Novel conjugated polymers employing the binding of polyfluorene derivatives and C60

New polyfluorene (PF)-based conjugated polymers, PClBEHF, PClBEHF-co-PDEHF, PN3BEHF, PN3BEHF-co-PDEHF, PEHPBF, PC60BEHF, PC60BEHF-co-PDEHF, and PEHPBF+PCBA− containing chloro, azido, piperidine, and fullerene (C60) groups as pendants, were synthesized. In the case of PC60BEHF and PC60BEHF-co-PDEHF, the C60 moiety was introduced by using covalent bond formation between the azido group and C60. PEHPBF+PCBA− was synthesized by using ionic bond formation between the piperidinium cation of PEHPBF and carboxylate anion of PCBA. The PL and EL spectra of PClBEHF, PClBEHF-co-PDEHF, PN3BEHF, PN3BEHF-co-PDEHF, and PEHPBF exhibited red-shifted and broad peaks caused by the aggregation which was induced by the increasing interchain interaction due to the polar pendants. After binding with C60, covalently and ionically, the photovoltaic properties of PC60BEHF, PC60BEHF-co-PDEHF, and PEHPBF+PCBA− were studied. PL was quenched completely, which indicates photo-induced charge transfer from PF to pendant C60. Even though photovoltaic effects did not occur in short circuit condition, blending with MEH-PPV as the ratio of 1:1 generated the photovoltaic effects.