Investigating the effect of cosolvents on P3HT/O-IDTBR film-forming kinetics and film morphology
Investigating the effect of cosolvents on P3HT/O-IDTBR film-forming kinetics and film morphology
复制标题
研究共溶剂对 P3HT/O-IDTBR 成膜动力学和薄膜形貌的影响
DOI：
10.1016/j.jechem.2020.04.048
复制
发表时间：
2020
影响因子：
13.1
通讯作者：
Qiuju Liang
中科院分区：
文献类型：
--
作者：
Jiangang Liu;Shuyi Zeng;Peng Jing;Kui Zhao;Qiuju Liang
体异质结有机太阳能电池中活性层的形貌对器件性能有决定性的影响。以往的工作表明，溶剂工程是优化活性层形貌的有效方法。然而，筛选合适的溶剂是一项繁琐的任务，我们对如何为特定体系，特别是聚合物/非富勒烯共混体系选择合适的溶剂知之甚少。在这里，我们结合光谱分析在各种溶剂的混合物在成膜过程中，以揭示之间的关系的助溶剂特性，成膜动力学和膜形态。本文选择P3 HT/O-IDTBR共混物作为模型体系，因为其易于大规模合成。选择氯苯作为主溶剂，并根据其沸点将共溶剂分为三类。具有较低bp的共溶剂，如氯仿（CF），可以促进更快的成膜过程，降低域尺寸，但牺牲两种组分的结晶度。对于邻二氯苯（DCB）和1，2，4-三氯苯（TCB）等高bp的共溶剂，P3 HT和O-IDTBR的自组织过程被分离，并延长了其持续时间，形成了高度结晶的纳米互穿网络。然而，具有很高bp的助溶剂，如氯萘（CN），将残留在膜中，并保持P3 HT和O-IDTBR自组织更长的时间，导致较大的相分离。本文系统地研究了助溶剂对成膜动力学的影响，并提出了根据活性层的结晶度和晶畴大小选择助溶剂的指导原则。
The morphology of active layer in bulk heterojunction (BHJ) organic solar cells is decisive to the device performance. Previous works have shown that the solvent engineering is an effective method to optimize the morphology of active layer. However, screening the proper solvent is a tedious task, and we know very little about how to select a proper solvent for a particular system, especially for polymer/non-fullerene blend systems. Here, we combined the spectroscopic analysis in various solvent mixtures during film-forming process to reveal the relationship among the cosolvent characteristics, film-forming kinetics and film morphology. In this article, P3HT/O-IDTBR blend was selected as model system due to being facile synthesized under a large-scale. Chlorobenzene (CB) was selected as main solvent, and the cosolvents were grouped into three categories according to its boiling point (bp) compared to CB. The cosolvents with lower bp, like chloroform (CF), can facilitate a faster film-forming process, reducing the domain size but sacrificing the crystallinity of both components. For the cosolvents with higher bp, like o-dichlorobenzene (DCB) and 1,2,4-trichlorobenzene (TCB), the self-organization process of P3HT and O-IDTBR is separated and its duration was extended, constructing highly crystalline nano-interpenetrating network. However, the cosolvents with very high bp, such as chlornaphthalene (CN), would residue in film and keep P3HT and O-IDTBR self-organizing for longer time, leading to larger phase separation. This work systematically investigated the effect of cosolvent on the film-forming kinetics, and proposed a guideline of how to select a proper cosolvent according to the crystallinity and domain size of active layer.