Naphtho[4,3,2,1-lmn][2,9]phenanthrolines: Synthesis, сharacterization, optical properties and light-induced electron transfer in composites with the semiconducting polymer MEH-PPV

Novel naphtho[4,3,2,1-lmn][2,9]phenanthrolines were synthesized via reaction between 1,5-diethynyl-9,10-anthraquinones and urea in DMF. Their HOMO and LUMO levels determined from optical spectroscopy and cyclic voltammetry are in good agreement with those determined from quantum chemical calculation. Light-induced electron transfer from the semiconducting polymer MEH-PPV to the synthesized molecules was detected by EPR-spectroscopy, showing their possible applicability as electron acceptors in bulk heterojunction organic solar cells. The synthesized naphtho[4,3,2,1-lmn][2,9]phenanthrolines can be used as building blocks for larger molecules with an extended π-conjugated system, which can be used as acceptors in organic photovoltaics.