带边缘定位在0.95 V对RHE(-5。当聚合物在0.46 V对RHE(绝对电势标度为-4.84 eV)下氧化(掺杂)时,在绝对电势标度中为33 eV)和间隙内极化子态形成。IB-EC-STS数据通过电化学阻抗谱(EIS)和界面电容的Mott-Schottky分析进行交叉检查。从EIS数据获得的DOS光谱与STS推导的VB和极化子的位置一致。