Researchers from CSIC-UPV/EHU, the University of the Basque Country (UPV/EHU), the Technical University of Munich, the University of Nebraska–Lincoln, Al-Azhar University, and the Donostia International Physics Center (DIPC) have reported the creation of a previously unrealized two-dimensional (2D) carbon allotrope that integrates graphene’s structure with precisely engineered nanopores and biphenylene segments.
This new material bridges the gap between ideal graphene sheets and more complex, functional carbon architectures, opening promising avenues for next-generation applications in nanoelectronics and chemical sensing.
The allotrope was synthesized as a nanoporous graphene (NPG) network featuring periodically spaced biphenylene segments. Whereas graphene consists solely of hexagonally bonded carbon atoms, biphenylene incorporates four-, six-, and eight-membered rings. Through a carefully designed bottom-up approach, the researchers grew nanoporous graphene nanoribbons on a gold surface under ultra-high vacuum. Upon controlled heating, the ribbons fused laterally, forming an extended sheet where graphene- and biphenylene-like domains are seamlessly interconnected.
This achievement represents an exceptional level of atomic precision. Unlike conventional materials synthesis, which can introduce random defects, this strategy yields a structurally well-defined material at the atomic scale. The inclusion of periodic pores and non-hexagonal motifs enables fine control over both electronic properties and chemical reactivity.
The introduction of nanopores disrupts the continuous carbon network of graphene, significantly modifying its electronic band structure. While pristine graphene lacks a bandgap - behaving as a semimetal - this new architecture exhibits a semiconducting bandgap, as confirmed by scanning probe microscopy and theoretical calculations. Distinct regions of the network display different electronic behaviors, offering multiple pathways for property tuning.
In addition to adjustable electronic properties, the nanoporous design enhances chemical functionality. The pores create reactive sites that interact readily with gas molecules such as carbon monoxide, demonstrating potential for selective molecular detection. Such properties make the material a compelling candidate for use in sensing technologies related to environmental monitoring, diagnostics, and industrial control.
Another noteworthy feature is the stability of the material under ambient air and oxygen exposure—an important improvement over many air-sensitive 2D materials. This robustness suggests strong potential for practical deployment outside controlled laboratory conditions.
Overall, this study represents a significant advance in the design and synthesis of carbon-based nanomaterials. By combining atomic-level precision, tunable band structure, and chemical versatility, the researchers have established a new platform for exploring functional 2D carbon materials with real-world technological applications.
