Effect of triphenylamine as electron-donor evenly spaced in 2, 4, 6 and 8 thiophene units of the main chain: synthesis and properties

New Triphenylamine-Based Oligomeric Schiff Bases Containing Tetraphenylsilane Moieties in the Backbone

Three new triphenylamine-based oligomeric Schiff bases (polySB1, polySB2 and polySB3) containing tetraphenylsilane core (TPS-core) in the main chain were obtained from TPS-core-based diamines and bis(4-formylphenyl)phenylamine by a high-temperature polycondensation reaction. These new oligomers were structurally characterized by FT-IR, NMR and elemental analysis. All polySBs were highly soluble in common organic solvents, such as chloroform, tetrahydrofuran and chlorobenzene. Samples showed moderate molecular average molecular weight (Mw) and a high thermal stability above 410 °C. Likewise, polySBs showed absorption near 400 nm in the UV-vis range and photoluminescence. The HOMO levels and band-gap values were found in the ranges of -6.06 to -6.18 eV and 2.65⁻2.72 eV, respectively. The lowest band-gap value was observed for polySB2, which could be attributed to a more effective π-conjugation across the main chain. The results suggest that silicon-containing polySBs are promising wide-band-gap semiconductors materials for optoelectronic applications.

Electronic and structural properties of polymers based on phenylene vinylene and thiophene units. Control of the gap by gradual increases of thiophene moieties

Polymers with phenylene vinylene bonded to thiophene showed different absorption profiles, high thermal stability and a crystalline structure. The HOMO–LUMO can be tuned.