Considerations for the sustainable processing of nanomaterials using Cyrene

Cyrene, a bio-derived green solvent, has emerged as a promising sustainable alternative to toxic solvents in the production of electronic nanomaterials. Yet, despite promising early results, little is known about Cyrene’s structural resilience and efficiency during common solution processing steps. Here, we provide a comprehensive evaluation of Cyrene across sonication, thermal treatment, nanomaterial debundling and exfoliation, and network formation, using carbon nanotubes (CNTs) and graphene as model systems. We show that while Cyrene degrades under heating, forming aldol condensates and other by-products, low-power processing mitigates this degradation and can produce yields of ~16% individual CNTs, with two concentration-dependent debundling regimes. For graphene, liquid-phase exfoliation is possible despite solvent degradation, but nanosheets are thicker and longer compared to water-based exfoliation due to the high viscosity. However, degradation products, large aldol condensate crystals in particular, can inhibit the formation of conductive networks. Owing to its high boiling point, high-temperature annealing can leave conductivity-limiting residues but that have low impact on transmittance. As the demand for sustainable materials grows, this work provides critical guidance for integrating Cyrene into scalable nanomaterials pipelines for electronics, energy, and beyond.