[23a-E206-1~10] 12.4 Organic light-emitting devices and organic transistors

▼ [23a-E206-5] Multi-Band Charge Transport in Bent-Shaped p-Type Organic Semiconductors

〇(P)Craig Yu¹, Shohei Kumagai¹, Tomokatsu Kushida¹, Masato Mitani¹, Chikahiko Mitsui¹, Hiroyuki Ishii², Jun Takeya^1,3, Toshihiro Okamoto^1,4,5 (1.The Univ. of Tokyo, 2.Univ. of Tsukuba, 3.NIMS, 4.PRESTO, JST, 5.CREST, JST)

Keywords:organic semiconductors, multi-band charge transport, organic field-effect transistors

The multi-band charge transport is a well-known phenomenon in conventional inorganic semiconductors, though it is not commonly observed or investigated in organic semiconductors. In this work, we first demonstrate evidence of multi-band charge transport in the high-performance decyl-dinaphtho[2,3-d:2’,3’-d’]benzo[1,2-b:4,5-b’]dithiophene (C₁₀–DNBDT–NW), and present a new bent-shaped bis(naphtho[2',3':4,5]thieno)[2,3-b:2',3'-e]pyrazine (BNTP) π-electron system to induce more pronounced multi-band charge transport by incorporating the pyrazine moiety. With effective substituent engineering, the favorable two-dimensional herringbone assembly can be obtained, and the decylphenyl-substituted BNTP (C₁₀Ph–BNTP) demonstrates large electronic couplings in the herringbone assembly involving the highest, second, and third highest occupied molecular orbitals. C₁₀Ph–BNTP further shows enhanced charge-transport capability when the electronic couplings of all three occupied molecular orbitals are taken into considerations, which results in high hole mobility up to 9.6 cm² V^–1 s^–1 in single-crystalline thin-film organic field-effect transistors. Our present study provides a viable molecular design strategy for inducing multi-band charge transports in OSCs.