Fluorinations play the momentous impact in tuning the optical absorption, energy levels, aggregation and microstructurally morphology. Two acceptor-donor-acceptor (A-D-A) non-fullerene small molecular acceptors (SMAs), namely, 2T-(PDI-HD)₂ and F2T-(PDI-HD)₂, by incorporating two fluorine atoms into the central 2,2′-bithiophene linked core, were synthesized. The resultant PDI-based SMAs had excellent thermo- and photo-stability, wide absorption ranging from 300 to 700 nm, and E_LUMOs of −3.71 to −3.84 eV. It was demonstrated that the enhanced molar absorption coefficient, elevated E_LUMO, slightly strengthened film aggregation and lowered miscibility with donor PTB7-Th were observed after incorporating fluorine atom onto the SMAs. Further surface electrostatic potential (ESP) calculation elucidated that the fluorination could increase molecular polarity and maximize the ESP difference between PTB7-Th and SMAs, facilitating exciton dissociation and the charge transport. Accordingly, an 39.01% improved PCE from 1.82% to 2.53% was yielded in PTB7-Th:F2T-(PDI-HD)₂ based device, mainly benefitting from 26.17% enhanced J_SC and 22.82% elevated FF even if the adverse condition of decreased V_OC. This improvement was profited from the increased absorption coefficient, enhanced electron mobility as well as favorable microstructurally morphology. The results demonstrated that inserting fluorine atoms into the central linked core was an effective strategy to improve the device performance.

氟化在调节光吸收、能级、聚集和微观结构形态方面发挥着重大影响。两个受体-供体-受体 (ADA) 非富勒烯小分子受体 (SMA)，即 2T-(PDI-HD) ₂和 F2T-(PDI-HD) ₂，通过将两个氟原子合并到中心 2,2 '-联噻吩连接的核心，被合成。所得的基于 PDI 的 SMA 具有优异的热稳定性和光稳定性，吸收范围从 300 到 700 nm，E _LUMO s 为 -3.71 到 -3.84 eV。结果表明，增强的摩尔吸收系数，提高了E _LUMO，在将氟原子结合到 SMA 上后，观察到略微增强的膜聚集和降低与供体 PTB7-Th 的混溶性。进一步的表面静电势 (ESP) 计算表明，氟化可以增加分子极性并使 PTB7-Th 和 SMA 之间的 ESP 差异最大化，促进激子解离和电荷传输。因此，在基于 PTB7-Th:F2T-(PDI-HD) ₂的设备中，PCE 提高了 39.01%，从 1.82% 提高到 2.53% ，主要得益于 26.17% 的J _SC增强和 22.82% 的FF提高，即使在不利条件下减小V _OC. 这种改进得益于吸收系数的增加、电子迁移率的增强以及有利的微观结构形态。结果表明，将氟原子插入中央连接核是提高器件性能的有效策略。