Ternary strategy: An analogue as third component reduces the energy loss and improves the efficiency of polymer solar cells

Ternary strategy is a convenient and effective method to boost the performance of polymer solar cells (PSCs). Utilizing a ternary strategy to trade-off between the energy loss and the efficiency of devices however requires further exploration. Here, through the hydroxyl (-OH) and acetoxy (-OCOMe) substitution at beta-position of the IC terminal group, we developed two new synthetic acceptors, BTIC-OH-beta and BTICOCOMe-beta, which were designed to confine the morphology aggregation. Introduction of an analogue as the third component provides a simple but efficient way to further balance the short current density (J(sc)) and open-circuit voltage (V-oc), leading to a champion efficiency based on PBDB-T:PBDB-TF:BTIC-OCOMe-beta, effectively as high as 12.45%. The results were examined mainly in terms of the morphology characterization, electroluminescence external quantum efficiency (EQE(EL)), steady-state photoluminescence (PL) and transient technology. It suggested fine-tuning of the morphology by ratio modulation, reduction of the energy loss, construction of a promising pathway for charge transfer in the ternary system and enhancing the carrier extraction. In this way, a ternary strategy with an analogue donor could provide more routes to higher-quality solar cells. (c) 2022 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences All rights reserved.

Automated summary

Ternary strategy using two new synthetic acceptors with hydroxyl and acetoxy substitution was developed to enhance the performance of polymer solar cells. By fine-tuning the morphology, reducing the energy loss, and constructing a promising pathway for charge transfer, the efficiency of the solar cells was significantly improved.