Unraveling Unprecedented Charge Carrier Mobility through Structure Property Relationship of Four Isomers of Didodecyl[1]benzothieno[3,2-b][1]benzothiophene

The structural and electronic properties of four isomers of didodecyl[1]benzothieno[3,2- b ][1]benzothiophene was investigated. FI-TRMC measurements enabled us to probe the local intrinsic charge carrier transport of those materials, among which 2,7-didodecyl[1]benzothieno[3,2- b][1]-benzothiophene was found to exhibit a strikingly high average interfacial mobility demonstrate that the transport in second isomer operates within the band regime, which we associate with the 2D character of the crystal and the limited thermal fluctuations in electronic transfer integrals. Bulk structure determination of the different BTBT derivatives was realized by single-crystal X-ray diffraction. Classical mobility measurement in OFETs on polycrystalline thin films only confirms the well-established good charge transport properties of second isomer. Devices made from one, three and fourth isomers strongly impacted by their extremely deep ionization potentials, hampering the injection of charges within the accumulation layer. The use of higher electric fields (higher charge carrier density) certainly make the carriers to get strongly attracted by the interface where they have to be subjected to scattering effects.