Photoinduced electron transfer between dye IR-140 and TiO2colloids by femtosecond pump supercontinuum probing

Abstract

We employ the femtosecond pump supercontinuum-probing technique to investigate the photoinduced electron transfer (ET) dynamics in dye IR-140 sensitized TiO2 nanoparticles (average diameter ~ 7 nm) in ethanol. After 807 nm excitation, transient absorption spectra and kinetics are recorded in the spectral region from 400 to 1000 nm, the fluorescence quenching correlated to the electron injection process is observed and the electron injection time from the excited singlet state of dye IR-140 into the conductor band of TiO2 nanoparticles is measured to be ~ 200 fs. The strong quenching of the emission yield and the shortening of the fluorescence lifetime were verified in the dye associated with the TiO2 surface in ethanol.