A conformationally stressed novel ball-type perylenediimide appended zinc(ii)phthalocyanine hybrid: spectroelectrochemical, electrocolorimetric and photovoltaic properties†
A supramolecule, 6, based on an electron-donor zinc phthalocyanine (ZnPc) and an electron-acceptor perylene diimide (PDI) has been synthesized and characterized by elemental analysis, UV/Vis, IR, 1H NMR and solid state 13C CPMAS NMR and also MALDI-TOF and ICP mass spectrometry. The PDI appended ZnPc core brings about a geometrical constraint in the molecule with intriguing spectroscopic, electrochemical and photovoltaic properties. The first reduction process of 6 occurs on the PDI core while the first oxidation takes place on the Pc ring. These processes reflect a considerably small HOMO–LUMO gap of 1.50 eV, which has vital importance for optoelectronic applications. In addition, the PDI-based first and second reduction processes of 6 are accompanied by an electrochromic behaviour with colour changes from dark purple to blue and blue to turquoise, respectively. A photovoltaic cell involving 6 as the donor and [6,6]-phenyl C61 butyric acid methyl ester as the acceptor has been fabricated. The measurements of the effect of annealing temperature on its performance indicated that the annealing process gives rise to a significant increase in the open circuit voltage, the fill factor and the photoconversion efficiency.