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 language | English |
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Pages (from-to) | 56222-56230 |
Number of pages | 9 |
Journal | ACS Applied Materials & Interfaces |
Volume | 12 |
Issue number | 50 |
DOIs | |
Publication status | Published - 16-Dec-2020 |
Keywords
- CHARGE-TRANSPORT
- THERMOELECTRIC-MATERIALS
- DOPING EFFICIENCY
- COULOMB GAP
- POLYMER
- MOBILITY
- ORIGIN