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

Complementary semiconducting polymer blends (c-SPBs) have been proposed and tested to achieve melt-processed high-performance organic field-effect transistors (OFETs). Prior to this study, melt processing requires temperatures as high as 180 °C. To implement this technique into low-cost and large-area thin-film manufacturing for flexible organic electronics, semiconducting materials meltable at temperatures tolerable by ubiquitous plastic substrates are still needed. We report here the design and melt processing of a c-SPB consisting of a matrix polymer (DPP-C5) and its fully conjugated analogue. By utilizing a siloxane-terminated alkyl chain and a branched alkyl chain as solubilizing groups, the matrix polymer DPP-C5 presents a melting temperature of 115 °C. The resulting c-SPB containing as low as 5% of the fully conjugated polymer could be melt-processed at 130 °C. The obtained OFET devices exhibit hole mobility approaching 1.0 cm²/(V s), threshold voltages below 5 V, and ION/IOFF around 10⁵. This combination of efficient charge-carrier transport and considerably low processing temperatures bode well for melt processing of semiconducting polymer-based organic electronics.