Synthesis and optoelectronic properties of hexachloro- and hexaiodosubnaphthalocyanines as organic electronic materials

Chloroboron(III) hexachloro- and hexaiodosubnaphthalocyanines were prepared, and their solubility, electronic absorption spectroscopy, fluorescence emission spectroscopy and HOMO/LUMO energy levels were evaluated. These subnaphthalocyanines showed lower HOMO/LUMO energies than the parent subnaphthalocyanine by 0.13–0.39 eV. The optical band gap decreased in the order: hexafluoro->hexachloro->unsubstituted>hexaiodo-subnaphthalocyanine. Fluorescence quantum yield of hexaiodosubnaphthalocyanine was 0.05, significantly lower than those of the parent, hexafluoro- and hexachloro-subnaphthalocyanines whose quantum yields ranged from 0.2 to 0.22, indicating that the heavy atom effects of iodine work effectively.