Supramolecular photovoltaic cells utilizing inclusion complexes composed of Li ⁺@ C ₆₀ and cyclic porphyrin dimer

We have newly constructed supramolecular photovoltaic cells using inclusion complexes of lithium-ion-encapsulated [60]fullerene (Li⁺@C₆₀) and cyclic porphyrin dimers (M-CPDPy, M = H₄ and Ni₂). First, supramolecular inclusion complexes of LiC₆₀ and M-CPDPy were prepared in MeCN/PhCN (3/1, v/v) by rapid injection method. The molecular aggregates with spherical nanoparticles demonstrated a broad absorption property in the visible region. The macroscopic structures were also estimated to be ca. 200 nm in diameter by transmission electron microscope (TEM) and dynamic light scattering (DLS) measurements. The photoelectrochemical solar cells composed of these assemblies on nanostructured SnO₂ electrode were fabricated by electrophoretic deposition method. The photoelectrochemical behavior of the nanostructured SnO2 film of supramolecular nanoassemblies of Li⁺C₆₀ and M-CPDPy is significantly higher than those of the single component films (Li⁺C60 or M-CPDPy) and supramolecular inclusion complexes of pristine C₆₀ and M-CPDPy.