A superior PCE of 7.34% was delivered in the inverted P(FBT-alt-Se2Th2) : PC71BM polymer solar cells.

In this study, we developed a new cathodic buffer layer consisting of a cross -linked [6,6]phenyl-C 61 -butyric styryl dendron ester (C-PCBSD) matrix and an ionic FPI dopant. The incorporation of FPI can improve the electron mobility via an anion induced charge transfer (AIET) mechanism while maintaining the solvent-resistant property of the crosslinked layer. The ZnO combined with C-PCBSD/FPI layer can effectively and universally improve the performance of bulk-heterojunction polymer solar cells (BHJPSCs), planar heterojunction polymer solar cells (PHJPSCs), and organic metallohalide perovskite solar cells (OMPSCs). Furthermore, the insertion of C-PCBSD/FPI layer can improve the thermal stability of the device by preventing the residue moisture in ZnO from diffusing into the CH 3 NH 3 PbI 3 layer in OMPSCs.

Structural analysis of PTh4FBT suggested that the highly crystalline nature of PTh4FBT is related to its zero c-shift co-facial packing.