Spontaneous Phase Separation of Poly(3-hexylthiophene)s with Different Regioregularity for a Stretchable Semiconducting Film

초록

Highly regioregular (RR) poly(3-hexylthiophene)s PHTs are known to exhibit excellent electrical properties in comparison to chemically identical but regiorandom (rr) PHTs. In this study, distinct RR (97% and 55%)-graded PHTs are subjected to solution blending to spontaneously separate the high-RR PHT chains from the low-RR PHT media and develop highly conjugated nanodomains in both solution and film. In the spun-cast blend films, the rr PHT matrix imparts sufficient deformability of the channel layer required for stretchable organic thin-film transistors (OTFTs), compared to neat RR PHTs and blends with a deformable polymer. OTFTs including RR PHT/rr PHT blend films show excellent hole mobility (mu) values up to 0.13 cm(2) V-1 s(-1), surpassing that of the best RR PHT films (0.026 cm(2) V-1 s(-1)) fabricated by ultrasound solution pretreatment. Furthermore, a 50% stretched RR PHT/rr PHT film maintains approximate to 55% of its mu value at no strain, while RR PHT films show a sudden decrease in mu even at 10% stretch. The simple blending approach imparts deformability to pi-conjugated polymer films for application in stretchable OTFTs.

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