Attaining Melt Processing of Complementary Semiconducting Polymer Blends at 130 °C via Side-Chain Engineering.

Area of Science:

• Materials Science
• Organic Electronics
• Polymer Chemistry

Background:

• Melt processing of semiconducting polymer blends (c-SPBs) offers a pathway to high-performance organic field-effect transistors (OFETs).
• Existing methods require high processing temperatures (up to 180 °C), limiting their use with common plastic substrates for flexible electronics.
• There is a need for semiconducting materials meltable at lower temperatures compatible with low-cost, large-area manufacturing.

Purpose of the Study:

• To design and develop a novel complementary semiconducting polymer blend (c-SPB) for melt processing at reduced temperatures.
• To investigate the impact of specific solubilizing groups on the matrix polymer's melting point.
• To evaluate the performance of organic field-effect transistors (OFETs) fabricated from the developed c-SPB.

Main Methods:

• Synthesis of a matrix polymer (DPP-C5) incorporating siloxane-terminated alkyl and branched alkyl chains to lower melting temperature.
• Formulation of a c-SPB using DPP-C5 and a fully conjugated polymer.
• Melt processing of the c-SPB at 130 °C and fabrication of OFET devices.

Main Results:

• The matrix polymer DPP-C5 exhibited a melting temperature of 115 °C.
• The c-SPB, containing as little as 5% of the conjugated polymer, was successfully melt-processed at 130 °C.
• Fabricated OFET devices demonstrated high hole mobility (~1.0 cm²/Vs), low threshold voltages (<5 V), and high on/off ratios (~10⁵).

Conclusions:

• The developed c-SPB allows for efficient melt processing at significantly lower temperatures than previously reported.
• The low processing temperature is compatible with ubiquitous plastic substrates, enabling cost-effective manufacturing of flexible organic electronics.
• The high performance of the resulting OFETs highlights the potential of this approach for advanced organic electronic applications.