| 초록 |
A new series of donor-acceptor (D-A) conjugated random terpolymers (PBDTT-DPP-TPD) were synthesized from electron-rich thienyl-substituted benzo[1,2-b:4,5-b’]dithiophene (BDTT), in conjugation with two electron-deficient units, pyrrolo[3,4-c]pyrrole-1,4-dione (DPP) and thieno[3,4-c]pyrrole-4,6-dione (TPD), of different electron-withdrawing strengths. The optical properties of these random terpolymers can be easily controlled by tuning the ratio between DPP and TPD. The best PCE of 6.33% was obtained from PBDTT-DPP75-TPD25 with PC71BM due to the improved light absorption and thus a JSC higher than 16 mA/cm2. Interestingly, the trend observed in the PCE values differed from that of optical behavior of the PBDTT-DPP-TPD in terms of the DPP to TPD ratio, showing from 2 to 6%. To understand the non-linear compositional dependence of the performance, density functional theory, atomic force microscopy, and grazing incidence X-ray scattering were measured. |
