普适的聚合物本体异质结形貌工程策略:氟碳溶剂热浸泡

Universal Morphology Engineering for Organic Bulk Heterojunction:Hot Fluorous Solvent Soaking

聚合物本体异质结太阳能电池的光电转换效率与日俱增,获取理想的给/受体材料双连续互穿网络结构仍然是提升器件性能的关键。近期,上海交通大学钟洪亮团队及其合作者发展了一种氟碳溶剂热浸泡后处理策略,优化了活性层薄膜的形貌。氟碳溶剂热浸泡后处理过程能够对活性层薄膜进行快速且均匀的热退火;并且当所选的氟碳溶剂与薄膜加工残留溶剂在临界温度以上互溶成一相时,该混合溶剂将进一步促进薄膜中给/受体材料的再组装过程,形成更有序的纤维状结构,载流子传输效率更高,吸收光谱也有所红移,光电转换效率显著提升。该方法适用于多种给/受体材料组合,包括聚合物/小分子体系、全聚合物体系、全小分子体系,通过较短时间、较低温度的热浸泡处理便能改善薄膜的形貌,获得优异的光电转换性能。

The power conversion efficiency of polymer solar cells based on bulk heterojunction is gradually increasing.However,to achieve an ideal donor/acceptor morphology with bicontinuous and interpenetrating network structure is still challenging.Recently,Hongliang Zhong’s group at Shanghai Jiao Tong University and the coworkers developed a new posttreatment strategy,namely hot fluorous solvent soaking(HFSS),to optimize the morphology of the active layer.The treatment of HFSS can anneal the active layer quickly and uniformly.When the selected fluorous solvent is miscible with the residue of processing solvent above upper critical solution temperature,the mixed solvent will further promote the reorganization of the donor/acceptor materials in the film,thereby forming a highly ordered fibrous structure.Consequently,the device shows higher carrier mobility and slightly red-shift absorption spectrum,providing an improved photovoltaic performance.This strategy performed with short processing time at relatively temperature is suitable for various combinations of donor/acceptor materials,including polymer/small-molecule systems,all-polymer and all-small-molecule systems.