Conjugated polymers based on alkylthiophene-substituted derivatives of benzothieno[3,2-b][1]benzothiophene

Abstract

A comparative study of conjugated polymers based on alkylthiophene-functionalized BTBT is presented. Two synthetic routes were explored: oxidative homopolymerization and Stille polycondensation. A series of polymers incorporating 0, 1, and 2 thiophene spacers was synthesized to systematically investigate the spacer length effect on the properties. The optical and electrochemical properties were characterized by UV–vis spectroscopy and cyclic voltammetry. Increasing the spacer length leads to a gradual narrowing of the optical bandgap and an increase in the HOMO level from -5.4 eV to -5.0…-5.1 eV, while the LUMO levels remain almost unchanged. All polymers exhibit p-type charge transport in organic field-effect transistors (OFETs) under ambient conditions. The highest mobility of 0.001 cm²•V⁻¹•s⁻¹ was achieved for the polymer with a bithiophene spacer.

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References

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