Furan-substituted benzodithiophene-based polymer semiconductors as charge transport materials for organic transistors and nanocrystal photovoltaics

With the tunability of their electronic properties, π-conjugated polymeric semiconductors have been extensively researched for electronic devices. Here, benzo [1,2-b:4,5-b′]dithiophene-based conjugated polymers are synthesized by controlling the contents of thiophene and furan units and their electrical characteristics are reported. The synthesized furan-containing polymers exhibited smoother surface morphology, desirable solubility, deeper highest occupied molecular orbital levels, increased band gap, and improved film crystallinity. The electrolyte-gated organic field-effect transistors using 25 % furan substituted polymer, P2, exhibited a high mobility of over 8 cm² V⁻¹ s⁻¹. Furthermore, AgBiS₂ nanocrystal photovoltaics using P2 as a hole transport material provided a higher efficiency of 5.59 % compared to devices using control polymer without furan substitution (4.30 %). Our work demonstrates significant structure-property relationships for modifying the electrical properties of polymer semiconductors using molecular engineering to achieve high-performing organic electronic devices.