Separating Crystallization Process of P3HT and O-IDTBR to Construct Highly Crystalline Interpenetrating Network with Optimized Vertical Phase Separation
Separating Crystallization Process of P3HT and O-IDTBR to Construct Highly Crystalline Interpenetrating Network with Optimized Vertical Phase Separation
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P3HT和O-IDTBR的分离结晶过程构建高度结晶的互穿网络并优化垂直相分离
DOI：
10.1002/adfm.201807591
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发表时间：
2019-11-01
影响因子：
19
通讯作者：
Han, Yanchun
中科院分区：
文献类型：
--
作者：
Liang, Qiuju;Jiao, Xuechen;Han, Yanchun
聚合物非富勒烯小分子受体（SMAs）太阳能电池中，具有互穿网络结构和优化的垂直相分离的形貌在决定电荷传输和收集方面起着关键作用。然而，聚合物和SMA的结晶通常在成膜过程中同时发生，从而干扰彼此的结晶过程，导致具有不期望的横向和纵向相分离的非晶膜。以聚3-己基噻吩（P3 HT）：O-IDTBR共混物为模型体系，提出了通过控制成膜动力学来解决这些问题的方法。在此，具有选择性溶解度和高沸点的共溶剂1，2，4-三氯苯（TCB）被添加到溶液中，导致P3 HT的优先结晶和延长的成膜持续时间。结果，两种组分的结晶度显著增强。同时，P3 HT的优先结晶诱导固-液相分离，从而合理化纳米互穿网络的形成。此外，表面能驱动O-IDTBR富集在阴极附近，P3 HT迁移到阳极。因此，获得了具有适当垂直相分离的高度结晶的纳米互穿网络。最佳形态改善了电荷传输并抑制了双分子复合，将功率转换效率从4.45%提高到7.18%，这是基于P3 HT的二元非富勒烯太阳能电池中的最高性能。
The morphology with the interpenetrating network and optimized vertical phase separation plays a key role in determining the charge transport and collection in polymer:nonfullerene small molecular acceptors (SMAs) solar cells. However, the crystallization of polymer and SMAs usually occurs simultaneously during film-forming, thus interfering with the crystallization process of each other, leading to amorphous film with undesirable lateral and vertical phase separation. The poly(3-hexylthiophene) (P3HT):O-IDTBR blend is selected as a model system, and controlling film-forming kinetics to solve these problems is proposed. Herein, a cosolvent 1,2,4-triclorobenzene (TCB) with selective solubility and a high boiling point is added to the solution, leading to prior crystallization of P3HT and extended film-forming duration. As a result, the crystallinity of both components is enhanced significantly. Meanwhile, the prior crystallization of P3HT induces solid-liquid phase separation, hence rationalizing the formation of the nano-interpenetrating network. Moreover, the surface energy drives O-IDTBR to enrich near the cathode and P3HT to migrate to the anode. Consequently, a highly crystalline nano-interpenetrating network with proper vertical phase separation is obtained. The optimal morphology improves charge transport and suppresses bimolecular recombination, boosting the power conversion efficiency from 4.45% to 7.18%, which is the highest performance in P3HT-based binary nonfullerene solar cells.