Effect of Fluorination on the D-A-D type Hole Transporting Materials for Perovskite Solar Cells

To study the effect of fluorination on hole transporting materials (BTD-Th and BTD-F-Th) for the efficient perovskite solar cells, we designed and synthesized a novel D-A-D type hole transporting molecule having benzo[1,2-c][1,2,5]thiadiazole (BTD) as electron acceptor unit and thiophene (Th) as a simple electron donor unit. The D-A-D molecules BTD-Th and BTD-F-Th were synthesized by palladium(0) catalyzed Stille coupling reaction. The electrochemical band gap of synthesized compounds varies from -1.5 eV to -1.7 eV, Which were ideal for hole transport material (with perovskite active layer) and effective electron blocking layer. The architecture of the perovskite device is glass/ITO/SnO2/CH3NH3PbI3(Perovskite)/Hole Transport Material/Ag.