To realize the application of organic solar cells (OSCs), an emphasis must be placed on reducing material cost, which is one of the golden triangle elements. One key strategy to address this issue is to optimize the synthesis method of active layer materials. Herein, a convenient synthetic route of thieno[3,4-c]pyrrole-4,6-dione (TPD) acceptor unit derivatives was developed, which greatly shortens the synthetic costs of relevant polymer donors (PDs). Relying on the designed synthetic route, two TPD-based PDs, PTTB-H and PTTB-F, were synthesized. Both PDs without and with fluorine substitution possess similar optical properties, but PTTB-F exhibits deeper molecular energy levels and stronger aggregation behavior in the solid state. The OSCs based on PTTB-F with weaker intermolecular forces in comparison to PTTB-H show a decent PCE of 18.06% in blending with small molecule acceptor L8-BO, which improves the open-circuit voltage and shapes suitable phase separation morphology. Further studies showed that PTTB-F could match with multiple acceptors and exhibit promising device performances. This study presents a low-cost approach to synthesizing electrondeficient TPD units for constructing PD materials with excellent universality and superior performance.
Figure 1. The molecular structures of the synthesized PDs PTTB-H and PTTB-F.
Figure 2. The statistics of device efficiencies based on PTTB-F, PM6, and D18 with various narrow bandgap acceptors.
This work was financially supported by the National Natural Science Foundation of China (NSFC) (Grant No. 52061135206 and 22279094) and the Fundamental Research Funds for the Central Universities.
Original link: https://doi.org/10.1039/D3EE01317K
