Tunable electrical conductivity in metal-organic framework thin-film devices

Area of Science:

• Materials Science
• Chemistry
• Nanotechnology

Background:

• Metal-organic frameworks (MOFs) offer tunable porous structures.
• Controlling electrical conductivity in MOFs is crucial for electronic applications.
• Guest molecule infiltration is a strategy to modify MOF properties.

Purpose of the Study:

• To develop a method for achieving tunable electrical conductivity in MOFs.
• To investigate the mechanism of conductivity in infiltrated MOFs.
• To explore potential applications of conductive MOFs.

Main Methods:

• Infiltration of Cu3(BTC)2 (HKUST-1) MOF thin films with 7,7,8,8-tetracyanoquinododimethane (TCNQ).
• Fabrication of thin-film devices for electrical conductivity measurements.
• Spectroscopic analysis and first-principles modeling to understand conductivity origins.

Main Results:

• Achieved tunable, air-stable electrical conductivity over six orders of magnitude.
• Reached conductivity values as high as 7 siemens per meter.
• Identified TCNQ molecules bridging copper paddlewheels as the source of conductivity.

Conclusions:

• The strategy enables significant control over MOF electrical properties.
• The conductive MOFs exhibit strong electronic coupling between framework subunits.
• These materials show promise for conformal electronics, reconfigurable devices, and sensors.