Electrical Conductivity of Doped Organic Semiconductors Limited by Carrier-Carrier Interactions

Marten Koopmans, Miina A T Leiviskä, Jian Liu, Jingjin Dong, Li Qiu, Jan C Hummelen, Giuseppe Portale, Michael C Heiber, L Jan Anton Koster*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

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Abstract

High electrical conductivity is a prerequisite for improving the performance of organic semiconductors for various applications and can be achieved through molecular doping. However, often the conductivity is enhanced only up to a certain optimum doping concentration, beyond which it decreases significantly. We combine analytical work and Monte Carlo simulations to demonstrate that carrier-carrier interactions can cause this conductivity decrease and reduce the maximum conductivity by orders of magnitude, possibly in a broad range of materials. Using Monte Carlo simulations, we disentangle the effect of carrier-carrier interactions from carrier-dopant interactions. Coulomb potentials of ionized dopants are shown to decrease the conductivity, but barely influence the trend of conductivity versus doping concentration. We illustrate these findings using a doped fullerene derivative for which we can correctly estimate the carrier density at which the conductivity maximizes. We use grazing-incidence wide-angle X-ray scattering to show that the decrease of the conductivity cannot be explained by changes to the microstructure. We propose the reduction of carrier-carrier interactions as a strategy to unlock higher-conductivity organic semiconductors.

Original languageEnglish
Pages (from-to)56222-56230
Number of pages9
JournalACS Applied Materials & Interfaces
Volume12
Issue number50
DOIs
Publication statusPublished - 16-Dec-2020

Keywords

  • CHARGE-TRANSPORT
  • THERMOELECTRIC-MATERIALS
  • DOPING EFFICIENCY
  • COULOMB GAP
  • POLYMER
  • MOBILITY
  • ORIGIN

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