High thermal stability solution-processable narrow-band gap molecular semiconductors.

Area of Science:

• Materials Science
• Organic Electronics
• Polymer Chemistry

Background:

• Conjugated molecules are key components in organic electronics.
• Thermal stability is a critical factor for device longevity and performance.
• Fluorination is a known strategy to tune molecular properties.

Purpose of the Study:

• To investigate the impact of fluorine substitution patterns on the bulk thermal stability of conjugated molecules.
• To evaluate the performance and thermal robustness of fluorinated molecules in field-effect transistor devices.

Main Methods:

• Synthesis of narrow-band gap conjugated molecules with varying fluorine substitution.
• Thermal analysis to assess bulk thermal stability and phase transition temperatures.
• Fabrication and characterization of field-effect transistors incorporating these molecules.

Main Results:

• Increased fluorine substitution led to enhanced bulk thermal stability under inert and ambient conditions.
• Higher fluorine content increased solid-state phase transition temperatures.
• The most fluorinated molecule exhibited a hole mobility of 0.15 cm²/V·s and device thermal stability exceeding 300 °C.
• Improved thermal robustness and device performance correlated with the degree of C-H to C-F substitution.

Conclusions:

• Fluorination is an effective strategy to improve the thermal stability of molecular semiconductors.
• Molecular design with specific fluorine patterns is vital for creating high-performance, durable optoelectronic devices.
• These findings provide a pathway for developing materials suitable for demanding operating environments.