No, conventional metal-organic frameworks (MOFs) are typically not conductive and behave as electrical insulators.
While MOFs possess remarkable properties like high surface area and tunable porosity, their inherent electrical conductivity is generally very low, often less than 10-12 S/cm. This poor conductivity stems from the insulating nature of the organic linkers and the weak electronic coupling between the metal centers within the MOF structure. This severely limits their use in applications that require electrical conductivity, such as electrochemical devices.
However, significant research efforts are underway to enhance the conductivity of MOFs. Strategies include:
- Introducing redox-active metal centers: Utilizing metal ions that can readily change oxidation states can facilitate electron transport through the MOF.
- Incorporating conductive organic linkers: Replacing insulating linkers with conjugated organic molecules can create pathways for electron movement.
- Guest molecule encapsulation: Introducing conductive guest molecules (e.g., tetracyanoquinodimethane - TCNQ) into the MOF pores can significantly enhance conductivity.
- Post-synthetic modification: Chemically modifying the MOF after its synthesis can introduce conductive elements or pathways.
- Construction of composites: Combining MOFs with conductive materials like carbon nanotubes or graphene can create hybrid materials with improved conductivity.
Through these methods, researchers have successfully created conductive MOFs with significantly improved electrical properties, opening up new possibilities for applications in catalysis, sensing, energy storage, and electronics. Therefore, while standard MOFs are insulating, modified versions can exhibit considerable conductivity.
