Electrochemical Synthesis and Conductivity Fine Tuning of the 2D Iron-Quinoid Metal–Organic Framework

Abstract

Electrically conducting 2D metal–organic frameworks (MOFs) with hexagonal 2D lattices like other 2D van der Waals stacked materials are attracting increasing interest. The conductivity can be effectively regulated through electronic structure adjustment thanks to the chemical and physical flexibility and adjustability of MOFs. In this regard, through a simple and rapid electrochemical method, 2D conductive iron-quinoid MOFs were synthesized. The conductivity of the obtained MOF film reached 1.7(7) S/m. With the increase of reaction time, the 2D network was oxidized partially, and the conductivity decreased down to 0.5(7) S/m. The DFT calculation results showed a narrow bandgap of the 2D crystal cell. Further quantum chemical calculations of the bimetal unit of the iron-quinoid MOF revealed the expansion of the bandgap as the 2D MOF network is gradually oxidized. This work proves the feasibility of fine-tuning macroscopic conductivity from an electronic structure. The combined organic and inorganic chemical structure of MOF materials provides a larger operating space for this fine regulation than that of pure inorganic materials. This conductive 2D iron-quinoid MOF film provides a new option for the development of novel microelectronic devices.