Influence of selenophene substitution in BDT-based copolymers on molecular packing and charge transport

초록

We report the design and synthesis of two new donor–acceptor copolymers, PBDTT–TPD and PBDTSe–TPD, incorporatingN-alkylthieno[3,4-c]pyrrole-4,6-dione (TPD) as the electron-acceptor unit benzo[1,2-b:4,5-b′]dithiophene (BDT) derivativesincorporating thiophene and selenophene as the electron-donor unit, respectively. To investigate the impact of substitutingsulfur with selenium in the BDT core, we performed comprehensive structural, optical, and electrical characterizations. Compared to PBDTT–TPD, the selenophene-containing PBDTSe–TPD polymer exhibits a narrower optical bandgap, broaderand red-shifted absorption spectra, and enhanced intermolecular interactions. As a result, the organic field-effect transistors(OFETs) fabricated with these polymers show hole mobilities of 0.0058 cm2/V·s or PBDTT–TPD and 0.021 cm2/V·s forPBDTSe–TPD. These results demonstrate that the strong quinoidal character and lower aromaticity of selenophene contributeto improved molecular packing and charge transport properties, highlighting its potential for high-performance organicelectronic materials.

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