25th Anniversary Article: Progress in Chemistry and Applications of Functional Indigos for Organic Electronics

Abstract

Indigo and its derivatives are dyes and pigments with a long and distinguished history in organic chemistry. Recently, applications of this 'old' structure as a functional organic building block for organic electronics applications have renewed interest in these molecules and their remarkable chemical and physical properties. Natural-origin indigos have been processed in fully bio-compatible field effect transistors, operating with ambipolar mobilities up to 0.5 cm(2) /Vs and air-stability. The synthetic derivative isoindigo has emerged as one of the most successful building-blocks for semiconducting polymers for plastic solar cells with efficiencies > 5%. Another isomer of indigo, epindolidione, has also been shown to be one of the best reported organic transistor materials in terms of mobility (∼2 cm(2) /Vs) and stability. This progress report aims to review very recent applications of indigoids in organic electronics, but especially to logically bridge together the hereto independent research directions on indigo, isoindigo, and other materials inspired by historical dye chemistry: a field which was the root of the development of modern chemistry in the first place.

Epindolidiones—Versatile and Stable Hydrogen‐Bonded Pigments for Organic Field‐Effect Transistors and Light‐Emitting Diodes

“…[ 9 ] This composite gate dielectric has a C 0d of ≈40 nF cm -2 . Mobility was calculated from the saturation regime.…”

“…[ 4 ] Hydrogen-bonding as a supramolecular engineering tool is useful to control self-assembly and highly relevant to aqueous and biochemical systems. [ 5,6 ] Recently, we have found that indigo, [ 7 ] and some of its derivatives [ 8,9 ] demonstrate ambipolar transport in organic fi eldeffect transistors (OFETs), with mobility ranging from 0.01-0.4 cm 2 V -1 s -1 . We…”

Aqueous photo(electro)catalysis with eumelanin thin films

“…The electrical properties of biomolecules such as proteins, [1][2][3] DNA, 4 polysaccharides, 5,6 and biopigments [7][8][9] have attracted a growing amount of scientific interest in recent years. This attention is motivated by expanding fundamental understanding of the roles electronic transport may play in biology, as well as the possibility of using bio-origin materials as active components in bioelectronics devices.…”

Advances in the synthesis and application of isoindigo derivatives

“…Such a structure gives rise to the application of these molecules as electron-acceptor materials in organic electronics, focusing on organic photovoltaics (OPVs) and organic field effect transistors (OFETs). [82][83][84] In these studies the high reactivity of bromine atoms in the 6-and 6′-positions of the arene moiety has been widely applied.…”