| 초록 |
We introduced a thienothiophene group to increase the conjugation length. Hence, we synthesized two polymers, so-called PBDT-tTzTz and PBDT-ttTzTz. Two polymers were synthesized by Stille-coupling polymerization using anhydrous toluene and N,N'-dimethylformamide. The thermal decomposition temperatures of PBDT-tTzTz, PBDT-ttTzTz were 324, 325oC, respectively. PBDT-ttTzTz red-shifted as compared to PBDT-tTzTz because the longer conjugation length of PBDT-ttTzTz contributed to stronger intermolecular π-π stacking. To investigate photovoltaic performances, we fabricated a conventional arrangement with [ITO/PEDOT:PSS/polymer : PC71BM (3 vol% DIO)/LiF/Al], and that were measured using AM 1.5G solar simulator(100W/cm2). The maximum PCEs were 3.21% for PBDT-tTzTz and 3.88% for PBDT-ttTzTz, respectively. Also, JSC values were 7.35mA/cm2 for PBDT -tTzTz and 8.69mA/cm2 for PBDT-ttTzTz. Through this, we found that the increased JSC values led to the high photovoltaic performances. |
