The electropolymerization of several poly(3‐methylthiophene) films in the same used solution and its consequence in their properties

Correa, A. A.; Gonçalves, Roger; Pereira, Rodrigo Lisbôa; Pereira, Ernesto C.

doi:10.1002/app.44368

“…Using the impedance parameters it was possible to propose changes in film morphology of both materials, which are consistent with previous work involving this type of observation [37,63,65]. Thus, from a theoretical point of view, we use DFT calculations to describe, at a molecular level, those changes observed from electrochemical experiments and thus understand the mechanism of self-doping.…”

Section: Computational Modelling Of the Redox Behaviour Of Poma Filmssupporting

confidence: 82%

Properties improvement of poly(o-methoxyaniline) based supercapacitors: experimental and theoretical behaviour study of self-doping effect

Gonçalves

¹

,

Christinelli

²

,

Trench

³

et al. 2017

Electrochimica Acta

View full text Add to dashboard Cite

ABSTRACT:Conducting polymers (CP) are very versatile materials with important properties due to their unique structure, including redox behaviour upon electrochemical polarization. Supercapacitors are among the devices in which CP show a promising performance due to their large specific capacitance. However, the major drawback of these materials is their low durability, which is an inbuilt process caused by ion intercalation, a side effect of the redox process. A viable strategy to increase CP stability is, therefore, the inhibition of the ion intercalation/de-intercalation process. Several strategies have been proposed to minimize this effect, among them self-doping. Self-doping makes the redox process mass-transport independent, decreasing the response time and increasing durability. With this purpose, this work have described the synthesis of layer-by-layer films (LBL) of poly(omethoxyaniline)/poly(3-thiopheneacetic acid) (POMA/PTAA) and contributes to understand how the redox process leads to premature aging, and how self-doping minimizes this problem. The main techniques of characterisation used were electrochemical impedance spectroscopy (EIS) experiments and density functional theory (DFT) calculations. EIS provides important information about the electrochemical behaviour, while DFT calculations allowed to characterize, at the molecular level, the changes in the material structure. The association of both techniques helped to understand how self-doping improves the POMA properties. DFT calculations showed that in the layer-by-layer (LBL) films, the twisting of the polymer chain due to the oxidation is 12% less while the chain shortening is 5% compared with films prepared POMA by casting. The EIS data showed the effect of these molecular changes in the structure; the swelling of the LBL films is 50% less than cast ones. These observations are important because the PTAA layer acts beyond a chargecompensator, working as a backbone structure that mechanically stabilize the POMA layer, leading to an increase in the durability, and improving the electrochemical properties.

show abstract

“…Electrochemical impedance spectroscopy was used to obtain information about the electrochemical and electronic properties of the PPy film. The impedance results were fitted using a transmission line model 24,[27][28][29][30][31] , which is presented in the Supplementary Information (Part 2). A plot of the inverse of the squared capacitance, as obtained from the impedance measurements, can be used to determine the apparent charge-carrier density and the apparent flat-band potential by fitting the data to the Mott-Schottky equation:…”

Section: Stm Characterizationmentioning

confidence: 99%

Mapping the Electronic Structure of Polypyrrole with Image-Based Electrochemical Scanning Tunnelling Spectroscopy

Gonçalves¹,

Paiva²,

Ramírez³

et al. 2020

Preprint

0

View full text Add to dashboard Cite

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.

show abstract

“…Electrochemical impedance spectroscopy was used to obtain information about the electrochemical and electronic properties of the PPy film. The impedance results were fitted using a transmission line model [21,[24][25][26][27][28] , which is presented in the Supplementary Information (Part 2). A plot of the inverse of the squared capacitance (Figure 2a), as obtained from the impedance measurements, can be used to determine the apparent charge-carrier density and the apparent flat-band potential by fitting the data to the Mott-Schottky equation:…”

Section: Electrochemical Characterizationmentioning

confidence: 99%

Mapping the Electronic Structure of Polypyrrole with Image-Based Electrochemical Scanning Tunnelling Spectroscopy

Gonçalves¹,

Paiva²,

Ramírez³

et al. 2020

Preprint

0

View full text Add to dashboard Cite

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.

show abstract

The electropolymerization of several poly(3‐methylthiophene) films in the same used solution and its consequence in their properties

Cited by 10 publications

References 31 publications

Properties improvement of poly(o-methoxyaniline) based supercapacitors: experimental and theoretical behaviour study of self-doping effect

Properties improvement of poly(o-methoxyaniline) based supercapacitors: experimental and theoretical behaviour study of self-doping effect

Mapping the Electronic Structure of Polypyrrole with Image-Based Electrochemical Scanning Tunnelling Spectroscopy

Mapping the Electronic Structure of Polypyrrole with Image-Based Electrochemical Scanning Tunnelling Spectroscopy

Contact Info

Product

Resources

About