Empa pioneers atomic-precision hybrid of porphyrins and graphene nanoribbons for future quantum and electronic devices

Empa pioneers atomic-precision hybrid of porphyrins and graphene nanoribbons for future quantum and electronic devices

(IN BRIEF) Empa researchers, working with the Max Planck Institute for Polymer Research, have for the first time attached porphyrin molecules with functional metal centers to graphene nanoribbons with atomic precision. Published in Nature Chemistry, the work creates a hybrid system that combines the unique edge magnetism of graphene ribbons with the localized magnetism of porphyrins. This integration enables electronic and magnetic coupling, opening up potential applications ranging from quantum technologies to optical sensing and molecular electronics. The porphyrins’ optical activity means the system can interact with light to reveal or alter electronic states, while chemical modifications could allow highly sensitive detection of target molecules. The breakthrough was made possible through custom precursor molecules and ultra-precise nanofabrication on gold surfaces. Supported by the Werner Siemens Foundation, the team now plans to explore additional metal centers and broader ribbons to expand the system’s capabilities for quantum and electronic technologies.

(PRESS RELEASE) DÜBENDORF, 22-Aug-2025 — /EuropaWire/ — Researchers at Empa’s nanotech@surfaces laboratory have achieved a breakthrough in molecular electronics by binding organic porphyrin molecules, each containing functional metal centers, to graphene nanoribbons with atomic-level precision. The hybrid structure, which couples magnetism and electronic conduction, could pave the way for innovations in quantum technologies, chemical sensing, and advanced optoelectronics. Their findings have been published in Nature Chemistry.

Ultimate precision: With their method, Empa researchers can synthesize the molecular structure with atomic precision, as confirmed by microscopy imaging (top: scanning tunneling microscopy; bottom: non-contact atomic force microscopy). Image: Empa

Porphyrins are versatile organic molecules that play critical roles in biology, from oxygen transport in hemoglobin to photosynthesis in chlorophyll. Depending on the metal atom held at their core, they exhibit a wide range of optical, chemical, and magnetic properties. While chemists have long sought to use porphyrins for electronics, wiring them together with precision has remained a challenge—until now.

The Empa team, working with synthetic chemists from the Max Planck Institute for Polymer Research, successfully attached porphyrins at regular intervals along the zigzag edges of a graphene nanoribbon only one nanometer wide. This carbon “backbone” not only provides conductivity but also carries a unique edge magnetism. “By coupling the localized magnetism of the porphyrin metal centers with the delocalized edge magnetism of the ribbon, we combined two different magnetic behaviors in a single system,” explained Oliver Gröning, deputy head of Empa’s nanotech@surfaces laboratory.

The implications are broad. The nanoribbon acts as both an electrical and magnetic conduit, linking the porphyrins like a nanoscale string of lights. This interconnected system could function as a chain of quantum bits, opening new routes for spin-based quantum information technologies. At the same time, the porphyrins’ natural optical activity enables information to be read or written using light. For example, subtle changes in emitted light could reveal magnetic states, while optical excitation could directly influence electronic conductivity.

Beyond quantum applications, the hybrid structure has potential as a powerful chemical sensor. Porphyrins can be chemically modified to recognize specific molecules, and any binding event directly alters the conductivity of the graphene backbone. “Our system is a toolbox,” said Roman Fasel, head of the laboratory. “It allows us to tune electronic, magnetic, and optical properties depending on the choice of metal centers and functional groups.”

Achieving this structure required highly controlled conditions. Precursor molecules were first synthesized at the Max Planck Institute with porphyrin cores and strategically placed carbon rings. At Empa, these molecules were then “baked” on a gold surface at several hundred degrees Celsius under ultra-high vacuum to form nanometer-precise graphene ribbons. The process yielded atomic precision, as confirmed by advanced microscopy techniques.

With support from the Werner Siemens Foundation, Empa researchers are now expanding their approach by testing different metal centers and wider graphene ribbons, aiming to transform these molecular designer materials into practical components for future electronics and quantum devices.

Media Contacts:

Prof. Dr. Roman Fasel
Empa, nanotech@surfaces
Phone +41 58 765 43 48
roman.fasel@empa.ch

Dr. Oliver Gröning
Empa, nanotech@surfaces
Phone +41 58 765 46 69
oliver.groening@empa.ch

Anna Ettlin
Communications
Phone +41 58 765 47 33
redaktion@empa.ch

SOURCE: EMPA