High performance organic field-effect transistors based on single-crystal microribbons and microsheets of solution-processed dithieno[3,2-b:2′,3′-d]thiophene derivatives

Abstract

We present π-conjugated dithieno[3,2-b:2',3'-d]thiophene derivatives that act as high-performance p-type organic semiconductors. These molecules self-organize into single-crystal microribbons or microsheets. High carrier mobilities of up to 10.2 cm(2) V(-1) s(-1) and high on/off ratios of ~10(7) have been achieved in organic single-crystal field-effect transistors.

Self-assembly, Physicochemical, and Field-effect Transistor Properties of Solution-crystallized Organic Semiconductors Based on π-Extended Dithieno[3,2-b:2′,3′-d]thiophenes

“…The absorption spectra of DTT-NP8 and DTT-BT8 are red-shifted, relative to that of phenyl-substituted DTT-8 ( max = 373 nm). 6 This result is consistent with the fact that 2-naphthyl and 2-benzothienyl substitution provides greater π-electron delocalization than does phenyl substitution. Such delocalization is evident from their calculated frontier molecular orbitals; 8 both the HOMO and LUMO are fully delocalized over the entire π-conjugated skeletons for DTT-NP8 and DTT-BT8.…”

“…In our earlier work, 6 we fabricated one-dimensional (1D) charge-transport superstructures based on 2,6-bis(4-octylphenyl)thieno[3,2-b:2¤,3¤-d]thiophene , and successfully demonstrated OFETs with a high hole mobility of 10.2 cm 2 V ¹1 s ¹1 by employing its single-crystal microribbons selfassembled via solution processing. Motivated by this result, we became interested in introducing multiple S£S interactions to π-conjugated oligomers to render an alternative charge-transport pathway other than ππ interactions.…”

“…Motivated by this result, we became interested in introducing multiple S£S interactions to π-conjugated oligomers to render an alternative charge-transport pathway other than ππ interactions. 6 The 2-naphthyl-and 2-benzothienyl-functionalized dithieno[3,2-b:2¤,3¤-d]thiophene derivatives DTT-NP8 and DTT-BT8 (Scheme 1), which are π-expanded analogues of DTT-8, have been designed in the present study. Herein, we report self-assembly, optical, and single-crystal OFET properties of these materials.…”

“…Single-crystal OFETs offer the opportunity to explore their intrinsic chargetransport properties, as the influence of grain boundaries, molecular disorder, and charge traps can be minimized. 4,6,7 Scheme 1 illustrates the synthetic approach to the new semiconducting molecules based on the annulated dithieno[3,2-b:2¤,3¤-d]thiophene core. The SuzukiMiyaura coupling reaction of 1 with 2 in the presence of a catalytic amount of [Pd(PPh 3 ) 4 ] afforded DTT-NP8 in 77% yield, while the synthesis of DTT-BT8 was performed using the Stille coupling between 1 and 3 in 83% yield.…”

“…Organic single-crystal transistors exhibited fieldeffect mobilities as high as 0.54 cm 2 V ¹1 s ¹1 and on/off current ratio of ca. 10 6 .…”