Molecular light chain opens up paths for quantum technologies
Researchers at Empa have achieved a breakthrough. They have coupled porphyrin molecules to graphene nanoribbons with atomic precision. The result is a hybrid system that combines electronic, magnetic and optical properties, with potential for sensor technology, electronics and quantum applications.
Porphyrins are central building blocks of nature. They form the basis for haemoglobin in the blood or chlorophyll in plants. In combination with metal centers, they acquire versatile chemical and physical properties. Empa researchers have now used this principle to specifically dock porphyrins to a graphene nanoribbon with zigzag edges. The binding was carried out with the utmost precision and forms a kind of molecular chain with precisely defined distances.
Magnetism meets quantum logic
The graphene ribbon has its own edge magnetism, while the metal centers of the porphyrins contribute conventional magnetism. Both systems have been successfully coupled, a decisive step for quantum technological applications. The hybrid material could function as a series of networked qubits in which spins are used as information carriers.
Electronics and optics in one system
The porphyrins are not only magnetically active, but also optically effective. They can emit light, the wavelength of which is influenced by the magnetic state. A kind of molecular light chain that transmits information through color changes. Conversely, the system can be excited by light, which changes the conductivity and magnetism of the graphene ribbon. This opens up a wide range of applications from chemical sensors to innovative electronic components.
Building blocks for the future
The synthesis of these structures requires complex processes. Under ultra-high vacuum and at high temperatures, the precisely designed starting molecules are “baked” on a gold surface to form the chains. Supported by the Werner Siemens Foundation, the Empa team is now working on developing even more versatile systems by varying the metal centers and graphene widths. The aim is to create designer materials that form the basis for future quantum technologies.
The combination of porphyrins and graphene opens up a new class of molecular systems. It combines chemistry, magnetism and optics in nanoscale structures and lays the foundation for the electronics and quantum technology of tomorrow.