State Key Laboratory of Molecular Engineering of Polymers, Department of Macromolecular Science, Fudan University, Shanghai, 200438, P. R. China.
Macromol Rapid Commun. 2024 Jan;45(1):e2300288. doi: 10.1002/marc.202300288. Epub 2023 Aug 8.
Tailoring the crystal orientation of donor-acceptor (D-A) copolymers is vital for boosting the performance of optoelectronic devices. Despite recent advances in controlling the crystal orientation of D-A copolymers in films, the investigation into their aggregates in solution and the correlation between the solution aggregates and solid-state crystal orientation has been limited. Herein, an effective solvent additive strategy is reported for tuning solution aggregates and the consequent solid-state structures of poly{[N,N'-bis(2-octyldodecyl)-naphthalene-1,4,5,8-bis(dicarboximide)-2,6-diyl]-alt-5,5'-(2,2'-bithiophene)} (P(NDI2OD-T2)). Specifically, the addition of 1-decanethiol (10-thiol) to the P(NDI2OD-T2) chloroform solution promoted the aggregation of P(NDI2OD-T2) chains because of the improved planarization of the backbones, which changed their crystal orientation in the film from coexisting edge-on and face-on to dominant edge-on when produced by drop-casting. The mechanism of this crystal orientation transformation is elucidated based on the interaction between 10-thiol and the side chains of P(NDI2OD-T2). The optical properties of P(NDI2OD-T2) films with different crystalline structures are closely correlated. Notably, the 10-thiol-enabled facile tailoring of the crystal orientation in P(NDI2OD-T2) can be readily applied to other D-A copolymers of interest. The findings of this study highlight a robust solvent additive strategy for regulating solution aggregates and crystal orientation in D-A copolymer films, which have applications in many optoelectronic devices.
对给体-受体（D-A）共聚物的晶体取向进行剪裁对于提高光电设备的性能至关重要。尽管最近在控制 D-A 共聚物薄膜的晶体取向方面取得了进展，但对其在溶液中的聚集以及溶液聚集与固态晶体取向之间的相关性的研究仍有限。在此，报道了一种有效的溶剂添加剂策略，用于调节溶液聚集以及聚{[N，N'-双（2-辛基十二烷基）-萘-1,4,5,8-双（二羧酸二酰亚胺）-2,6-二基]-交替-5,5'-(2,2'-联噻吩)}（P（NDI2OD-T2））的后续固态结构。具体而言，将 1-癸硫醇（10-硫醇）添加到 P（NDI2OD-T2）的氯仿溶液中，由于主链的平面化得到改善，促进了 P（NDI2OD-T2）链的聚集，这导致其在由滴铸制备的薄膜中从共存的边缘到面取向转变为主要的边缘取向。基于 10-硫醇与 P（NDI2OD-T2）侧链之间的相互作用，阐明了这种晶体取向转变的机制。具有不同晶体结构的 P（NDI2OD-T2）薄膜的光学性质密切相关。值得注意的是，通过 10-硫醇实现的 P（NDI2OD-T2）晶体取向的易于调节可容易地应用于其他感兴趣的 D-A 共聚物。该研究结果强调了一种用于调节 D-A 共聚物薄膜中溶液聚集和晶体取向的稳健溶剂添加剂策略，该策略在许多光电设备中有应用。
