Structure–property relationships in multifunctional thieno(bis)imide-based semiconductors with different sized and shaped N-alkyl ends

Tuning polymorphism in 2,3-thienoimide capped oligothiophene based field-effect transistors by implementing vacuum and solution deposition methods

“…2a) and summarized in Table 1, thin films of C 4 -NT4N deposited at 0.1 Å s À1 by thermal sublimation exhibit ambipolar field-effect transport with saturated electron and hole mobilities up to 4.5 Â 10 À2 cm 2 V À1 s À1 and 6.7 Â 10 À4 cm 2 V À1 s À1 , respectively. In agreement with a previous report on C 4 PMMA films, 16 XRD analysis reveals that thermal sublimation of C 4 -NT4N on HMDS-functionalized silicon dioxide yielded the phase B ( Fig. S1, ESI †).…”

“…Moreover, considering that the bottom contact configuration is usually characterized by less effective charge injection than that of the top contact one, 19 also the hole and electron carrier mobilities are in good agreement with what was previously reported. 16 On the other hand, the threshold for electron transport is higher when HMDS-treated SiO 2 was used instead of PMMA (i.e. a material with a low surface trapping density) as a dielectric layer, confirming that the electron traps cannot be completely passivated through the functionalization with HMDS.…”

“…Lithographically Controlled Wetting (LCW), to pattern and study the electrical properties of C 6 -NT4N, as it is the most soluble of the C n -NT4N series. 16 LCW is a stamp-assisted technique that exploits the selforganizing properties of the materials in a spatially confined system for creating micro and nanostructured thin films replicating the stamp features. LCW has been successfully employed for the integration of soluble organic and metalorganic compounds in OFETs.…”

“…30,31 Since attempts to implement microstructured films in bottom gate/bottom contact transistors have been unsuccessful, OFETs based on microstripes of C 6 -NT4N were fabricated by LCW in a bottom gate/top contact configuration, i.e. the best performing configuration for a C n -NT4N based device, 16 using a perfluorinated polymer (Cytop) as dielectric layer to guarantee the solvent orthogonality ( Fig. 5a).…”

“…15 A wide library of C n -NT4N compounds has been synthesized and characterized to study the effect of the N-alkyl end shape and size on the optical, self-assembly and charge transport properties. 16 We have recently reported on the relationship between the molecular structures and polymorphism properties of C n -NT4N derivatives. 17 Interestingly, C n -NT4N derivatives with an even number of carbon atoms in the alkyl end chains display at least two conformational polymorphs that adopt different molecular packings, namely phase A and phase B, as a consequence of the different conformational arrangement of the 2,3-thienoimide end-moieties with respect to the adjacent thiophene core, i.e.…”