| 초록 |
Donor-acceptor (D-A) alternating copolymers have been very successful to produce high performance polymer solar cells (PSCs), but the fixed composition (1:1) between D and A units in the polymers could limit the further enhancement in the performance. Herein, we developed a series of donor-acceptor (D-A) random copolymers composed of different compositions of electron-rich (D) thienyl-substituted benzo[1,2-b:4,5-b’]dithiophene (BDTT) and electro-deficient (A) pyrrolo[3,4-c]pyrrole-1,4-dione (DPP) in order to systematically investigate the effect of the backbone composition on the properties of the polymers. The optical and electrical properties of D-A random copolymers can be controlled by tuning the ratios between BDTT and DPP (4:1, 2:1, 1:1, 1:2, and 1:4) in the polymer backbone. Among them, the PBDTTDPP with D:A ratio of 2:1 (PR2) exhibited the best power conversion efficiency of 5.63%. Interestingly, the PR2 based PSCs outperformed that of alt-PBDTTDPP (1:1) (PCE= 5.03%) (PA). |
