The development of non-fullerene acceptors (NFAs) has facilitated the realization of efficient organic solar cells (OSCs) with minimal burn-in losses and excellent long-term stability. However, the role of NFA molecular structures on device stability remains unclear, limiting commercialization of NFA-based OSCs. Herein, the photostability of 10 OSC devices, fabricated with various NFAs (O-IDTBR, EH-IDTBR, ITIC, and ITIC-M) blended with donor polymers (PTB7-Th, PffBT4T-2OD, and PBDB-T), is investigated. O-IDTBR and EH-IDTBR form highly stable devices with all three polymers, whereas ITIC and ITIC-M devices suffer from burn-in losses and long-term degradation. Conformational instability is found to be responsible for the poor photostability of ITIC and ITIC-M, resulting in poor device stability. Twisting and potential breakage of the chemical bond that links the end group to the main backbone of ITIC and ITIC-M molecules causes undesirable conformational changes. Potential strategies to overcome such detrimental photo-induced conformational changes in NFAs are proposed.

非富勒烯受体 (NFAs) 的发展促进了高效有机太阳能电池 (OSC) 的实现，其具有最小的老化损失和出色的长期稳定性。然而，NFA 分子结构对器件稳定性的作用仍不清楚，限制了基于 NFA 的 OSC 的商业化。在此，研究了由各种 NFA（O-IDTBR、EH-IDTBR、ITIC 和 ITIC-M）与供体聚合物（PTB7-Th、PffBT4T-2OD 和 PBDB-T）混合制成的 10 个 OSC 器件的光稳定性. O-IDTBR 和 EH-IDTBR 与所有三种聚合物形成高度稳定的器件，而 ITIC 和 ITIC-M 器件则遭受老化损失和长期降解。发现构象不稳定性是 ITIC 和 ITIC-M 光稳定性差的原因，导致器件稳定性差。将端基连接到 ITIC 和 ITIC-M 分子的主要骨架的化学键的扭曲和潜在断裂会导致不希望的构象变化。提出了克服这种有害的光诱导 NFA 构象变化的潜在策略。