Effectively modulating thermal activated charge transport in organic semiconductors by precise potential barrier...

Area of Science:

• Materials Science
• Organic Electronics
• Semiconductor Physics

Background:

• Temperature dependence significantly impacts organic semiconductor properties and applications.
• Modulating this temperature dependence is a key challenge in the field.
• Grain boundary potential barriers are critical for charge transport in organic semiconductors.

Purpose of the Study:

• To develop a strategy for precisely tuning the temperature dependence of charge transport in organic semiconductors.
• To investigate the relationship between grain size, potential barrier height, and temperature sensitivity.
• To demonstrate the application of this strategy in creating highly thermo-sensitive organic field-effect transistors (OFETs).

Main Methods:

• Potential barrier engineering by precisely tuning the effective height of grain boundaries.
• Investigating charge transport behavior across varying grain sizes relative to the Debye length.
• Fabricating and characterizing organic field-effect transistors (OFETs) using dinaphtho[2,3-b:2',3'-f]thieno[3,2-b]thiophene (DNTT).

Main Results:

• Charge transport exhibits maximum temperature dependence when the effective potential barrier height is maximized at a grain size near twice the Debye length.
• Both larger and smaller grain sizes reduce the effective potential barrier height, leading to more thermostable devices.
• A DNTT-based device achieved a high thermo-sensitivity (relative current change) of 155, exceeding standard expectations.

Conclusions:

• Potential barrier engineering offers an effective strategy to modulate temperature dependence in organic semiconductors.
• Optimizing grain size relative to the Debye length is crucial for achieving high thermo-sensitivity.
• Thermo-sensitive OFETs developed through this method demonstrate potential as highly sensitive temperature sensors.