Poly(quinoxaline vinylene) with conjugated phenylenevinylene side chain: A potential polymer acceptor with broad absorption band

Alkoxyl phenylenevinylene substituted poly(quinoxaline vinylene) (PV-PQV) was designed and synthesized. The polymer film showed a broad absorption band from 300 to 704 nm with a lower bandgap of 1.76 eV. The onset oxidation potential [E_ox) and onset reduction potential (E_red) of PV-PQV were 0.51 and -0.89 V (versus Ag/Ag⁺), corresponding to a HOMO level of -5.22 eV and a LUMO level of -3.82 eV, respectively. The results indicate that PV-PQV possesses a higher electron affinity similar to other polyquinoxaline derivatives. The strong photoluminescence of MEH-PPV was entirely quenched by PV-PQV in a polymer blend solution of MEH-PPV and PV-PQV, which suggests that electron transfer from the excitons of MEH-PPV to PV-PQV occurs after MEH-PPV is photoexcited. Owing to the broad absorption band in the visible region and the high electron affinity, PV-PQV could be a promising polymer photovoltaic acceptor material.