Design, Synthesis, and Versatile Processing of Indolo[3,2‐b]indole‐Based π‐Conjugated Molecules for High‐Performance Organic Field‐Effect Transistors

Abstract

A series of indolo[3,2-b]indole (IDID) derivatives comprising the core unit of N , N -dihexyl-IDID with different aromatic and aliphatic substituents at 2-and 7-position are designed and synthesized to construct highperformance organic semiconductors by different processing routes. Structure-property relationship of the derivatives is comprehensively studied in terms of their photophysical, electrochemical, structural, and electrical characteristics. IDID derivatives are either evaporated in vacuum or dissolved in common organic solvents to ensure applicalbility in different processing routes toward outstanding p-type semiconductor fi lms. Among others, the excellently soluble compound 4H4TIDID (with 2-and 7-substituents of 5-hexyl-2,2′-bithiophene moiety, solubility >20 wt% in chloroform), shows the highest fi eld-effect hole mobility of 0.97 cm 2 V −1 s −1 in a device constructed by vacuum-deposition and 0.18 cm 2 V −1 s −1 in device cosntructed by spincoating, respectively. The 2D grazing incidence X-ray diffraction of 4H4TIDID fi lms in both devices identically show the 2D molecular orientation favorable for the high transistor mobility.

Development, Scope, and Applications of Titanium(III)‐Catalyzed Cyclizations to Aminated N‐Heterocycles

“…To highlight the potential for future applications of this cyclization reaction, we investigated whether the 2‐( o ‐bromoaryl)‐substituted amino heterocycles could be cyclized to yield fused bis‐indoles and indolopyrroles. Bis‐indoles have recently gained interest in the field of organic field‐effect‐transistors (OFETs) as potential organic semiconductors . By using our cyclization method it would be possible to gain access to selectively protected, unsymmetric derivatives.…”

“…Only very electron-poor substituents and free alcohol functions appeared to inhibit the reaction. For example, substrates derived fromn icotinaldehyde, vanillin, and salicylic aldehyde as well as ac yanobenzaldimine did not undergo the cyclization reaction (19)(20)(21)(22). Overall, the titanium(III) catalysis has provided for the first time ar eliable approacht oa ccessing free 3-aminoindoles in high yields and purity.T od emonstrate the synthetic potential of this approach for the installation of such aminoheterocycles into targetm olecules, we sought to combine the aminoindole synthesis with the subsequent N-functionalization reactions (Scheme 4).…”

“…Bis-indoles have recently gained interest in the field of organic field-effect-transistors (OFETs) as potential organic semiconductors. [22,23] By using our cyclization method it would be possible to gain access to selectively protected,u nsymmetric derivatives. Indeed, when submitting the Boc-and acetyl-protected aminoindoles 36 and 37 to copper-promoted C-N coupling conditions, [24] the cyclizations to the desired bis-indoles 51 and 52 took place,g iving yields of 78 and 42 %, respectively (Scheme 8).…”

The Influence of Structural Variations on the Heteroacenes Containing Dihydropyrrolo[3,2‐b]pyrrole Core on Their OFET Performances

“…In the past several years, heteroacenes bearing a dihydropyrrolo[3,2‐ b ]pyrrole core have attracted an increasing attention as building blocks for organic light‐emitting diodes (OLEDs), organic solar cells (OSCs), and OFETs . For instance, Park et al . synthesized a dihydropyrrolo[3,2‐ b ]pyrrole based π‐conjugated molecule with an exceptionally field‐effect high hole mobility of 0.79 cm 2 V −1 s −1 .…”

Design and Characterization of New D–A Type Electrochromic Conjugated Copolymers Based on Indolo[3,2-b]Carbazole, Isoindigo and Thiophene Units

“…ICZ is a well-performance electroactive organic chromophore commonly used as a donor due to its more rigid and extended conjugated structure than carbazole and indolo[3,2-b]indole units. [12,13]. Indolo[3,2-b]carbazole derivatives, whose 5,11-position can be substituted by long alkyl, aryl side chains, or other pendant units, contribute to modification of the π–π stacking and lamella structure on the stacked conjugated polymers [14,15,16].…”