External electric field effects on absorption and fluorescence spectra of indocarbocyanine in Langmuir-Blodgett films

The change in electric dipole moment and molecular polarizability of indocarbocyanine (ICC) in Langmuir-Blodgett films upon excitation into S1 is estimated to be 5.3 × 10−32C m(0.016 D) and 3.5 × 10 −40J−1C2m2 (3.1 in units of 4πϵ0Å3), respectively, based on the electroabsorption spectra. A directional nonradiative process in S1 of ICC is also shown to be affected by an external electric field, based on the electrofluorescence spectra combined with the electroabsorption spectra.