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Theory for nonlinear conductivity switching in semiconducting organic ferroelectrics
Till Johann1, Weiwei Xie2,3, Sara Roosta2
1Institute for Molecular Systems Engineering and Advanced Materials, Heidelberg University, Im Neuenheimer Feld 225, 69120 Heidelberg, Germany. martijn.kemerink@uni-heidelberg.de.
Physical Chemistry Chemical Physics : PCCP
|June 28, 2024
Summary
This study investigates benzotrithiophene tricarboxamide (BTTTA), an organic semiconductor ferroelectric. Researchers found its conductivity depends on polarization direction, revealing a resistance switching effect due to dipole-field interactions.
Area of Science:
- Organic electronics
- Materials science
- Condensed matter physics
Background:
- Benzotrithiophene tricarboxamide (BTTTA) exhibits unique ferroelectric and semiconducting properties.
- Experimental studies show a polarization direction-dependent bulk conductivity in BTTTA at finite fields.
Purpose of the Study:
- To theoretically investigate the ferroelectric and semiconducting properties of BTTTA.
- To explore the nonlinear coupling between ferroelectricity and semiconductivity in BTTTA.
- To understand the observed polarization direction dependence of conductivity.
Main Methods:
- Molecular dynamics (MD) simulations to study dipole formation and inversion in BTTTA supramolecular columns under an electric field.
- Quantum mechanics/molecular mechanics (QM/MM) scheme to investigate charge carrier mobility in BTTTA stacks.
- Analysis of resistance switching effects in linear and nonlinear transport regimes.
Main Results:
- MD simulations confirm the ferroelectric behavior of BTTTA, consistent with experimental findings.
- A significant resistance switching effect was observed at finite electric fields.
- Hole mobility was approximately twice as large when polarization and electric field were antiparallel compared to parallel orientations.
Conclusions:
- The observed resistance switching is explained by a microscopic ratchet mechanism.
- This mechanism arises from non-equilibrium interactions between oriented dipoles and charge transport direction.
- BTTTA demonstrates potential for applications in electronic devices exploiting polarization-dependent conductivity.
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