A New Genuine Mott Insulator: β-(BEDT-TTF)TaF₆

A New Charge-Ordered Molecular Conductor: κ-(BEDT-TTF)2K+(18-crown-6)[CoII(NCS)4]∙(H2O)

“…However, the measured value for the charge gap retrieved from fitting the linear part of the Arrhenius plot was 0.57 eV (Figure 9, inset). This high value of the charge gap is characteristic of BEDT-TTF conductive salts containing only single-charged (BEDT-TTF) + radical cations (e.g., β-(BEDT-TTF)TaF 6 has ∆E = 0.55 eV [92]). The crystal structure of ET salts is layered, where ET radical cation layers, responsible for electrical conductivity, are alternated with anionic layers, usually insulating.…”

“…However, in salt 1, full charge segregation between two crystallographically unique molecules A and B as well as spatial separation of charged +1 (A) and neutral (B) BEDT-TTF-s provides crystal and electronic structures more resembling cases of salts where only single-charged organic donor radical cations are presented (see above). The latter also possess fully occupied upper band and demonstrate activated type conductivity with the Coulomb energy gap [92].…”

Boundary research between organic conductors and transistors: new trends for functional molecular crystals

“…This contrasts to the neutral BEDT-BDT crystal, 254 which forms a pitched π-stacking similar to that of rubrene, one of the most highperformance OSCs. [255][256][257][258] The salt is a genuine Mott insulator with a hole localised in a molecule without any dimerisation in contrast to representative Mott insulators based on BEDT-TTF with a κ-type dimerised molecular packing, 259 and exhibits semiconducting behaviour because of the strong electronic correlations. The 2D electronic structure of the salt has been confirmed by tight-binding band calculations and magnetic susceptibility measurements.…”