Excitation energy transfer in porous silicon/laser dye composites

Excited state relaxation and energy transfer in porous silicon (PS)/laser dye [oxazine 1 (Ox1), rhodamine 6G (Rh6G)] composites have been studied by means of steady-state and time-resolved fluorescence. Fluorescence decay kinetics reveals the nonradiative energy transfer from PS to the dye. Increased decay rate of the dye luminescence in the composite indicates that opposite energy transfer is also likely. Analysis of the time-resolved fluorescence of the PS/R6G composite also shows that there is no energy transfer from silicon oxide responsible for the blue fluorescence band to silicon nanocrystalites, and that interaction between Si nanocrystals responsible for the red PS fluorescence is absent or weak.