Simultaneous Improvements in Efficiency and Stability of Organic Solar Cells via a Symmetric-Asymmetric Dual-Acceptor Strategy

摘要

Simultaneously achieving improvements in power conversion efficiency (PCE)and stability is the main task of the current development stage of organicsolar cells (OSCs). This work reports a symmetry–asymmetry dual-acceptor(SADA) strategy to construct ternary devices, which is found to be feasiblefor increasing both the PCE and the operational lifetime of OSCs. In thiscontribution, the symmetric acceptor L8-BO and the asymmetric acceptorBTP-S9 are blended in equal proportions with polymer donor PM6 for theconsideration of absorption spectrum complementarity and cascade energeticalignment. In addition, the features of crystallinity and miscibility of thedual-acceptor deliver optimized morphology lead to a high PCE of 18.84. Inaddition, the asymmetric acceptor BTP-S9 with a larger dipole moment showstighter molecular stacking and longer crystal correlation length, which favorintrinsic molecular photostability, and further consolidate the operationallifetime of OSCs when coordinated with L8-BO. This work demonstrates theefficacy of the SADA strategy for constructing efficient and stable OSCs.