Thermoactivated Electrical Conductivity in Perylene Diimide Nanofiber Materials

Area of Science:

• Materials Science
• Organic Electronics
• Semiconductor Physics

Background:

• Thermoactivated electrical conductivity is crucial for organic electronic devices.
• Perylene tetracarboxylic diimide (PTCDI) derivatives are promising organic semiconductors.
• Understanding charge transport mechanisms in PTCDI nanofibers is essential for device optimization.

Purpose of the Study:

• To investigate the thermoactivated electrical conductivity of PTCDI nanofibers.
• To analyze the impact of molecular structure (donor-acceptor vs. symmetric) on charge transport.
• To explore the influence of temperature, phase transitions, and light illumination on conductivity.

Main Methods:

• Fabrication of PTCDI nanofibers from donor-acceptor (D-A) and symmetric substituted PTCDIs.
• Measurement of electrical conductivity in the dark and under visible light illumination.
• Analysis of activation energy and its dependence on temperature and material properties.

Main Results:

• D-A PTCDI nanofibers exhibited higher activation energy than symmetric PTCDI nanofibers due to increased material disorder.
• Heating nanofibers above 85 °C significantly increased activation energy due to the polaronic effect.
• Visible light illumination increased charge carrier density in D-A PTCDI nanofibers, reducing activation energy.

Conclusions:

• Material disorder, particularly D-A charge-transfer and dipole-dipole interactions, significantly affects thermoactivated charge hopping in PTCDI nanofibers.
• Phase transitions and polaronic effects play a critical role in modulating electrical conductivity at elevated temperatures.
• Light illumination offers a method to tune charge carrier density and reduce activation energy in D-A PTCDI systems.