Combination of Counterion Size and Doping Concentration Determines the Electronic and Thermoelectric Properties of Semiconducting Polymers.

Autor: Baustert KN; Department of Chemistry, University of Kentucky, Lexington, KY, 40506, USA., Bombile JH; Department of Chemistry, and Centre for Applied Energy Research, University of Kentucky, Lexington, KY, 40506, USA., Rahman MT; Department of Chemistry, University of Kentucky, Lexington, KY, 40506, USA., Yusuf AO; Department of Chemistry, University of Kentucky, Lexington, KY, 40506, USA., Li R; Brookhaven National Laboratory, Upton, NY, 11937, USA., Huckaba AJ; Department of Chemistry, University of Kentucky, Lexington, KY, 40506, USA., Risko C; Department of Chemistry, and Centre for Applied Energy Research, University of Kentucky, Lexington, KY, 40506, USA., Graham KR; Department of Chemistry, University of Kentucky, Lexington, KY, 40506, USA.
Jazyk: angličtina
Zdroj: Advanced materials (Deerfield Beach, Fla.) [Adv Mater] 2024 Jul; Vol. 36 (29), pp. e2313863. Date of Electronic Publication: 2024 May 19.
DOI: 10.1002/adma.202313863
Abstrakt: In both chemical and electrochemical doping of organic semiconductors (OSCs), a counterion, either from the electrolyte or ionized dopant, balances the charge introduced to the OSC. Despite the large influence of this counterion on OSC optical and electronic response, there remains substantial debate on how a fundamental parameter, ion size, impacts these properties. This work resolves much of this debate by accounting for two doping regimes. In the low-doping regime, the Coulomb binding energies between charge carriers on the OSC and the counterions are significant, and larger counterions lead to decreased Coulomb interactions, more delocalized charge carriers, and higher electrical conductivities. In the high-doping regime, the Coulomb binding energies become negligible due to the increased dielectric constant of the films and a smoothing of the energy landscape; thereby, the electrical conductivities depend primarily on the extent of morphological disorder in the OSC. Moreover, in regioregular poly(3-hexylthiophene), rr-P3HT, smaller counterions lead to greater bipolaron concentrations in the low-doping regime due to the increased Coulomb interactions. Emphasizing the impact of the counterion size, it is shown that larger counterions can lead to increased thermoelectric power factors for rr-P3HT.
(© 2024 Wiley‐VCH GmbH.)
Databáze: MEDLINE
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