Mapping the electronic structure of polypyrrole with image-based electrochemical scanning tunneling spectroscopy

Author(s)

Goncalves, Roger ; Paiva, Robert S. ; Ramirez, Andres M. R. ; Mwanda, Jonathan A. ; Pereira, Ernesto C. ; Cuesta, Angel

• Document type: Journal article
• Source: ELECTROCHEMICAL SCIENCE ADVANCES; v. 2, n. 2, p. 9-pg., 2022-04-01.

Abstract

Conducting polymers are 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 for a better correlation between structure and properties. Electrochemical scanning tunneling spectroscopy (EC-STS) can be a powerful tool to characterize the electronic structure of the semiconductor interface. In this work, we have used image-based EC-STS (IB-EC-STS) to describe quantitatively the band structure of an electro-chemically deposited polypyrrole 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 doped, at 0.46 V vs. RHE (-4.84 eV). 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. (AU)

• FAPESP's process: 13/07296-2 - CDMF - Center for the Development of Functional Materials
• Grantee: Elson Longo da Silva
• Support Opportunities: Research Grants - Research, Innovation and Dissemination Centers - RIDC
• FAPESP's process: 14/50249-8 - Green chemistry: sustainable synthetic methods employing benign solvents, safer reagents, and bio-renewable feedstock
• Grantee: Arlene Gonçalves Corrêa
• Support Opportunities: Research Grants - Research Centers in Engineering Program
• FAPESP's process: 15/12851-0 - Graphene modified with RuO2 and/or TiO2: synthesis, characterization and aplication to electrochemical reactions
• Grantee: Mariana Cristina Silva
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)
• FAPESP's process: 17/11986-5 - Generation and storage of New Energy: bringing technological development for the country
• Grantee: Ana Flávia Nogueira
• Support Opportunities: Research Grants - Research Centers in Engineering Program