Developing novel semiconducting nanomaterials can lead to important advances in conformational electronics, reconfigurable electronics, and sensors. However, current inorganic semiconductors lack synthetic tunability, and semiconducting organic polymers lack in long range order and stability. Metal-organic frameworks (MOFs) are a class of nanoporous, crystalline materials composed of organic linkers and metal nodes. MOFs have synthetic tunability, long range order, and thermodynamic stability, overcoming the challenges perturbing inorganic and organic materials. Due to poor orbital overlap, MOFs are traditionally insulators. However, introduction of redox active guest molecules into the MOF pores can bridge the metal nodes of the MOF, resulting in semiconductivity. The doping of Cu-MOF-74 with the guest molecule tetracyanoquinodimethane (TCNQ) resulted in the previously insulating Cu-MOF-74 exhibiting semiconducting behavior. To our knowledge, this is one of three MOFs which becomes semiconductive after introduction of TCNQ. Scanning electron microscopy and powder x-ray diffraction showed the structure of Cu-MOF-74 to be retained following doping.  Raman scans and optical absorbance spectra show charge transfer between TCNQ and Cu-MOF-74. Importantly, the TCNQ@Cu-MOF-74 material had a conductivity of 0.3 S/m and an activation energy of 71.6 meV.<b> </b>

Tunable electrical conductivity in metal-organic framework powders

2019 Spring National Meeting

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