Design Strategies for Enhanced Conductivity in Metal–Organic Frameworks

Abstract

Metal–organic frameworks (MOFs) are a class of materials which exhibit permanent porosity, high surface area, and crystallinity. As a highly tunable middle ground between heterogeneous and homogeneous species, MOFs have the potential to suit a wide variety of applications, many of which require conductive materials. The continued development of conductive MOFs has provided an ever-growing library of materials with both intrinsic and guest-promoted conductivity, and factors which limit or enhance conductivity in MOFs have become more apparent. In this Outlook, the factors which are believed to influence the future of MOF conductivity most heavily are highlighted along with proposed methods of further developing these fields. Fundamental studies derived from these methods may provide pathways to raise conductivity across a wide range of MOF structures.

Metal-Organic Frameworks for Metal-Ion Batteries: Towards Scalability

“…Nevertheless, there are compounds with the lower band gap possessing hopping electronic conductivity. The mechanisms of electronic transport in MOFs are the following [35][36][37]: through-bond, through-plane, through-space, redox-hopping, and guest-promoted pathways. This provides an opportunity to utilize ZIF-8 (Zn(mIm) 2, where mIm = 2-methylimidazolate), metal-ion batteries, addressing two issues: providing electron transport and insertion/extraction of ions due to redox activity [38][39][40].…”

High-Throughput Predictions of Metal–Organic Framework Electronic Properties: Theoretical Challenges, Graph Neural Networks, and Data Exploration

“…1,2 While much attention has been focused on the use of MOFs for industrial gas storage and separations, 3,4 the design of MOFs with targeted electronic properties has become a topic of recent interest as well. [5][6][7][8] Through a judicious selection of inorganic nodes and organic linkers, MOFs have been proposed for novel (opto)electronic devices, electrocatalysts, photocatalysts, sensors, and energy storage devices, among many other applications. 6,[9][10][11] However, with tens of thousands of MOFs that have been experimentally synthesized 12 and virtually unlimited more that can be proposed, 13 it is often difficult to identify promising MOF candidates with the optimal set of electronic properties.…”

Interplay between Electronic, Magnetic, and Transport Properties in Metal Organic–Radical Frameworks

“…For example, million-fold increase of ff in Fe 2 (DSBDC) and Fe 2 (DOBCD) compared to the Mn analogs was attributed to presence of weakly bound spin-down electrons of the Fe 3+ . 48 Thus, by investigating the phenomenon at the atomistic level, one can provide key insights and engage the rational design of future multifunctional hybrid organic-inorganic materials.. [49][50][51] Here, we use first-principles calculations, based on hybrid density function theory (DFT), to shed new light on the origin of ∆ff in multifunctional Mn and Fe MOFs based on benzoquinoid linkers. After a thorough description of the structural, electronic and magnetic properties of the materials, we use the Boltzmann approach to investigate their transport properties.…”

“…For example, a million-fold increase of σ in Fe 2 (DSBDC) and Fe 2 (DOBCD) compared to the Mn analogues was attributed to presence of weakly bound spin-down electrons of the Fe 3+ . Thus, by investigating the phenomenon at the atomistic level, one can provide key insights and engage in the rational design of future multifunctional hybrid organic–inorganic materials. − …”