FantastiCOF and the quest for designer 2D polymer bilayers

In December 2025 the FantastiCOF consortium, funded through the European Innovation Council Pathfinder programme, disclosed a key scientific milestone in Nature Chemistry. The team led by Ikerbasque Research Professor Aurelio Mateo-Alonso reports a new synthetic route that yields stacked two dimensional polymer bilayers, or bilayer covalent organic frameworks, with unprecedented structural control directly from monomers. The result is being presented as a potential platform for engineered 2D materials whose layered geometry and molecular design could be tuned for emergent electronic properties.

Why this matters and what was achieved

Stacked 2D materials with controlled interlayer alignment have become a major focus since the discovery that twisting two graphene sheets by a specific 'magic' angle can produce superconductivity. That discovery exposed how small changes in stacking produce large changes in electronic behaviour. FantastiCOF asks whether the same kind of emergent behaviour can be engineered in covalent organic frameworks or COFs. Unlike graphene, COFs are synthetic polymer networks whose chemical structure can in principle be designed with atomic level control. FantastiCOF's reported advance is a method to obtain bilayer COFs that align and stack at defined angles as they form, rather than requiring mechanical stacking of separate layers.

Context in 2D materials research

The work builds on earlier research into on-surface synthesis of 2D polymers and COF monolayers. Collaborations with groups experienced in on-surface reactions were important to the project. The wider field is focused on generating reproducible, high quality multilayer samples that can be integrated into devices. Conventional approaches often rely on mechanically stacking van der Waals layers which raises concerns over sample-to-sample reproducibility and contamination. A chemistry-first route that grows stacked layers in a controlled way addresses some of those issues in principle.

Potential applications and the route to Josephson Junctions

FantastiCOF highlights one possible application area in superconducting electronics, particularly Josephson Junctions. A Josephson Junction is a sandwich of two superconductors separated by a thin non-superconducting barrier. The electronic properties of the barrier and the neighbouring superconductors determine the junction behaviour. The consortium suggests that designer bilayer COFs could be engineered as active layers inside such junctions, offering a new degree of chemical control over barrier properties compared with inorganic or graphitic materials.

Who is in the consortium and how the project was assembled

Aurelio Mateo-Alonso assembled a multidisciplinary team to tackle synthesis, surface science, theory, device fabrication, and materials characterisation. He partnered with researchers experienced in on-surface synthesis and brought in both academic and industrial expertise to confront the difficult task of not only making new materials but also characterising them and attempting device fabrication.

Why this is promising and where caution is needed

The reported ability to encode stacking order in the chemistry of monomers is technically significant. If robust and reproducible it could remove some of the bottlenecks in assembling clean multilayer 2D systems. However the jump from demonstrating controlled stacking to delivering functional superconducting devices is not trivial. Key open questions include whether the stacked COFs show the specific correlated electronic phases seen in twisted graphene, whether films can be made with sufficient lateral size and low defect density for devices, how stable these organic frameworks are under device processing, and how reproducible the synthesis is outside specialist labs.

Next steps for the project and for the field

The FantastiCOF team has signalled that the synthetic milestone is the beginning rather than the end. Following the Nature Chemistry publication the consortium must characterise the electronic properties of the bilayer COFs, attempt device fabrication, and run transport experiments at cryogenic temperatures. If transport data reveals correlated states or superconductivity, that would be a major advance. If not, the chemical control over stacking will still be valuable for tailoring other properties such as optical response, magnetism, or topological effects.

Perspectives from the team and project culture

In an interview for the EIC Coffee Break series Aurelio Mateo-Alonso described a career-long interest in molecular architecture and the connection between atomically precise structure and material properties. He emphasised the collaborative nature of the consortium and credited the EIC Pathfinder Open programme as an enabler for high risk, multidisciplinary research. Mateo-Alonso also shared practical advice for early career researchers which boiled down to hard work, patience, and optimism.

Takeaways for policy and innovation watchers

FantastiCOF is a useful example of how EIC Pathfinder funding is used to assemble cross-disciplinary teams to pursue speculative but potentially high impact science. The result shows the value of bringing synthetic chemistry together with surface science and device physics. Observers should welcome the technical advance while watching for independent replication, thorough characterisation of electronic properties, and progress on device integration before assigning disruptive status to the breakthrough.

Where to follow the project

Further information about FantastiCOF is available through the Horizon Europe project database and the project website. The Nature Chemistry article contains the experimental details and characterisation data that will be critical for other groups to evaluate and build on the work.

Project summary

FantastiCOF aims to fabricate and implement exotic materials from covalent organic frameworks by controlling monomer connectivity and layer stacking. The consortium seeks to harness molecular design to create stacked 2D polymer bilayers with emergent electronic properties that could find applications in next generation superconducting electronics, while recognising that significant further work is needed to demonstrate device-level performance.