Bipolarons rule the short-range terahertz conductivity in electrochemically doped P3HT

Tsokkou, Dimitra; Cavassin, Priscila; Rebetez, Gonzague; Banerji, Natalie (2022). Bipolarons rule the short-range terahertz conductivity in electrochemically doped P3HT. Materials Horizons, 9(1), pp. 482-491. The Royal Society of Chemistry 10.1039/d1mh01343b

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Doping of organic semiconductor films enhances their conductivity for applications in organic electronics, thermoelectrics and bioe- lectronics. However, much remains to be learnt about the proper- ties of the conductive charges in order to optimize the design of the materials. Electrochemical doping is not only the fundamental mechanism in organic electrochemical transistors (OECTs), used in biomedical sensors, but it also represents an ideal playground for fundamental studies. Benefits of investigating doping mechanisms via electrochemistry include controllable doping levels, reversibility and high achievable carrier densities. We introduced here a new technique, applying in situ terahertz (THz) spectroscopy directly to an electrochemically doped polymer in combination with spectro- electrochemistry and chronoamperometry. We evaluate the intrin- sic short-range transport properties of the polymer (without the effects of long-range disorder, grain boundaries and contacts), while precisely tuning the doping level via the applied oxidation voltage. Analysis of the complex THz conductivity reveals both the mobility and density of the charges. We find that polarons and bipolarons need to co-exist in an optimal ratio to reach high THz conductivity (B300 S cm

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Department of Chemistry, Biochemistry and Pharmaceutical Sciences (DCBP)

UniBE Contributor:

Tsokkou, Dimitra; Cavassin, Priscila; Rebetez, Gonzague Antoine Henri and Banerji, Natalie

Subjects:

500 Science > 540 Chemistry

ISSN:

2051-6355

Publisher:

The Royal Society of Chemistry

Funders:

[18] European Research Council ; [4] Swiss National Science Foundation ; [UNSPECIFIED] University of Bern

Language:

English

Submitter:

Olivier Nicolas Ludovic Bardagot

Date Deposited:

24 Feb 2022 14:27

Last Modified:

24 Feb 2022 14:27

Publisher DOI:

10.1039/d1mh01343b

Related URLs:

PubMed ID:

34904620

BORIS DOI:

10.48350/165168

URI:

https://boris.unibe.ch/id/eprint/165168

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