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

Abstract

The change in electric dipole moment and molecular polarizability of indocarbocyanine (ICC) in Langmuir-Blodgett films upon excitation into S 1 is estimated to be 5.3 × 10 −32C m(0.016 D) and 3.5 × 10 −40 J −1 C 2 m 2 (3.1 in units of 4πϵ 0 A ̊ 3 ), respectively, based on the electroabsorption spectra. A directional nonradiative process in S 1 of ICC is also shown to be affected by an external electric field, based on the electrofluorescence spectra combined with the electroabsorption spectra.