Flexible ambipolar organic field-effect transistors with reverse-offset-printed silver electrodes for a complementary...

Area of Science:

• Organic electronics
• Flexible electronics
• Semiconductor devices

Background:

• Organic field-effect transistors (OFETs) are key components for flexible electronics.
• Achieving efficient charge injection and transport in OFETs, especially for n-channel operation, remains a challenge.
• Developing complementary circuits on flexible substrates is crucial for integrated electronic systems.

Purpose of the Study:

• To fabricate ambipolar organic field-effect transistors and complementary inverter circuits on flexible substrates using reverse-offset-printing (ROP).
• To investigate the effect of cesium carbonate (Cs2CO3) as an electron-injection/hole-blocking layer on device performance.
• To demonstrate the potential for large-area, inexpensive, and mechanically stable integrated circuits.

Main Methods:

• Fabrication of OFETs and complementary inverter circuits using ROP of silver (Ag) electrodes on a flexible substrate.
• Utilized a diketopyrrolopyrrole-based co-polymer (PDPP-TAT) as the organic semiconductor and poly(methyl methacrylate) as the gate insulator.
• Incorporated cesium carbonate (Cs2CO3) as an interfacial layer via thermal evaporation to enhance n-channel characteristics.

Main Results:

• Achieved ambipolar behavior in OFETs with saturation mobility values of 0.35 cm2 V(-1) s(-1) for p-channel and 0.027 cm2 V(-1) s(-1) for n-channel.
• Demonstrated a complementary inverter circuit fabricated using the ROP process, with selective Cs2CO3 insertion for controlled operation.
• Observed stable device operation under mechanical bending tests with tensile strains up to 0.5%.

Conclusions:

• The integration of ROP and Cs2CO3 interfacial engineering significantly improves n-channel performance in flexible organic transistors.
• The developed complementary inverter circuits exhibit promising characteristics for flexible and large-area integrated electronics.
• These findings highlight the potential for cost-effective, high-performance flexible electronic applications.