Novel conjugated polymers employing the binding of polyfluorene derivatives and C-60

Abstract

New polyfluorene(PF)-based conjugated polymers, PCIBEHF, PCIBEHF-co-PDEHF. PN3BEHF, PN3BEHF-co-PDEHF, PEHPBF, PC60BEHF, PC60BEHF-co-PDEHF. and PEHPBF(+)PCBA(-) containing chloro, azido, piperidine, and fullerene (C-60) groups as pendants, were synthesized. In the case of PC60BEHF and PC60BEHF-co-PDEHF, the C-60 moiety was introduced by using covalent bond formation between the azido group and C-60. 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 PCIBEHF, PCIBEHF-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 C-60, 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 C-60. 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. (C) 2009 Elsevier B.V. All rights reserved.