College of Chemistry, Nanchang University, 999 Xuefu Avenue, Nanchang, 330031, China.
School of Materials Science and Engineering, Nanchang University, 999 Xuefu Avenue, Nanchang, 330031, China.
Macromol Rapid Commun. 2017 Oct;38(20). doi: 10.1002/marc.201700428. Epub 2017 Aug 25.
The halogen-free solvent additive, 1,4-butanedithiol (BT) has been incorporated into PTB7-Th:PC BM, leading to higher power conversion efficiency (PCE) value as well as substantially enhanced thermal stability, as compared with the traditional 1,8-diiodooctane (DIO) additive. More importantly, the improved thermal stability after processing with BT contributes to a higher glass transition temperature (T ) of PTB7-Th, as determined by dynamic mechanical analysis. After thermal annealing at 130 °C in nitrogen atmosphere for 30 min, the PCE of the specimen processed with BT reduces from 9.3% to 7.1%, approaching to 80% of its original value. In contrast, the PCE of specimens processed with DIO seriously depresses from 8.3% to 3.8%. These findings demonstrate that smart utilization of low-boiling-point solvent additive is an effective and practical strategy to overcome thermal instability of organic solar cells via enhancing the T of donor polymer.
无卤溶剂添加剂 1,4-丁二硫醇（BT）已被掺入 PTB7-Th:PCBM 中，与传统的 1,8-二碘辛烷（DIO）添加剂相比，其功率转换效率（PCE）值更高，热稳定性也有显著提高。更重要的是，用 BT 处理后改善的热稳定性有助于通过动态力学分析确定 PTB7-Th 的玻璃化转变温度（T）更高。在氮气气氛中 130°C 热退火 30 分钟后，用 BT 处理的样品的 PCE 从 9.3%降低到 7.1%，接近其原始值的 80%。相比之下，用 DIO 处理的样品的 PCE 从 8.3%严重降低到 3.8%。这些发现表明，通过提高给体聚合物的 T，明智地利用低沸点溶剂添加剂是克服有机太阳能电池热不稳定性的一种有效且实用的策略。
