Functional Organic Semiconductors Based on Bay‐Annulated Indigo (BAI)

Abstract

The advancement of organic electronics has been continually pushed by the need for stable and high performance acceptor materials. By utilizing inexpensive and stable indigo dye as a starting material, Bay‐Annulated Indigo (BAI) provides a new motif for the development of semiconducting materials. Modular and straightforward synthesis makes BAI an outstanding platform for molecular design, while excellent stability, strong absorption, and high ambipolar mobility render BAI‐based materials excellent candidates for organic electronics. BAI‐based polymers and small molecules have taken advantage of these properties to show promising results in a variety of applications.

Advances in applying C–H functionalization and naturally sourced building blocks in organic semiconductor synthesis

“…Another strategy is to pre-install the solubilizing group (alkyl chain) on the thiopheneacetyl or phenylacetyl chloride before the annulation reaction. 135,136 The applications of cibalackrot and BAI as organic OSMs or OSM building blocks have been shown in many organic electronic fields, such as OPVs, OFETs, organic lasers, and OLEDs. [135][136][137][138]…”

“…135,136 The applications of cibalackrot and BAI as organic OSMs or OSM building blocks have been shown in many organic electronic fields, such as OPVs, OFETs, organic lasers, and OLEDs. [135][136][137][138]…”

Polymeric near infrared emitters with bay-annulated indigo moieties

“…The LUMO-levels, about À3.5 to À3.9 eV, is closely correlated to the E LUMO = À3.6 eV, previously attributed to the model compound BAI1. 40 CPDTbased polymers also presented smaller band gaps than PBAIBD-1 (built with BDT as donor unit), thus, CPDT may be a stronger electron donor unit than BDT and, therefore, lead to higher HOMO energy levels (Table 2).…”

Indolonaphthyridine: A Versatile Chromophore for Organic Electronics Inspired by Natural Indigo Dye

“…24 The excited state deactivation of indigo can be blocked through the formation of two new rings at the bay positions of the dye (Scheme 1) forming a new chromophore called indolonaphthyridine(dione), which we abbreviate as IND but is also reported in the literature as bay-annulated indigo (BAI). 25 This reaction was first reported in 1914 with the use of phenylacetyl chloride to create a compound named cibalackrot (Scheme 1). 26 Indolonaphthyridine remains highly planar and is electron deficient, while the two newly installed flanking aryl groups (benzenes in the case of cibalackrot) are twisted out of plane but connected by a pathway of conjugation that enables its use in conjugated polymers.…”