Air‐Stable Organic Radicals: New‐Generation Materials for Flexible Electronics?

Abstract

In the last few years, air‐stable organic radicals and radical polymers have attracted tremendous attention due to their outstanding performance in flexible electronic devices, including transistors, batteries, light‐emitting diodes, thermoelectric and photothermal conversion devices, and among many others. The main issue of radicals from laboratory studies to real‐world applications is that the number of known air‐stable radicals is very limited, and the radicals that have been used as materials are even less. Here, the known and newly developed air‐stable organic radicals are summarized, generalizing the way of observing air‐stable radicals. The special electric and photophysical properties of organic radicals and radical polymers are interpreted, which give radicals a wide scope for various of potential applications. Finally, the exciting applications of radicals that have been achieved in flexible electronic devices are summarized. The aim herein is to highlight the recent achievements in radicals in chemistry, materials science, and flexible electronics, and further bridge the gap between these three disciplines.

Ultrathin, Ultra‐Conformable, and Free‐Standing Tattooable Organic Light‐Emitting Diodes

“…For example, it should be possible to capitalise on lessons learned in the development of bioelectronics durable implants based on organic materials, [ 42 ] also considering hybrid organic/inorganic encapsulation layers, [ 43 ] or by looking at new appealing novelty, such as air stable radical polymers, recently employed for the fabrication of several organic electronic devices. [ 44 ]…”

Optically actuating ultra-stable radicals in a large π-conjugated ligand constructed photochromic complex

“…Stable radicals in chemical systems have booming applications in catalysis, molecular recognition, lithium ions battery, information storage and optoelectronic devices [5][6][7][8]. Versatile species of stable radicals have been achieved in organic and organometallic structures, such as oxygen-based radicals, sterichindrance carbon-centered radicals, nitronyl nitroxide radi-cals, and spin-delocalized radicals [9][10][11][12]. However, it is yet lacking of safety and convenient switch because the generation of stable radicals was largely depended on redox reactions triggered by chemical reagents or electricity [13].…”

SET and HAT/PCET acid‐mediated oxidation processes in helical shaped fused bis‐phenothiazines

“…[10] This has paved the way to valuable applications, such as the preparation of redox active pH-sensitive polymers. [11] Additionally, organic radicals have been proposed as building blocks for several multifunctional devices, [12,13] including spin filters for molecular spintronic devices, [14,15] because of their relatively long spin coherence length. Thus, the possibility of tailoring the spin filtering exploiting the chiral induced spin selectivity (CISS) effect of the exceptionally stable radical cations obtained from compounds possessing skeleton C, is under development.…”