Electric-Field-Controlled Dopant Distribution in Organic Semiconductors

Area of Science:

• Organic electronics
• Materials science
• Semiconductor physics

Background:

• Stable electrical doping is crucial for high-performance organic electronic devices.
• Dopant diffusion in organic semiconductors can impact device stability and functionality.

Purpose of the Study:

• To investigate the impact of operating conditions on doped organic semiconductor thin films.
• To study dopant drift in poly(3-hexylthiophene) (P3HT) and Spiro-MeOTAD.
• To explore the reversibility and control of dopant movement.

Main Methods:

• Electrical measurements
• Optical microscopy
• Spatially resolved infrared spectroscopy
• Scanning Kelvin probe microscopy

Main Results:

• Negatively charged dopants drift significantly in P3HT films under an electric field, but not in Spiro-MeOTAD.
• Dopant drift in P3HT leads to dedoping and increased film resistance.
• Estimated dopant mobilities range from 10^-9 to 10^-8 cm^2 V^-1 s^-1.
• Dopant drift is reversible and controllable over micrometers.

Conclusions:

• Dopant drift is a significant dynamic process in doped P3HT films under operating conditions.
• This effect can be harnessed for novel memory device applications.
• Understanding dopant dynamics is essential for designing stable and efficient organic electronic devices.