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

International audienceDevelopment of modern electronic and spintronic technologies depends in large part on the ability to design materials exhibiting switchable magnetic and electrical properties. Here, motivated by the successful demonstration of reversible redox switching of magnetic order and electrical conductivity in 2dimensional metal-organic frameworks (MOFs) based on benzoquinoid linkers, we perform hybrid density functional theory calculations to investigate this phenomenon at the atomistic level. Electronic, magnetic and charge transport properties have been systematically investigated for oxidized and reduced forms of Mn and Fe benzoquinoid frameworks (i.e., (Me 4 N) 2 [Mn 2 L 3 ], (Me 4 N) 2 [Fe 2 L 3 ] and Na 3 (Me 4 N) 2 [Mn 2 L 3 ], Na(Me 4 N) 2 [Fe 2 L 3 ], respectively with deprotonated chloranilic acid as L). We demonstrate that the experimentally observed large increase in electronic conductivity upon ligand-centered reduction in the Mn MOF (10 9 S•cm −1), is due to cooperative effects arising from band gap reduction and the presence of electrons with lower effective mass. Superior conductivity (by at least 3 orders of magnitude) of the redox pair of the Fe benzoquinoid framework as compared to the Mn analog stems from similar factors and, notably, a large increase in electron delocalization for the reduced Fe compound

Optoelectronic Structure and Photocatalytic Applications of Na(Bi,La)S2 Solid Solutions with Tunable Bandgaps

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Full in silico DFT characterization of lanthanum and yttrium based oxynitride semiconductors for solar fuels

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Computational methodology for full in silico design of new semiconductors for water splitting: A DFT study of YTaON2 and YTiO2N

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Electronic structure of iron porphyrin adsorbed to the Pt(111) surface

Systematic density functional theory calculations that treat the strong on-site 3d electron–electron interactions on iron via a Hubbard <i>U</i>_eff = 3.0 eV and the van der Waals (vdW) interactions between the substrate and adsorbate within the vdW-DF framework are employed to study the adsorption of the iron porphyrin (FeP) molecule to the Pt(111) surface. The more accurate vdW-DF-optPBE and vdW-DF-optB88 functionals found the same binding site to be the most stable and yielded binding energies that were within ∼20% of each other, whereas the binding energies computed with the vdW-DF-revPBE functional were substantially weaker. This work highlights the importance of vdW interactions for organometallic molecules chemisorbed to transition metal surfaces. The stability of the binding sites was found to depend upon the number of Fe–Pt and C–Pt bonds that were formed. Whereas in the gas phase the most stable spin state of FeP is the intermediate spin <i>S</i> = 1 state, the high spin <i>S</i> = 2 state is preferred for the FeP–Pt(111) system on the binding sites considered herein. The spin switch results from the elongation of the Fe–N bonds that occur upon adsorption