Charge Transport and Extraction of Bilayer Interdiffusion Heterojunction Organic Solar Cells

摘要： Bilayer interdiffusion heterojunction with the structure of donor-rich region near the anode and acceptor-rich region near the cathode, could weaken energy level barrier between active layer and electrode, and improve the performance of organic solar cells. In this study, the poly (3-hexylthiophene) (P3HT) / [6:6]-phenyl-C61-butyric acid (PC61BM) bilayer interdiffusion heterojunction organic solar cells were prepared by using orthogonal solvent method, and the charge transport and extraction characteristics were investigated detailedly. The transient photovoltage/transient photocurrent measurements showed that the bilayer interdiffusion heterojunction devices have longer carrier recombination lifetime and shorter charge extract time, and higher carrier mobility of bilayer interdiffusion device was verified by photo-induced charge carrier extraction by linearly increasing voltage technology. The results indicated that the improved heterojunction structure of bilayer interdiffusion devices could reduce carrier recombination and improve charge transport and extraction efficiency. The performance of bilayer interdiffusion device was enhanced obviously, and about 19.8 % power conversion efficiency improvement was achieved as compared with the bulk device. Bilayer interdiffusion heterojunction provide an efficient device structure to optimize performance of organic solar cells.