Electric Field Effects on Excitation Dynamics in Electron Donor and Acceptor Pairs of Porphyrin and Fullerene

摘要

Electroabsorption and electrofluorescence spectra have been measured using electric field modulation spectroscopy for a mixture of tetraphenylporphyrin (TPP) and fullerene (C_(60)) in a PMMA film. Fluorescence of TPP is enhanced and de-enhanced by an electric field in zinc and free-base compounds, respectively, indicating that the electron transfer from the excited state of TPP to C_(60) is decelerated in zinc compound and accelerated in free-base compound by an electric field. TPP was also found to form complex upon mixing with C_(60) which exhibits a broad emission in the wavelength region longer than that of TPP emission. The electroabsorption spectra show that a charge separation occurs upon photoexcitation to the absorption band located near the Soret band. The complex emission is significantly quenched by an external electric field in both zinc and free base compounds, suggesting that the nonradiative decay of the excited complex is accelerated by an electric field.