1P-72: Two novel conjugated polymers through indacenodithiophne and Di-fluorinated quinoxaline for OPVs

The new D-A alternating copolymers (PIDT-DFQx, PIDT-DTDFQx), which have low band gap were synthesized by a Stille coupling polymerization using Pd catalyst. indacenodithiophene (IDT) having a alkyl phenyl group was used as an electron-rich unit. On the other hand, Di-fluorinated quinoxaline (DFQx) was used as an electron-deficient unit. In an attempt to look into impact of thiophene bridge, either DFQx or that of having a thiophene group on both side was designed and synthesized. Two polymers showed strong absorption peaks in the range of 558- 576 nm in solution state. PIDT-DTDFQx displayed the more broad absorption spectra than PIDT-DFQx. Therefore, it is important for the polymer to have a thiophene as a molecular spacer for facilitating the electronic coupling. Consequently, 0.93%, 2.87% of power conversion efficiency (PCE) were shown in these polymers, respectively.