1 research outputs found
Electronic Properties of Bimetallic Metal–Organic Frameworks (MOFs): Tailoring the Density of Electronic States through MOF Modularity
The development of
porous well-defined hybrid materials (e.g.,
metal–organic frameworks or MOFs) will add a new dimension
to a wide number of applications ranging from supercapacitors and
electrodes to “smart” membranes and thermoelectrics.
From this perspective, the understanding and tailoring of the electronic
properties of MOFs are key fundamental challenges that could unlock
the full potential of these materials. In this work, we focused on
the fundamental insights responsible for the electronic properties
of three distinct classes of bimetallic systems, M<sub><i>x</i>–<i>y</i></sub>M′<sub><i>y</i></sub>-MOFs, M<sub><i>x</i></sub>M′<sub><i>y</i></sub>-MOFs, and M<sub><i>x</i></sub>(ligand-M′<sub><i>y</i></sub>)-MOFs, in which the second metal (M′)
incorporation occurs through (i) metal (M) replacement in the framework
nodes (type I), (ii) metal node extension (type II), and (iii) metal
coordination to the organic ligand (type III), respectively. We employed
microwave conductivity, X-ray photoelectron spectroscopy, diffuse
reflectance spectroscopy, powder X-ray diffraction, inductively coupled
plasma atomic emission spectroscopy, pressed-pellet conductivity,
and theoretical modeling to shed light on the key factors responsible
for the tunability of MOF electronic structures. Experimental prescreening
of MOFs was performed based on changes in the density of electronic
states near the Fermi edge, which was used as a starting point for
further selection of suitable MOFs. As a result, we demonstrated that
the tailoring of MOF electronic properties could be performed as a
function of metal node engineering, framework topology, and/or the
presence of unsaturated metal sites while preserving framework porosity
and structural integrity. These studies unveil the possible pathways
for transforming the electronic properties of MOFs from insulating
to semiconducting, as well as provide a blueprint for the development
of hybrid porous materials with desirable electronic structures