Charge Transport in Zirconium-Based Metal-Organic Frameworks

Area of Science:

• Materials Science
• Nanotechnology
• Chemistry

Background:

• Metal-organic frameworks (MOFs) are porous crystalline materials with tunable properties.
• MOFs can be functionalized post-synthesis for diverse applications.
• Electrical conductivity is crucial for MOFs in catalysis and sensing but is often lacking.

Purpose of the Study:

• To develop strategies for imparting tunable electrical conductivity to zirconium-based MOFs.
• To enable MOFs for applications requiring efficient charge transport.
• To maintain the inherent porosity of MOFs during conductivity enhancement.

Main Methods:

• Redox-hopping via grafted inorganic clusters or molecular redox couples on zirconium nodes.
• Charge hopping utilizing the redox properties of organic linkers.
• Bandlike electronic conductivity through donor-acceptor charge transfer complexes with guest molecules.
• Introducing molecular oligomers or inorganic clusters as bridges to span MOF crystallites.

Main Results:

• Demonstrated three distinct strategies to achieve tunable electrical conductivity in Zr-MOFs.
• Showcased methods for charge transport at the nanometer to micrometer scale.
• Highlighted the applicability of Marcus's electron transfer theory for predicting conductivity trends.
• Emphasized the retention of molecular-scale porosity across all strategies.

Conclusions:

• Zirconium-based MOFs can be rendered electrically conductive through multiple strategies.
• These conductive MOFs are suitable for advanced applications in energy conversion, catalysis, and sensing.
• The presented approaches are extendable to other MOF compositions.