(Invited) conductive 2D Conjugated MOFs for Electronics: Moftronics
Authors: Dong Renhao 
Published: December 2024

The modern electronics have big impact on our daily lives, but which have been mainly dominated by silicon electronics and organic electronics. Is there any other material to balance the requirements and the performance meanwhile showing good stability? We highlight that high-mobility MOFs shall be rising as promising electrode materials for electronics.[1] The concept is shaped as “MOFtronics”. However, how to realize electronic properties in one framework material? If so, how to develop the topological structures of framework electronic material and establish interesting electronic and magnetic structures? How to achieve dimension-controlled films with enhanced charge transport? Finally, how to achieve superior device performance and reliable structure-property relationship?

To address the above key questions, Dong group has focused on the development of layer-stacked 2D conjugated MOFs (2D c-MOFs) for MOFtronics. Firstly, driven by structural design, we have synthesized a series of conjugated planar or curved symmetrical ligands, such as benzene-, triphenylene-, phthalocyanine-, phenanthrotriphenylene-, coronene- and hexabenzocoronene ligands modified by –SH, -NH2 and -OH groups, thus enabling the engineering of pore sizes, topological structures and structure-electronic property relationship associated with band gaps, conductivity and charge mobilities in 2D c-MOFs.[2] Furthermore, we have combined interfacial chemistry and 2D coordination polymerization chemistry toward the preparation of 2D c-MOF films with precision structures and tunable layer numbers (from monolayer to multilayers), such as LB-assisted air-water interfacial synthesis, surfactant-monolayer-assisted interfacial synthesis,[3] liquid-liquid interfacial synthesis[4], liquid-solid interfacial synthesis,[5] and chemical vapor deposition synthesis[6]. One representative iron-bis(dithiolene) 2D MOF (Fe-THT) film with large area (cm2) and multi layers was synthesized at the liquid-liquid interface and exhibited as a p-type semiconductor showing a band-like transport and high mobility over 200 cm2 V-1 s-1.[4] Another representative copper-bis(dithiolene) 2D MOF (Cu-BHT) film was achieved on liquid-Gallium surface under CVD condition[6] and displayed ultra-smooth surface (surface roughness can reach as low as ~2 Å), enabling the formation of high-quality electrical contacts after device integration, leading to a large reduction of contact resistance. Currently, we demonstrate that MOFtronics can exhibit many unique features, such as high crystallinity, high conductivity (up to 103 S cm-1) and charge mobility, tunable band gaps (metals to semimetals to semiconductors), and good stability. Finally, we discover that these features enable them for applications in broad electronic devices such as transistors,[7] photodetectors, thermoelectronics,[8] flexible sensors[9] and energy storage[10]. A few MOFs also display the potential as ferromagnets and spin qubits, which will definitely extend the functions in information technology. We expect that our research could push the development of MOFtronics for facing the current global challenges relevant to the electronics and communications.

References

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