Gas Adsorption Effects on the Electronic Properties of Two-Dimensional Nickel Bis(dithiolene) Complex

Two-dimensional (2D) metal-organic frameworks (MOFs) are functional materials in electronic devices, due to the tunable electronic properties. Here, using first-principles calculations, we demonstrate that the recently synthesized pi-conjugated nickel bis(dithiolene) complex with a chemical formula Ni3C12S12 can be used to detect poisonous gases, such as CO and NO molecules. The adsorptions of CO and NO molecules on 2D Ni3C12S12 surface lead to a change of electronic structure from semiconducting to metallic, while O-2 cannot. The electronic structure change can be understood from two respects: owing to the strong interaction between Ni atoms and CO or NO molecules, charge transfer from the adsorbed molecules to the nanosheet gives rise to a large upward shift of the Fermi level and the strong orbital hybridization between Ni d orbitals and CO sigma or NO pi* orbitals provides more electronic states around the Fermi level. These results suggest the potential application of 2D MOFs in sensors and electronic devices.