Chlorination Enabling a Low-Cost Benzodithiophene-Based Wide-Bandgap Donor Polymer with an Efficiency of over 17.

Wang, Hang; Lu, Hao; Chen, Ya-Nan; Ran, Guangliu; Zhang, Andong; Li, Dawei; Yu, Na; Zhang, Zhe et al. · Adv Mater · 2022

basic_science · Level V

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Abstract

Three regioregular benzodithiophene-based donor-donor (D-D)-type polymers (PBDTT, PBDTT1Cl, and PBDTT2Cl) are designed, synthesized, and used as donor materials in organic solar cells (OSCs). Because of the weak intramolecular charge-transfer effect, these polymers exhibit large optical bandgaps (>2.0 eV). Among these three polymers, PBDTT1Cl exhibits more ordered and closer molecular stacking, and its devices demonstrate higher and more balanced charge mobilities and a longer charge-separated state lifetime. As a result of these comprehensive benefits, PBDTT1Cl-based OSCs give a very impressive power conversion efficiency (PCE) of 17.10% with a low nonradiative energy loss (0.19 eV). Moreover, PBDTT1Cl also possesses a low figure-of-merit value and good universality to match with different acceptors. This work provides a simply and efficient strategy to design low-cost high-performance polymer donor materials.