We have fabricated poly[(5,6-difluoro-2,1,3-benzothiadiazol-4,7-diyl)-alt-(3,3000-di(2-octyldodecyl)- 2,20;50,200;500,2000-quaterthiophen-5,5000-diyl)] PffBT4T-2OD/fullerene (C60)/[6,6]-phenyl C71-butyric acid methyl ester (PC71BM) ternary blend films. The thin films have been characterized by atomic force microscope (AFM) and ultraviolet/visible spectroscopy in order to study the influence of C60 doping on the morphological and optical properties of the active layer. The results show the incorporation of C60 into PffBT4T-2OD : PC71BM thin film improves the photovoltaic characteristics and shows preferable morphology. Furthermore, we demonstrate the addition of C60 can suppress bimolecular recombination and thus enhanced FF. This work illustrates a valuable strategy towards thick film OSCs with high-performances.
Perovskite solar cells (PVSCs) based on the hybrid organic/inorganic structure have shown great prospect to the development of low cost, flexible, lightweight, and simple processability. But there are still exist many problems that limit its further commercial applications, such as the low mobility of hole transporting layer (HTL) and the poor stability which caused by the external environment and internal degradation. In this work, we demonstrated that the mixed HTL with poly-TPD and PTAA can increase the performance of p-i-n PVSCs. By doping poly-TPD into PTAA, the devices with mixed HTL show significantly enhancement of short-circuit current and fill factor, with an optimized power conversion efficiency (PCE) obtained over 20% enhancement compared with the control devices with bare PTAA, and the best PCE reaches 14.6%. Detailed analysis shows that the performance enhancement can be explained to the improved perovskite grain size and the increased electron transfer of mixed HTL. As a result, by incorporating poly-TPD with PTAA as the HTL, it provides an effective approach to reach high performance p-i-n PVSCs.