Abstract: The absorption, photoluminescence and photovoltaic characteristics of porphyrin/TiO₂ system were studied with absorption spectra, photoluminescence spectra and transient photovoltage technology, respectively, and the interaction of interface between porphyrin and TiO₂ was also studied. The results obtained indicate that the interaction was different before and after Ho atom joined in porphyrin ring, the size of TiO₂ also affected the interaction. When porphyrin was affected by TiO₂ with 10 nm in diameter, its energy level was degenerated and band edge of porphyrin was red shifted, while it was affected by TiO₂ with 56 nm and its energy level had little change. It indicates that the delocalizing interaction existed between the big pi bond of porphyrin and surface of TiO₂ with 10 nm in diameter. The delocalizing interaction was also demonstrated via fluorescence spectra and transient photovoltage curves. Results are significant for the effective photo-electric conversion and study on the transfer of photogenerated carriers.

Key words: Interface, Interaction, Degeneracy of energy level, Charge transfer, Surface bonding