Key Laboratory of Jiangxi Province for Persistent Pollutants, Control and Resources Recycle, Nanchang Hangkong University, 696 Fenghe South Avenue, Nanchang330063, China.
China-Australia Institute for Advanced Materials and Manufacturing (IAMM), Jiaxing University, 899 Guangqiong Avenue, Jiaxing314001, China.
ACS Appl Mater Interfaces. 2023 Feb 15;15(6):8367-8376. doi: 10.1021/acsami.2c22069. Epub 2023 Jan 31.
The field of organic solar cells (OSCs) has acquired rapid progress with the development of nonfullerene acceptors. Interfacial engineering is also significant for the enhancement of the power conversion efficiency (PCE) in OSCs. Among the cathode interfacial materials (CIMs), perylene diimide (PDI) small molecules are promising owing to the excellent electron affinity and electron mobility. Although the well-known PDINN molecule has excellent properties, it has a high planarity formed by an extensive rigid π-conjugated backbone. Because the PDI molecular backbone has a strong tendency to aggregate, it causes the problem of excessive molecular aggregation and stacking, which directly leads to excessive crystallinity. Proper accumulation is beneficial for charge transport, but oversized crystals formed by overaggregation will hinder charge transport, ultimately affecting the film morphology and charge transport efficiency. Modifying the bay position of PDINN is an effective strategy to reduce the planarity, modulate the molecular aggregation, optimize the morphology, and enhance the charge-collecting efficiency. Therefore, PDINN-S was synthesized from PDINN by substituting the hydrogen with thiophene. The optimal PCE in the PM6:Y6 active layer was 16.18% and remained at 80% of the initial value after 720 h in a glovebox. This provides some guidance for exploring CIMs and preparing large-scale OSCs in the future.
有机太阳能电池（OSC）领域在非富勒烯受体的发展下取得了快速进展。界面工程对于提高 OSC 的功率转换效率（PCE）也非常重要。在阴极界面材料（CIM）中，苝二酰亚胺（PDI）小分子由于具有优异的电子亲和力和电子迁移率而备受关注。虽然著名的 PDINN 分子具有优异的性能，但它具有由广泛的刚性π共轭骨架形成的高平面性。由于 PDI 分子骨架有强烈的聚集倾向，这会导致分子聚集和堆积过度的问题，从而导致过高的结晶度。适当的堆积有利于电荷传输，但过度聚集形成的过大晶体将阻碍电荷传输，最终影响薄膜形态和电荷传输效率。修饰 PDINN 的苯并位置是一种有效的策略，可以降低其平面性、调节分子聚集、优化形态并提高电荷收集效率。因此，通过用噻吩取代 PDINN 中的氢，合成了 PDINN-S。在 PM6:Y6 活性层中，最优的 PCE 为 16.18%，在手套箱中放置 720 小时后仍保持初始值的 80%。这为未来探索 CIM 和制备大规模 OSC 提供了一些指导。
