This review presents emerging strategies for materials scientists to design, prepare and process semiconducting polymers in a more sustainable and eco-friendly manner.

Semiconducting polymers are at the forefront of next-generation organic electronics due to their robust mechanical and optoelectronic properties. However, their extended π-conjugation often leads to materials with low solubilities in common organic solvents, thus requiring processing in high-boiling-point and toxic halogenated solvents to generate thin-film devices. To address this environmental concern, a natural product-inspired side-chain engineering approach was used to incorporate galactose-containing moieties into semiconducting polymers toward improved processability in greener solvents. Novel isoindigo-based polymers with different ratios of galactose-containing side chains were synthesized to improve the solubilities of the organic semiconductors in alcohol-based solvents. The addition of carbohydrate-containing side chains to π-conjugated polymers was found to considerably impact the intermolecular aggregation of the materials and their microstructures in the solid state as confirmed by atomic force microscopy and grazing-incidence wide-angle X-ray scattering. The charge transport characteristics of the new semiconductors were evaluated by the fabrication of organic field-effect transistors prepared from both toxic halogenated and greener alcohol-based solvents. Importantly, the incorporation of carbohydrate-containing side chains was shown to have very little detrimental impact on the electronic properties of the polymer when processed from green solvents.

Green chemistry metrics and life-cycle analysis (LCA) were used to assess inefficiencies in two current organic chemistry experiments conducted in third-year organic chemistry to synthesize (E)-stilbene from benzaldehyde. An alternative Wittig-based, greener, one-pot experiment using the same starting material was selected as a vehicle to introduce the concepts of green chemistry to students. The original learning objectives for the experiment were maintained with additional learning objectives in green chemistry introduced. The theoretical and experimental calculations of all experiments were compared using the standard univariate and multivariate metrics for LCA analysis, to assess the impact of chemical waste generated on the environment. The LCA metrics showed that the Wittig-based experiment addressed eight principles of green chemistry and possessed fewer environmental hazards, produced less waste (E-factor), and had better isomeric purity, mass, and process efficiency including factors such as global warming potential than the current lab methods. Results from a survey of students who conducted all three experiments indicated an enhanced knowledge of green chemistry and an improved sense of chemical and environmental impact. The research provided a platform to introduce sustainable chemistry practices to organic chemistry students at the undergraduate level.

Organic semiconducting polymers are a powerful platform for the design of next-generation technologies due to their excellent optoelectronic properties and solution processability, allowing access to low-cost and scalable manufacturing techniques...

Organic semiconducting polymers are exciting materials for electronic applications because of their good mechanical and optoelectronic properties. A major advantage of organic semiconductors is their solution processability. This allows access to a variety of simple and cost-effective device fabrication methods compared to the expensive, high-temperature processing methods required for silicon-based electronics. However, these materials often have low solubility, which limits their processing to toxic halogenated solvents. Also, their limited solubility often leads to interfacial mixing during device fabrication. This work explores the incorporation of environmentally friendly carbohydrate side chains in conjugated polymers to enhance processability in eco-friendly solvents. Moreover, a mild postprocessing treatment was designed to enable solvent resistance. Isoindigo-based polymers with varied ratios of acetyl-protected galactose side chains were synthesized to improve solubility in o-anisole in the protected state, while inducing solvent resistance through intramolecular hydrogen bonding in the deprotected state. Solvent resistance was confirmed both visually upon submersion in various solvents and using UV−visible spectroscopy. Importantly, the mild basic treatment to achieve solvent resistance has no negative impact on the electronic performance of these materials in organic field-effect transistors, even after subsequent submersion in various solvents, making them a valuable platform for the production of green processable multilayer electronics.