Design and Synthesis of a Novel n-Type Polymer Based on Asymmetric Rylene Diimide for the Application in All-Polymer Solar Cells

A novel n-type polymer of PTDI-T based on asymmetric rylene diimide and thiophene is designed and synthesized. The highest power conversion efficiency of 4.70% is achieved for PTB7-Th: PTDI-T-based devices, which is obviously higher than those of the analogue polymers of PPDI-2T and PDTCDI. When using PBDB-T as a donor, an open-circuit voltage (V-OC) as high as 1.03 V is obtained. The results indicate asymmetric rylene diimide is a kind of promising building block to construct n-type photovoltaic polymers.