High power conversion efficiency (PCE) and long-term stability are essential prerequisites for the commercialization of polymer solar cells (PSCs). Small-molecule acceptors (SMAs) are core materials that have led to recent, rapid increases in the PCEs of the PSCs. However, a critical limitation of the resulting PSCs is their poor long-term stability. Blend morphology degradation from rapid diffusion of SMAs with low glass transition temperatures (T_gs) is considered the main cause of the poor long-term stability of the PSCs. The recent emergence of oligomerized SMAs (OSMAs), composed of two or more repeating SMA units (i.e., dimerized and trimerized SMAs), has shown great promise in overcoming these challenges. This innovation in material design has enabled OSMA-based PSCs to reach impressive PCEs near 19% and exceptional long-term stability. In this review, we summarize the evolution of OSMAs, including their research background and recent progress in molecular design. In particular, we discuss the mechanisms for high PCE and stability of OSMA-based PSCs and suggest useful design guidelines for high-performance OSMAs. Furthermore, we reflect on the existing hurdles and future directions for OSMA materials towards achieving commercially viable PSCs with high PCEs and operational stabilities.

中文翻译：

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高效稳定聚合物太阳能电池二聚体和多聚体受体的最新进展与展望

高功率转换效率（PCE）和长期稳定性是聚合物太阳能电池（PSC）商业化的重要先决条件。小分子受体（SMA）是导致 PSC 的 PCE 最近快速增长的核心材料。然而，所得 PSC 的一个关键限制是其长期稳定性差。低玻璃化转变温度（ T _g s）的 SMA 快速扩散导致的共混物形态退化被认为是 PSC 长期稳定性差的主要原因。最近出现的由两个或多个重复SMA单元(即二聚和三聚SMA)组成的寡聚SMA(OSMA)在克服这些挑战方面显示出了巨大的希望。这种材料设计创新使基于 OSMA 的 PSC 能够达到接近 19% 的令人印象深刻的 PCE 和卓越的长期稳定性。在这篇综述中，我们总结了 OSMA 的演变，包括它们的研究背景和分子设计的最新进展。特别是，我们讨论了基于 OSMA 的 PSC 的高 PCE 和稳定性机制，并为高性能 OSMA 提出了有用的设计指南。此外，我们反思了 OSMA 材料在实现具有高 PCE 和运行稳定性的商业上可行的 PSC 方面的现有障碍和未来方向。